4326 4330.output

* GB784733 (A)
Description: GB784733 (A) ? 1957-10-16
Improvements relating to electrical apparatus for measuring torsional forces
or oscillation in rotating bodies
Description of GB784733 (A)
COMPLETE SPECIFICATION
Improvements relating to electrical Apparatus for Measuring
Torsional Forces or Oscillation in Rotating Bodies
We, DAIMLER-BENZ ARTIENGESELLSCHAFTN
of Stuttgart-Unterturkheim, Germany, a Com-
pany organised under the Laws of Germany
do hereby declare the invention, for which we
pray that a patent may be granted to us, and the method by which it is
to be performed, to
be particularly described in and by the fol
lowing statement:
This invention concerns improvements
relating to electrical instruments for measur
ing torsional forces or oscillations in rotating
bodies, for example shafts or other parts of
machines, of the kind utilising carrier-fre
quency modulation. In such apparatus, for instance as described in the
Specifications of
our Patents Nos. 762,668 and 773,582 the forces or oscillations are
measured by means
of electrical variations produced by the rela
tive movement of measuring elements such
as coils and magnetic cores or parts of a con
denser which are secured to different parts of
the rotating body or to a part of the said body
and to an inertia mass respectively. The elec
trical variation is then utilised to cause modu
lation of a carrier-frequency current in a
bridge whose output is amplified and passed to a demodulator connected

to an indicating
or recording device. It is accordingly neces
sary to establish electrical connection between
parts of the circuit which rotate with the rotate
ing body on the one hand and parts of the
circuit which do not rotate on the other hand.
Heretofore it has been proposed to estab
lish this connection by means of slip rings. Such slip rings, however,
intro
duce relatively high contact resistances
whose influence is the more detrimental
to the measurement the smaller the aforesaid electrical variations.
Furthermore
changes in the resistance at the slip rings due
to wear of the carbon brushes or to jumping
of the said brushes at high speeds of revolu
tion have a particularly disadvantageous effect
when carrier-frequency modulation is utilised
as aforesaid. High contact pressure for the
brushes will remedy the disadvantage to some extent, but aggravates
the brush wear. The detrimental effect of the slip rings can be
reduced by arranging for the bridge, not merely the measuring
elements, to rotate with the rotating body. However, the presence of
the slip rings is still disadvantageous and their operation imperfect,
especially at high revolution. speeds. The present invention seeks to
obivate the above-described deficiencies by eliminating the slip
rings.
According to the invention, in an electrical instrument for measuring
torsional forces or oscillations in a rotating body, measurement is
effected by means of electrical variations produced in elements
rotating with the said body, which variations are used to modulate a
carrier-frequency current in a bridge connected through an amplifier
and demodulatoi: to an indicating or recording device, the bridge
being also arranged to rotate with the said body and being coupled
inductively, without the use of slip rings, both to a generator
supplying the carrier frequency current and to the amplifier.
Thus the coupling may be effected by a pair of coils of which one is
connected electrically to the generator and the other to input
terminals of the bridge and a pair of coils of which one is connected
electrically to the amplifier and the other to output terminals of the
bridge, the second-named coils of each pair being connected to the
rotating body so as to rotate therewith while the first-named coils
are stationary, and the pairs of coils being disposed side by side.
Preferably, the coils connected to the generator and to the amplifier

are disposed concentrically around the outsides of the other coils of
the respective pairs.
It will be appreciated that although there is relative rotation
between the coils of the respective pairs, this does not affect the
paths for the magnetic fluxes linked with them.
Each of the coils may be disposed in an annular yoke of U-shaped cross
section and preferably made of laminated soft iron, the open sides of
the U-sections of the yokes of inner and outer coils of respective
pairs facing each other.
Advantageously, the limbs of the U-sections of the yokes facing each
other are of different widths, so that slight relative axial
displacement can take place between the inner coils and the outer
coils without the narrower limbs passing outside the limits of the
widths of the wider limbs. Consequently such axial displacement, due
say to play in bearings between the rotating and stationary parts of
the instrument, can take place without materially affecting the paths,
between the said limbs, fot the magnetic fluxes. The radial gap
between the inner and outer coils should be such that unavoidable
relative movement in the radial direction, due to say out-of-true
running in the said bearings does not materially affect the coupling
or the accuracy of measurement.
The pairs of coils are preferably screened against each other in order
to avoid undesirable capacitative interaction which would affect the
bridge. Furthermore, the coils are preferably wound symmetrically and
so that the ends have the same capacity relationship to earth.
One embodiment of the invention is shown, by way of example, in the
accompanying drawing, in which:
Figure 1. is an electrical circuit diagram of an instrument working
with carrier-frequency modulation, and
Figure 2 is a longitudinal section through a coupling arrangement used
in the instrument according to the diagram of Figure 1.
In Figure 1, a conevntional bridge B corn- prises two measuring coils
1, 2 and two resistances 3, 4 which are adjustable for initially
balancing the bridge. The bridge B is supplied with carrier-frequency
current by an alternating current generator W. The output of the
bridge is connected through an amplifier V to a phase-sensitive
demodulator G and a filter network S which is connected in turn to an
indicating or recording device A in the form of a moving coil
instrument or oscillograph.
The Bridge B is not directly connected to the generator W or to the
amplifier V by means of slip rings, but is inductively coupled thereto
by two pairs of coils Si, SO and S,, S t.
As shown in Figure 2, the coils Sl and S, are disposed, at a short
distance apart, side by side on a shaft member 5 which is secured, for

example by means of a threaded sleeve 6, to one end of a shaft to be
examined, that is the rotating body upon which measurements are to be
performed. It would be so secured in the same fashion as and, indeed,
in place of slip-ring assemblies such as are described and illustrated
in the aforesaid specifications.
As in the said specifications, moreover, the measuring coils 1, 2 and
coacting magnetic cores are mounted on respective parts of the said
shaft or on the shaft and an inertia mass, depending upon the
measurement to be effected.
The coils Sl and S, are disposed in annular yokes, 7, 7a respectively,
having a
U-shaped cross-section which is open outwaidly. These yokes may be of
laminated construction or may be slit radially to prevent eddy
currents. A magnetic screen 9 is disposed around each yoke, from which
it is separated by inserts 10 of electrical insulating material. A
spacing ring 11 is disposed between the yokes The entire coil assembly
Si, S,. 7, 7a is electrically insulated from the shaft member 5 by
inserts 12. A bellshaped housing 14 carrying the coils S2 and
S4 is mounted on the shaft member 5 by means of anti-friction bearings
13. The coils So, S, are also disposed in U-section laminated or slit
yokes 15, 16, which are open inwardly to face the yokes 7, 7a and
which are screened and insulated in the same way as the yokes 7, 7e
and spaced apart by a ring 18.
The coil assembly S 52, 84, 15, 16 is secured in the housing 14 by
screws 19 by which it is clamped between an end ring 20 and a ring 21
forming part of the housing. The coils S, and S1 are located
concentrically outside the coils Si and S, and in axial register
therewith. The air gap L between the coils and S2 and between the
coils S, and S4 is made as small as possible consistently with the
requirement that it should be sufficiently large for unavoidable
relative movement of the coils in the radial direction, for example
due to out-of-true running in the bearings, to have practically no
disturbing influence on the measurement. Moreover, the limbs of the
U-sections of the yokes 15 and 16 enclosing the coils So and S1, for
example, are made wider than those of the yokes 7 and 7a enclosing the
coils Si and S,. They are made at least so wide that the path for the
flux between the limbs of the yokes (for example between the yokes 7
and 15) is always fully maintained by the narrower lin;bs of the yokes
7, 7a remaining wititin the limits of the wider limbs of the yokes 15,
16, even if there is slight relative axial movement between the coils
S1 and S, and the coils S2 and S1. The leads for the coils S2 and Sl
are brought in through a hole 17 which is provided in the rounded end
of the housing 14 and which is provided with a liquid-tight and
gas-tight seal. The leads for the coils Si and So are brought out

through the shaft member 5 at the end provided with the sleeve 6 and
are connected directly to the bridge B the whole of which is mounted
on the shaft to be examined so as to rotate therewith. The aforesaid
Specify cations illustrate how the measuring coils mag be mounted so
as to rotate with the rotating body. In the present case, not merely
the coils 1, 2, but the whole bridge, is similarly mounted. The coils
Sl and S, and the coils SB and St are wound symmetrically, for example
from the inner ends adjacent the rings 11, 18 towards the outer ends
(to the right and the left in Figure 2). The spacing rings 11 and/or
18 may be proivded with radial bores for balancing purposes.
If it is not possible to secure the coupling arrangement on the end of
a shali: to be examined, the inner coils S1 and S, may be mounted on a
bush to be pushed directly on to the said shaft.
The operation of the circuit shown in
Figure 1, apart from the coupling at the coils
S,, S, and S3, S4, is per Se known and is described in the aforesaid
Specifications: On disturbance of the balance of the bridge B by
variation of the inductanoe of the coils 1, 2 due to relative movement
between them and their cores, an alternating voltage modulated in
dependence upon the said relative movement will appear across the
output terminals of the bridge. This is fed by way of the coils S3, S4
to the amplifier V and the demodulator G. The demodulator output,
which is substantially proportional to the aforesaid relative
movement, is smoothed by the filter network S and supplied to the
indicating or recording device A.
What we claim is: -
1. An electrical instrument for measuring torsional forces or
oscillations in a rotating body, in which measurement is effected by
means of electrical variations produced in elements rotating with the
said body, which variations are used to modulate a carrier-frequency
current in a bridge connected through an amplifier and demodulator to
an indicating or recording device, the bridge being also arranged to
rotate with the said body and being coupled inductively, without the
use of slip rings, both to a generator supplying the carrier frequency
current and to the amplifier.
2. An instrument as claimed in Claim 1, wherein the coupling is
effected by a pair of coils of which one is connected electrically to
the generator and the other to input terminals of the bridge and a
pair of coils of which one is connected electrically to the amplifier
and the other to output terminals of the bridge, the second-named
coils of each pair being connected to the rotating body so as to
rotate therewith while the first-named coils are stationary, and the
pairs of coils being disposed side by side.
3. An instrument as claimed in Claim 2, vvherein the coils connected

to the generator and to the amplifier are disposed concentrically
around the outsides of the other coils of the respective pairs.
4. An instrument as claimed in Claim 2 or 3, wherein each of the coils
is disposed in an annular yoke of U-shaped cross-section, the open
sides of the U-sections of the yokes of inner and outer coils of
respective pairs facing each other.
5. An instrument as claimed in Claim 4, wherein the limbs of the
U-sections of the yokes facing each other are of different widths, so
that slight relative axial displacement can take place between the
inner coils and the outer coils without the narrower limbs passing
outside the limits of the widths of the wider limbs.
6. An instrument as claimed in any one of
Claims 2 to 5, wherein the coils are wound symmetrically.
Claims 2 to 6, wherein the coils connected to the bridge are mounted
on a shaft member provided with means for securing it on the end of a
shaft to be examined.
Claims 2 to 6, wherein the coils connected to the bridge are mounted
on a bush to be pushed on a shaft to be examined.
Claims 2-8, wherein the pairs of coils are maintained apart axially by
spacing rings.
10. An instrument as claimed in Claim 9, wherein the spacing rings are
formed with bores for balancing purposes.
11. An instrument as claimed in any one of Claims 7 to 10, wherein the
coils connected to the generator and amplifier are mounted in a
housing in relation to which the shaft member or bush is rotatable.
12. An instrument as claimed in any one of Claims 4 to 11, wherein the
yoke of each coil is screened from the yoke of the adjacent coil of
the other pair.
13. An instrument as claimed in Claim 12, wherein electrical
insulation is provided between the yokes and their screening means.
14. An instrument as claimed in Claim 13, wherein the yokes with their
screening means are electrically insulated from the parts on which
they are mounted.
Claims 2 to 14, wherein the coils connected to the generator and the
amplifier are carried in a bell-shaped housing into which the
electrical connections for the said coils are brought at the rounded
end through a hole provided with a liquid-tight and gas-tight seal. -
16. An instrument as claimed in Claim 15, wherein the housing is
mounted by means of anti-friction bearings on a member which is
connectable to the rotatable body and which carries the coils

connected to the bridge.
17. The electrical instrument for measuring torsional forces or
oscillations in a rotating body substantially as hereinbefore
described with reference to the accompanying drawing.
* GB784734 (A)
Description: GB784734 (A) ? 1957-10-16
Device for producing a gas at low pressure from a supply of compressed or
liquefied gas
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amongst the following family members:
BE544094 (A) CH339236 (A) DE1001298 (B) FR1118541 (A)
BE544094 (A) CH339236 (A) DE1001298 (B) FR1118541 (A) less
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The EPO does not accept any responsibility for the accuracy of data
and information originating from other authorities than the EPO; in
particular, the EPO does not guarantee that they are complete,
up-to-date or fit for specific purposes.
PAT-ENT
89 ? 7 E 1 ECATEON Daeo ppiainan iig o pee 7 84,7 34
B O< Date of Application and filing Complete Specification Dec30,1955.
No 37351/55.
Application made in France on Jan 4, 1955.
Complete Specification Published Oct 16, 1957.
Index at Acceptance:-Class 8 ( 2), F 2, CA (A 2: Bl BSX).
International Classification: -F 253.
Device for Produchng a Gas at Lowr Fressure from a supply of

Compressed or Liquefied Gas We, LA CARBONIQUE FRANCAISE, a French Body
Corporate, residing at 171, Avenue Heari Barbusse, Bobigny, Seine,
France, do hereby declare the invention for which we pray that a
patent may be granted to us, and the method by which it is to be
performed, to be particularly described in and by the following
statement: The present invention relates to a device adapted to
produce a gas at low pressure from a supply of a compressed or
liquefied gas, without freezing its water vapour content.
Usually, when a gas is subjected to isenthalpic expansion m a
conventional pressure17 reducer, freezing of its water vapour content
takes place owing to temperature fall in the pressure-reducer
Moreover, when the gas is obtained from a liquid by vaporisation, said
freezing takes place most generally within the container of the
liquefied gas owing to cold being generated by the vaporisation of the
liquid Such a freezing may also cause detrimental ice formation on the
apparatus parts.
With a view to remove such drawbacks, it is an object of the present
invention to provide an apparatus for producing a gas at low pressure
from a supply of a compressed or liquefied gas, wherein the gas is
drawn from its container and means are provided for heating the gas,
while being vaporized if said gas is a liquefied gas, by conduction
from a heated liquid up to such a temperature that after expansion the
temperature of the expanded gas never falls down below 00 C thereby
avoiding the freezing of the water vapour content of the compressed or
liquefied gas when said gas is expanded.
It is another object of the present invention to provide an apparatus
of the character described comprising a closed chamber containing a
liquid maintained at a predetermined temperature by any suitable
heating means and a coiled pipe connected between the compressed or
liquefied gas container and a pressurereducer, said coiled pipe being
wholly lPice 3 s 6 d l immersed within the liquid in said chamber, the
predetermined temperature being such that the temperature of the
expanded gas flowing from the pressure-reducer is at least equal to 00
C The coiled pipe is made of a metal, such as steel or copper, having
a high thermal conductivity and a breaking strength sufficient for
resisting the high pressures experienced in operation.
Any sudtable liquid may be used for heating the coiled pipe However,
it is convenient to use a liquid having both a low volatility and a
fairly high coefficient of thermal conduction or convection Such a
liquid may be for example oil, mercury, or water, the latter being
surmounted by oil for avoiding vaporisation losses.
According to a preferred embodiment, the liquid in the closed chamber
is heated by means of a resistor operating during periods of time the
duration of which is controlled according to the rate of flow of the

fluid through the coiled pipe.
Such a control is preferably made through a resistor-controlling
thermostat actuated by pulses applied from a temperature-sensitive
bulb located in the gas circuit between the coiled pipe and the
pressure-reducer, such as a bulb in a sheath filled with oil or any
other thermo-conductive liquid.
Other features of the invention will appear in the following
description of an embodiment thereof, with reference to the
accompanying drawings, in which:Figure 1 is a diagrammatical view of
an apparatus for expanding liquefied carbon dioxide, according to the
invention; Figure 2 shows an alternative heating device for the
apparatus illustrated in Figure 1; Figure 3 shows a modified inlet of
the coiled pipe as may be used for gases with a triple point, such as
carbon dioxide, in order to avoid failure in operation.
The invention will be described hereafter as applied to the expansion
of liquefied carbon dioxide, but it should be understood that the -v
784,734 illustrated apparatus parts may be used for any other
liquefied or compressed gas.
Referring to Figure 1, a plunger pipe 1 is disposed in a liquefied
carbon dioxide storage bottle 2 and extends to the bottom of said
bottle Said plunger pipe I is connected to the bottle outlet valve 3
provided with a safety capsule 4 of a known type, such as a bursting
capsule The valve 3 is connected through a pipe 5 to a connecting
member 6 on which is fitted another bqrsting capsule 7 Said member 6
is connected through a pipe 8 to a coiled pipe 9 made of copper or
steel itself connected through a pipe 10 to a closed chamber 11.
Said chamber 11 is also connected through a pipe 12 to a
pressure-reducer 13 from -which the expanded gas is delivered through
the outlet pipe 14 Pressure gauges 15, 16 are connected to the pipes
12, 14 respectively for indicating the gas pressure before and after
expansion.
The coiled pipe 9 is arranged within a closed chamber 17 filled with a
liquid having a low volatility and a high coefficient of thermal
conduction or convection, such as oil.
A level meter 18 extending into the chamber 17 through the filling
port of said chamber is provided for measuring the liquid level A
resistor 19 of cylindrical shape also extends into the chamber 17
through the top thereof and is arranged coaxially with the coiled pipe
9 The resistor 19 is energized under the control of a thermostat 20
actuated by pulses supplied from a temperature-sensitive bulb
accommodated within a sheath 22 filled with oil or any other
thermo-conductive liquid and welded to the wall of the chamber 11.
The above described device operates as follows:When the valve 3 is
opened, the compressed gas flows from the bottle 2 through the coiled

pipe 9 to be heated therein by the thermo-conductive liquid contained
in the chamber 17 wherein said liquid is subjected to the action of
the heating resistor 19 The gas flows from the coiled pipe 9 through
the pipe 10 into the chamber 11 and thence through the pressurereducer
from which it is delivered through the pipe 14.
If the rate of flow through the coiled pipe increases, the temperature
will tend to fall within the chamber 11, and the bulb 21 will respond
to such temperature fall by supplying a pulse to the thermostat 20
which will switch on the electric current to feed the resistor 19 so
as to restore the predetermined temperature The temperature to be
maintained within the chamber 11 depends on the pressure prevailing in
the bottle 2 and may be determined by means of the isenthalpic
expansion curves of the entropy diagram of the gas in such a manner
that the final temperature, after expansion, will be higher than O C
By way of example, for carbon dioxide, the temperature in chamber 11
should be maintained at 550 C.
when the gas pressure in the bottle 2 is 710 lbs /sq in, and at 755 C
when said pressure is 1140 lbs /sq in.
The bursting capsule 7 serves to avoid a rupture of the coiled pipe 9
which may be 70 caused by the surge of pressure occurring when,
inadvertently, the bottle outlet valve 3 and the pressure-reducer 13
are closed simultaneously.
Figure 2 shows an alternative embodiment 75 of the heating chamber
which permits to take advantage of the convection effect in the
heating liquid and, at the same time, to use a liquid such as water
which satisfactorily provides the characteristics required for the
heat 80 ing liquid However, in this case, the mass of water 23 is slu
mounted Hithin the chamber 17 a by a layer of oil 24 for the purpose
of preventing water vaporisation The cylindrical resistor 19 a, in
that case, extends 85 through the bottom of the chamber 17 a.
In the case of substances having a triple point in their phase
equilibrium diagram, such as carbon dioxide, an inadvertent opening of
the valve 3 before the heating device has been 90 made operative may
cause a formation of carbon dioxide snow within the pressurereducer
13, thus preventing the outlet of expanded gas through the pipe 14 In
such an occurrence, there is no remedy but to remove, 95 clean and
mount back the pressure-reducer.
For avoiding such a drawback, the pipe 8 a illustrated in Figure 3
terminates short of the coiled pipe 9 and opens into a chamber 25.
equal to that of the passage through the outlet 100 The inner
cross-section of the pipe 8 a is valve 3 If said valve and the
pressure-reducer 13 are opened before the heating device is operative,
the compressed gas flowing from the pipe 8 a is expanded in the
chamber 25 and a 105 mass of carbon dioxide snow builds up in said

chamber and stops up the inlet into the coiled pipe 9 The gas flow is
thus checked However, when subsequently the heating device is put in
operation, said carbon dioxide snow 110 mass is immediately vaporised
and the flow is thus restored without any part having to be
disconnected from the apparatus.
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* GB784735 (A)
Description: GB784735 (A) ? 1957-10-16
Improvements in pressure seal structures for a movable rod-like element
PATENT SPECIFICATION
784,735 Date of Application and filing Complete Specification: Dec 30,
1955.
No 37451 /55.
Application made in United States of America on Jan 14, 1955.
r,,, 'Complete Specification Published: Oct 16, 1957.
Index at Acceptance:-Class 122 ( 5), B 13 (B 3 A 3:133 A 8: B 3 E 1:
CX: D: G).
International Classification:-FO 6 J.
Improvements in pressure seal structures for a movable rod-like
element We, GENERAL ELECTRIC COMPANY, a Corporation of the State of
New York, United States of America, having its office at Schenectady
5, State of New York, United States of America, do hereby declare the
invention, for which we pray that a patent may be granted to us, and
the method by which it is to be performed, to be particularly
described in and by the following statement:-

This invention relates to a pressure seal structure for preventing
appreciable leakage around a movable rod-like element extending
through a wall of a chamber containing gas under either low or high
pressure.
In the chemical, metallurgical and related arts an increasing use is
being made of reaction and treatment apparatus involving vacuum or
very high pressure chambers.
One of the difficulties encountered in the use of such apparatus is
the provision of adequate seals about movable elements which extend
-through the chamber walls These elements may have a variety of
functions but usually they must move freely with respect to the
opening in the chamber wall For example, such an element may have a
rod or shaft-like configuration and be used to manipulate apparatus or
materials within the chamber, may serve as a drive shaft for mechanism
within the chamber, may serve to conduct material to or from the
chamber, or perform any other function which may require relative
motion between the element and the container wall structure.
A particularly difficult sealing problem has been encountered in the
metal casting art in the adaptation of continuous casting apparatus to
the vacuum melting furnace technique Conventionally, such continuous
casting apparatus usually consists of a melting furnace to which
material to be melted is charged by any suitable means The molten
material is continuously tapped from the crucible of the furnace into
a tubular lPrice 3 s 6 d l mould, the molten material solidifying in
the upper portion of the mould and the solid ingot or bar thus formed
being continuously extracted through the open bottom of the mould The
specific details of such continuous casting apparatus are well known
and form no part of the present invention.
The extracted bar or ingot so produced is usually quite hot and
frequently does not have a smooth surface Where the material being
continuously cast in this manner does not require melting in a vacuum
such as, for example, brass or other similar alloys, the various
operations may be carried out in the atmosphere without difficulty
However, certain molten metals and alloys react quite readily with
gases of the atmosphere and are usually commercially produced in
vacuum furnaces of the batch type in which it is sometimes necessary
to maintain pressures of the order of 10-2 to 10-5 mm of mercury In
order to operate such a continuous casting apparatus in an evacuated
enclosure, provision must be made for the continuous extraction of the
hot rod-like bar or ingot from the evacuated enclosure without loss of
vacuum Because the temperature of newly cast ingots of metals such as
titanium, for example, may be of the order of 10 00 C or higher, a
deformable seal of the gland and stuffing box type is unsuitable due
to rapid destruction of the packing material Furthermore, a seal which

depends primarily upon an intimate physical contact between the
sealing element and the surface of the ingot to perform its sealing
function is unsatisfactory primarily due to the irregularity of the
surface of the ingot.
In addition to providing an adequate barrier to gases of the
atmosphere, such a seal must not be excessively large.
The invention provides a tubular seal structure particularly useful
with such a vacuum chamber and rod-like element or bar, which includes
supplementary annular Price 25 P 784,735 pumping chambers or bustles
interposed between the rod-like bar element and the opening in the
wall structure of the vacuum chamber by means of which gases leaking
past the periphery of the rod-like element may be pumped away The
pumping chambers or bustles are separated from each other by means of
metallic flexible conical gas traps which permit the maintenance of
sizeable pressure differentials between adjoining chambers In this
manner, a gross pressure differential may be maintained across a
series of bustle chambers which is the sum of the individual pressure
gradients across each chamber.
While the seal of the invention is particularly suited for overcoming
the problems involved in extracting a hot bar or ingot from a vacuum
chamber, it is equally suitable for other and specifically different
uses.
For example, the improved seal is equally adaptable for inserting a
rod-like element into a vacuum chamber In this manner, material to be
melted in a vacuum enclosed continuous casting apparatus may be
continuously charged into the furnace crucible without loss of the
vacuum by passing a rod-like element of the material through an
appropriately located seal in a wall of the vacuum chamber
Additionally, in the event that a consumable electrode arc furnace is
employed in such an apparatus, the rod-like element may constitute the
consumable electrode The seal may also be employed where the relative
motion between the rod-like element and wall structure is rotary or
reciprocating The chamber may in any case contain gas at an elevated
pressure instead of being evacuated.
A tubular pressure seal structure for regulating and controlling gas
leakage around a rod-like element extending longitudinally through and
movable in an aperture in a wall adapted to separate a body of gas at
high pressure from a body of gas at a lower pressure comprises,
according to this invention a substantially tubular element adapted to
be secured to and extend from the wall and to encompass the aperture
therein, the tubular element having an internal passage therethrough
of a size and configuration similar to but larger by a small but
discrete amount than the crosssection of a rod-like element which is
to pass therethrough, a plurality of spaced pairs of resilient sheet

metal gas trap elements secured at their outer edges to the interior
of the tubular element and having centrally disposed resiliently
expansible apertures through which the rod-like element is to pass,
the portions of the trap elements defining the apertures being adapted
to maintain a substantially continuous frictional line-contact with
the periphery of the rod-like element whereby a plurality of
substantially closed annular chambers are adapted to be formed between
the interior of the tubular element and the rod-like element, and
means whereby the gas pressure in at least one of the annular chambers
may be modified 70 The invention will be better understood from the
following detailed description of the accompanying drawing in which:
Fig 1 is a fragmentary sectional view of a schematically represented
vacuum chamber, 75 rod-like element and sealing means taken along line
1-1 of Fig 2; Fig 2 is a fragmentary sectional view taken along line
2-2 in Fig 1; Fig 3 is a detail view of a conical gas 80 trap element;
and Fig 4 is a large scale fragmentary detailed view of a gas trap
element.
With particular reference to Fig 1, a portion of the wall structure of
a vacuum 85 container 1 is provided with an aperture 2.
Vacuum container 1 is provided with a vacuum source or pumping means
of any suitable construction which has not been shown A rod-like
element 3 extends 90 through aperture 2 from the interior of the
vacuum chamber and is dimensioned so that it is slightly smaller than
aperture 2 A tubular seal structure generally indicated by reference
numeral 4 comprises a tubular 95 structure 5 secured to the container
and extending outwardly from the periphery of aperture 2 A helical
passage 6 may be provided in element 5 with a confining element 7 for
a purpose to be later disclosed 100 A flange 8 is formed at the outer
end of element 5 and is provided with a continuous recess 9 encircling
the open end of tube 5.
Subjacent to flange 8 and bearing thereon is a plate element 10
containing an internal 105 passageway 11 which is located adjacent
recess 9 A sealing element or ring 12 of resilient material such as a
suitable elastomer is contained in recess 9 and compressed therein by
plate-like element 10 to form a 110 seal Plate-like element 10 is
centrally apertured at 13, the size and configuration of the aperture
being substantially identical to the internal opening of tubular
element 5 and coinciding therewith 115 A bustle chamber-forming
element 14 is provided with a substantially cylindrical aperture 15
which is somewhat larger than aperture 13 of plate 10 and is
concentric therewith The upper surface of element 14 120 is positioned
against the lower surface of element 10 and is provided with a
continuous recess 16 which is similar to recess 9 in flange 8 and is
located adjacent passage 11 in element 10 Contained and compacted 125

within recess 16 is sealing element 17 similar in all respects to ring
12 The bottom surface of element 14 contains a recess 18 and sealing
ring 19 similar in all respects to recesses 9 and 16 and rings 12 and
17 130 verse dimension, the slits may substantially 65 close.
While in Fig 1 the seal is shown with only two bustle chambers, it is
to be appreciated that as many or as few bustle chamber forming
elements and the intervening spacer 70 plates such as element 20 may
be assembled in one array as desired, the various elements of such an
array being clamped together by any suitable and preferably removable
means Such a clamping or securing means 75 has been illustrated by the
bolt and nut assemblies shown, for example at 33.
In the application of the seal of the invention to the extraction of a
continuously cast ingot or bar from a vacuum chamber 80 as disclosed
previously, rod-like element 3 represents a hot, newly cast ingot or
bar continuously moving outwardly through aperture 2 In order to
reduce the transfer of heat by conduction along tubular element 85 a
cooling media such as water is preferably circulated in helical
passage 6 Further, in order to maintain the ring seals shown at 12,
17, 19, for example, at a suitable low temperature, a cooling media
may also be 90 circulated through passages 11, 21 and 26, as excessive
heat may tend to destroy the seals The outer dimension of the newly
cast ingot 3 is somewhat larger than the aperture in trap elements 30
and causes the 95 material between the radial slits 32 in the conical
section 31 of these elements to flex slightly outwardly Under these
conditions slits 32 open slightly to form small elongated triangular
openings, as shown in Fig 4 In 100 Fig 4, the size of the triangular
openings have been exaggerated for clarity Since a relatively tight
line-contact is maintained between the inner periphery of the central
aperture of element 30 and the outer peri 105 phery of element 3, gas
flow from one side of a gas trap element 30 to the outer side is
substantially limited to that amount of gas which can pass through the
very small apertures formed by the slits 32 It should be 110 noted
that the line-contact between elements and element 3 is maintained not
only by the resilience of the sheet metal, but also by the pressure
drop across each element 30.
Therefore, with respect to any given bustle 115 chamber forming
element, for example 14, the upper and lower trap elements 30
associated therewith in co-operation with the oiiter periphery of
element 3 form a substantially enclosed annular compartment 120 which
may be connected to a vacuum source by means of a conduit such as
shown at 34.
The outer end of the conduit portion may be conveniently provided with
a recess for the reception of a ring seal as shown at 35 125 to
provide a vacuum tight joint to the bustle chamber vacuum source.

Since each of the bustle chambers that may be used in such an array is
substanSubjacent to the bottom surface of plate 14 and bearing
thereagainst is spacer element which is provided with an internal
passageway 21 which is adjacent recess 18 and ring 19.
Subjacent to spacer-element 20 and bearing thereagainst is a bustle
chamber element 22 which is similar in all respects to bustle chamber
element 14 Subjacent to and bearing against the lower surface of
bustle chamber element 22 is a terminal plate-like element 23 which
has an aperture 24 of substantially the same dimension and
configuration as aperture 13 of plate-like element 10.
Aperture 24 is counterbored as shown in 25 for a purpose which will be
discussed in detail later Element 23 is provided with a passageway 26
as shown.
Rectangular cross-sectioned recesses or counterbores 27 and 28 are
provided in the upper and lower surfaces of identical bustle chamber
forming elements 14 and 22 as shown Clamped within recesses 27 and 28
by means of adjacent plate-like elements 10 and 20, for example, are
the rim portions 29 of identical gas trap elements 30 Gas trap
elements 30 (as shown particularly in Fig 3) are centrally apertured
and have a frustoconical portion 31 extending from flange 29.
The internal diameter of flange 29 is substantially the same as the
internal dimension of aperture 15 of element 14 and recess 25 of
element 23, while the internal dimension of the aperture formed by
conical section 31 is slightly smaller than the external dimension of
rod-like element 3.
The gas trap elements 30 are preferably formed from a resilient
heat-resistant metallic sheet material which resists plastic
deformation even at elevated temperatures.
In order to retain the resiliency of the conical section 31 and to
permit rod-like element 3 to pass through the central aperture of the
trap element 30 while maintaining a constant frictional engagement
between element 3 and trap elements 30, spaced slits 32 are provided
in conical section 31 and extend from the aperture substantially to
flange portion 29 in a radial direction In this manner as element 3
passes through the central apertures of trap elements 30, the
converging portions 31 of the trap elements maintain a frictional
contact with the peripheral surface of element 3 The intersection of
each of these elements 30 with element 3 defines a substantially
continuous line encircling the element 3, i e each element 30
maintains a substantially continuous frictional line contact with
element 3 It is to be noted that the slits 32 are preferably formed by
a shearing operation or the like rather than a punching or slotting
operation so that, if irregularities in the surface of the rod-like
element tend to reduce its trans784,735 tially identical, it is not

considered necessary to describe other identical structures shown
associated with element 22 than the recess structure and central
aperture of the terminal end plate 23 The counterbored recess 25 in
end plate 23 is provided in order to accommodate the flexure of the
terminal gas trap 30 The dimension and configuration of aperture 24 of
plate 23 is only slightly larger than the external dimension and
configuration of element 3 in order to restrict the free flow of
atmospheric gases into the bustle chamber seals.
It will therefore be seen upon inspection that only a limited amount
of the gases of the atmosphere may flow through the restricted opening
formed between the outer periphery of element 3 and aperture 24.
Only a limited amount of these gases will pass through the extremely
small apertures 32 of trap element 30 into a first bustle chamber At
this point the vacuum pumping means in communication with the chamber
will remove a substantial portion or amount of the gas Gas flow from
the first chamber into a succeeding chamber is further restrained and
reduced in amount by the necessity of the gas having to flow through
the small apertures 32 of two more gas traps 30 In the next bustle
chamber the quantity of gas is again reduced and as the gas progresses
from chamber to chamber with corresponding reductions in amount at
each chamber, the gas pressure and consequently the amount of gas
present will become reduced to an amount within the pumping capacity
of the main vacuum chamber 1 When this predetermined point is reached
the residual gas is permitted to flow into the main vacuum chamber and
is then pumped out in the due course of the operation of the
apparatus.
Under some circumstances, it may be undesirable to permit any gas to
flow into the vacuum chamber In such a case, sufficient pumping
capacity may be provided for the final bustle chamber so that it
cooperates with the chamber's vacuum source, to maintain the vacuum of
the chamber In this circumstance the flow of gas in the annular
conduit contained in tubular element is in the direction of the bustle
chamber and away from the vacuum chamber.
While the foregoing discussion and the embodiment illustrated has been
directed to a seal for the extraction of a rod-like element from a
vacuum chamber, a substantially identical array of these same elements
may be used to insert a rod-like element into a vacuum chamber, as
suggested previously.
In both arrangements and as illustrated in the drawing, the direction
of convergence of the conical portions 31 of gas trap elements is in
the direction of motion of element 3.
The various elements comprising the seal are readily disassembled and
replaceable and, further, similar elements are interchangeable,
permitting flexibility in installation and maintenance.

A further particular practical advantage 70 of the seal of this
invention is that it may be readily altered by the addition or
subtraction of bustle chambers to fit the particular vacuum condition
requirements of a particular operation or reaction to be performed 75
in the vacuum chamber By the employment of the metallic gas trap
elements 30, a considerable variation in the number of bustle chambers
may be accomplished without greatly increasing the length of the seal
80 This is important in industrial installations where space is at a
premium and extensive structural changes in permanently installed
heavy equipment, such as a vacuum furnace, for example, cannot be
tolerated 85 While the foregoing disclosure has described the
application of the seal structure to either the continuous insertion
of a rodlike element into a low pressure chamber or the continuous
extraction of such an ele 90 ment from such a chamber, it should be
appreciated that substantially the same seal structure is equally
adapted to the insertion or extraction of a rod-like element from a
high pressure chamber In such an appara 95 tus, gas at high pressure
would be supplied by means of a pump or the like to the toroidal
bustle chambers.
In practice, of course, the number of serially arranged bustles or
pumping cham 100 bers and gas trap elements to be used in a particular
installation will depend upon several factors In general, these
factors are, the pressure desired to be maintained within the vacuum
container, the pumping 105 capacity of the vacuum source of the
container, the size and number of slits in the gas trap elements, and
the pumping capacities of the vacuum sources attached to the bustles
For purposes of this disclos 110 ure it will be assumed that the
external pressure of this system is atmospheric although it is to be
noted that the invention is not necessarily limited to use in that
pressure range 115 From the foregoing it may be seen that an efficient
vacuum sealing apparatus is provided whereby a longitudinally movable
rodlike element, particularly a hot newly cast ingot of metal, may be
extracted through a 120 wall of a vacuum container and which
cooperates with the container and the rod-like element or ingot to
substantially prevent leakage of atmospheric gases around the ingot
into the vacuum container While the 125 specific disclosure of the
invention illustrates a rod-like element or ingot having a circular or
substantially circular cross-section co-operating with a seal
structure which forms a substantially circular cylindrical 130 784,735
2 A pressure seal structure as claimed in claim 1 for a rod-like
element movable in a longitudinal direction through the aperture, in
which the gas trap elements are frusto-conical, and are arranged with
the conical portions of each of the elements converging in the
direction of longitudinal movement of the rod-like element.

3 A pressure seal structure as claimed in claim 2 having a plurality
of radially disposed slits provided in the conical portion of each of
the trap elements permitting resilient expansion of their apertures to
accommodate the passage of the rod-like element.
4 The combination of a pressure chamber, a gas pumping means for the
chamber, an aperture in a wall of the chamber, a straight rod-like
element continuously passing through and substantially filling the
aperture, and a substantially tubular seal structure as claimed in
claim 2 or 3 encompassing the aperture and closely surrounding a
portion of the outwardly projecting length of the rod-like element,
the annular spaces defined by successive pairs of the trap elements
constituting bustle chambers, and each so-defined bustle chamber being
provided with a gas pumping means.
A pressure seal structure substantially as herein described and shown
in the accompanying drawings.
J W RIDDING, Chartered Patent Agent, 64-66, Coleman Street, London, E
C 2, Agent for the Applicants.
passage, it is to be understood that these elements may be formed with
other and specifically different cross-sectional configurations
without departing from the scope of the appended claims.
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* GB784736 (A)
Description: GB784736 (A) ? 1957-10-16
Improvements in or relating to heat exchange apparatus
PATENT SPECIFICATION
784,736 Date of Application and filing Complete Specification: Feb

8,1956.
No 3931156.
Application made in United States of America on Feb 14, 1955.
Complete Specification Published: Oct 16, 1957.
Index of Acceptance:-Classes 83 ( 2) A 158; and 83 ( 4), Q( 2 A 2: 2 A
13: 4).
International Classification,:-B 23 d, p.
Improvements in or relating We, WESTINGHOUSE ELECTRIC INTERNATIONAL
COMPANY, of 40 Wall Street, New York 5, State of New York, United
States of America, a Corporation organised and existing under the Laws
of the State of Delaware, United States of America, do hereby declare
the invention, for which we pray that a patent may be granted to us,
and the method by which it is to be performed, to be particularly
described in and by the following statement: -
This invention relates to heat exchange apparatus and more
particularly to a method of manufacturing plate and tube heat
exchangers of the type used as condensers in domestic refrigerator
systems.
Refrigerant heat exchangers have been constructed in the past in which
a serpentine refrigerant carrying tube is attached to a plate member
preferably made from metal or other good heat-conducting material The
plate member presents a large surface area for efficient heat exchange
purposes and provides the necessary rigidity for the structure to
permit it to be easily handled and mounted A number of methods have
been proposed for securing the tube intimately to the plate such as is
necessary to give good heat transfer between the two Some of these
methods involve the formation of grooves on the plate member to
receive the tube, and further forming operations on the plate to cause
the plate to grip and hold the tube in place It is with this general
method of manufacture that the present invention is concerned.
The chief object of this invention is to provide an improved method of
forming a tube and plate type heat exchanger.
A further and more specific object of this invention is to provide an
improved method of forming the plate member of a plate and tube type
heat exchanger to effect efficient and uniform engagement between the
plate and tube whereby the said tube is effectively clinched on to the
plate member.
lPrice 3 s 6 d l to heat exchange apparatus With the above objects in
view, the invention resides, basically, in the method of forming a
tube and plate heat exchanger which comprises forming a groove in the
plate, working said plate to decrease the depth of said groove While
confining the regions of said plate adjacent said groove whereby the
portions of said plate which form the upper walls of the groove and

other portions of said plate immediately contiguous to said first
named plate portions are formed into a double wall rib at either edge
of said groove, subsequently assembling the tube in the groove thus
formed, with the said double wall ribs, and acting on said ribs to
clinch them over said tube.
In order that the invention may be more clearly understood and readily
carried into effect, reference will now be made to the accompanying
drawings, in which: Fig 1 is a broken elevational view of a plate and
tube type heat exchanger manufactured in accordance with this
invention; Fig 2 is an end view of the heat exchanger shown in Fig 1;
Fig 3 is an enlarged fragmentary sectional view showing the initial
groove forming operation on the heat exchanger plate member; Fig 4 is
an enlarged fragmentary sectional view showing one of the die
combinations used in a further step in the forming of the heat
exchanging plate; Fig 5 is another view of the die combination shown
in Fig 4, and showing the forming operation performed by this die
combination; Fig 6 is an enlarged fragmentary sectional view showing
the clinching operation performed on the plate member to clamp the
tube in place; and Fig 7 is a fragmentary sectional view showing a
bending operation performed on the plate and tube members.
In Figs 1 and 2 of the drawings there is shown a plate and tube type
heat exchanger made in accordance with this invention and 2 784,736
having a configuration suitable for use as a condenser for a domestic
refrigerating unit.
As shown in Fig 1, the heat exchanger consists of a serpentine
refrigerant carrying tube 12 secured to a plate member 13 The tube 12
is held in place on the plate 13 by virtue of the manner in which the
plate 13 is formed about the straight portions 14 of the tube as will
be explained more fully hereinafter The U-shaped connecting portions
16 of the tube 12 extend beyond the longitudinal edges of the plate 13
The longitudinal edges of the plate 13, as well as the connecting
portions 16 of tube 12, are curved out of the plane of the body of the
plate as shown in Fig 2 and have flanged edge members 17 attached
thereto which extend the full length of the plate 13 The curved plate
13 together with the edge members 17 form a channel structure suitable
for mounting on the back of a domestic refrigerator, and mounting
holes 18 are provided in the edge member 17 for that purpose.
The heat exchanger is manufactured in the following manner; A flat
plate of good heat conducting material, such as steel, and having
suitable dimensions is first placed between the two die members
indicated at 19 and 21 in Fig 3 and a plurality of grooves or
depressions 22 are formed across the width thereof, one at a time In
this operation a press having a single die combination of the
configuration shown in Fig 3 is utilized and the plate 13 is fed

through the press in predetermined steps of movement to space the
grooves along the plate 13.
In the operation illustrated in Fig 3, the plate 13 is formed to
provide the grooves 22 with substantially straight upper side wall
portions 23 The depth of the groove 22, from the upper edges 24 of the
side walls 23 to the bottom of the groove is greater than the outside
diameter of the tube subsequently to be positioned in the groove The
plate 13 is also formed with portions 27 thereof which are contiguous
to the groove side walls 23 and displaced from the plane of the
deformed portions of the plate 13.
A gradually sloping region 28 joins the contiguous portions 27 to the
undeformed portion of the plate 13 It is not essential to this
invention that plate portions 27 be displaced from the plane of plate
13, as shown, but rather the groove top edge 24 may lie in the same
plane as the undeformed portions of plate 13 The purpose of this
additional deformation of plate portions 27 and 28 is to ensure that
all of the tube 14 will lie on one side of the plate 13 in the
finished heat exchanger This leaves one surface of the plate 13 free
of protuberances and simplifies attachment of the plate 13 to edge
members 17.
After the above described initial grooving operation has been
performed on the plate 13, the plate is placed in a press having a
plurality of die combinations like the one shown in Figs 4 and 5 Figs
4 and 5 show a die combination for working a single 70 groove of the
plate 13 and it is to be understood that in this operation all grooves
are preferably worked simultaneously in a press containing a die
combination for each groove By working all grooves of the plate 75 13
simultaneously, any inaccuracies in the spacing between the grooves
resulting from the initial individual groove forming operation can be
corrected.
In Fig 4, the die members for performing 80 the second forming
operation on the plate 13 are shown in the position which they assume
upon initial contact with the plate 13 The portions of plate 13
adjacent to the groove 22, including sloping portions 28, are 85
gripped between upper and lower holding dies 29 and 31 The faces of
die members 29 and 31 are so constructed as to grip these portions of
the plate 13 and retain the shape imparted thereto during the initial
forming 90 operation Plate portions 27, contiguous to the groove 22,
are however not confined between the holding die The upper holding die
member 29 is slotted at 32 to receive a follower plunger 33, the lower
end of 95 which projects beneath the face of die 29 and is shaped to
fit into the plate groove 22.
The follower plunger 33 is biased downwardly with respect to die
member 29 by means of springs 34, only one of which is 100 illustrated

The springs 34 are carried in a recess 35 in a back-up plate 36
rigidly attached to the die member 29 and transmit force to the
follower plunger 33 through a T-shaped bar 37 The lower holding die
105 31 is also slotted at 38 to receive a plunger die 39 having a
semi-circular channel 41 in its upper surface adapted to receive the
bottom wall of plate groove 22 The plunger die 39 is rigidly attached
to a lower backing 110 plate 42 A number of springs (not shown) are
interposed between the lower holding die 31 and the lower backing
plate 42 to move these die members away from one another as shown in
Fig 4 when the forming 115 press is open.
As mentioned previously, Fig 4 illustrates the position of the die
members at the beginning of the second forming step It can be seen
that the follower plunger die 33 120 has been forced into plate groove
22 and is clamping the bottom wall of groove 22 against the lower
plunger die 39 This initial engagement of the grooved plate 13 by the
die members of this forming opera 125 tion positions the grooves 22
with respect to one another and corrects any variations in spacing
between the grooves 22 which may have occurred during the initial
groove forming operation when the grooves were 130 784,736 784,736
formed individually The importance of having the grooves properly
positioned with respect to one another can be appreciated when it is
understood that additional forming operations are to be performed on
the plate by dies designed to work all of the grooves simultaneously,
and accurate spacing of the grooves is essential for such simultaneous
forming operations Furthermore, a preformed serpentine tube is to be
placed in these grooves in a subsequent operation If the grooves are
improperly spaced from one another, difficulty may be experienced by
the operator in assembling the preformed tube.
Further forming of the plate takes place as the press is closed to
bring the die members 31 and 42 together Fig 5 illustrates the
positions assumed by the die members shown in Fig 4 when the press is
completely closed and the plate member 13 is worked It can be seen
that the closing of the press has forced lower plate member 42 into
engagement with the lower holding die 31, moving plunger die 39
upwardly in slot 38 The lower end of follower plunger 33 holds the
bottom of groove 22 in channel 41 of plunger die 39 to retain the
smooth curvature of the bottom of groove 22 as the plate material
defining the groove is forced upwardly by plunger die 39 Follower
plunger 33, carried by the upper holding die 29, is forced upwardly
against the action of spring 34 This upward movement of the plate
material in the groove 22 pulls the unconfined plate portions 27 up
into engagement with curved projections 43 on the face of holding die
29 As plate portions 27 engage projections 43 and movement of the
groove plate material continues upwardly, the upper walls 23 of the

groove are rolled outwardly, forming a sharp break at 44.
This rolling or breaking of the upper groove wall 23 shortens the
depth of the groove 22 and forms from the upper walls 23 and plate
portions 27 double wall ribs 46 at either side of the groove 22 The
plate 13 is thus prepared for the attachment of a tube.
The plate 13 is next placed in another press for performance of the
clinching operation illustrated in Fig 6 A preformed serpentine
section of tube 12 is assembled with the straight portions 14 thereof
lying in grooves 22 The die members in this operation are shaped as
shown in Fig 6, in which the lower die 47 has a surface configuration
such as to receive and support a grooved portion of plate 13 The upper
die 48 is constructed with a pair of projections having oppositely
inclined faces adapted to act on the upstanding ribs 46 adjacent
groove 22 to bend or clinch these ribs 46 over the exposed surface of
tube 14 to clamp the tube in place within groove 22.
Again this clinching operation is performed on all grooves
simultaneously, only the die member for one groove being illustrated.
With the tube 14 thus attached to the plate 13, this assembly is
placed in a bending die combination illustrated in Fig 7, in which the
edges of the plate 13 are bent upwardly, giving the plate and tube
assembly a channel shape configuration.
The upper and lower die members 51 and 52 for performing this
platebending operation are not illustrated in detail It is to be
understood, however, that these die members 51 and 52 are provided
with surface configurations such as to prevent damage, during the
bending operation, to the plate grooves 22 and the tube 12 clamped
therein.
Such dies may be constructed from knowledge presently available in the
art and no detailed description is deemed necessary here After the
plate member 13 is removed from the bending dies 51 and 52, the edge
plates 17 shown in Figs 1 and 2 are attached thereto by welding or
other suitable means to complete the heat exchanger.
From the foregoing it will be apparent that this invention provides a
novel and improved method of attaching a tube to a plate in heat
exchange apparatus It will further be appreciated that the novel steps
employed in forming the plate to receive the tube result in a simple,
yet effective, manner for clamping the tube in place in the groove of
the plate.
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* GB784737 (A)
Description: GB784737 (A) ? 1957-10-16
Flame tip or nozzle for welding blowpipes and method of making it
PATENT SPECIFICATION io 4574
%t Date of Application and filing Complete Specification: April, 17,
1956.
No 11701/56 Application made in Australia on April 20,1955.
" 7 -',Complete Specification Published: Oct 16, 1957.
Index at Acceptance:-Class 83 ( 2), A 113.
International Classification:-B 23 p.
Flame tip or nozzle for welding blowpipes and method of making it We,
THE BRITISH OXYGEN COMPANY Li Mi TED, a British Company of,
Bridgewater House, Cleveland Row, St James's, London, S.W 1, do hereby
declare the invention, for which we pray that a patent may be granted
to us, and the method by which it is to be performed, to be
particularly described in and by the following statement: -
It has been proposed to make tapered nozzles or flame tips for welding
blowpipes by swaging one end of a tube Hitherto, however, such swaging
operations, because of the extensive tube diameter reduction involved,
have caused formation of small ripples or waves in the internal
surfaces of the tubular tip, and these, in the final stages of swaging
frequently fold or otherwise become accentuated thus causing
undesirable irregularities in the bore surface.
These irregularities are particularly objectionable as they prevent
obtaining what is usually referred to as a good " gas stream, namely,
one of uniform delivery due to absence of turbulence and the like The
object of the present invention is to produce a tip by swaging in such
a manner that the tip is free of the objectionable feature referred to
above, and also in a manner which ensures the final outlet nozzle bore
to be perfectly smooth, straight and otherwise possessed of all the

accuracy obtainable by first-class machining operations, as distinct
from swaging or the like.
According to this invention a welding blowpipe tip is made from a
piece of malleable tube and an insert tip element or sleeve which
during the course of manufacture becomes fixedly united in what
becomes the outlet end of the tube The inserted tip element comprises
a cylindrical open-ended sleeve whereof the bore is drilled or
otherwise accurately formed to the required nozzle outlet size, or it
may be drilled to some greater size and subsequently brought lPrice 3
s 6 d l to the required final size by a swaging operation in which the
bore diameter reduction is not sufficient to involve the swaging
disabilities referred to above The external wall surface of the
inserted sleeve is furnished with one or more peripheral grooves or
beadings for anchorage purposes as referred to later herein.
The method according to the present invention comprises the steps of:
inserting a tip sleeve, as a close fit, inside the outlet end of a
blowpipe tube; inserting a mandrel, whereof the lateral dimensions are
the same as those required of the bore of the finished tip, inside the
inserted sleeve; and swaging the outlet end of the tube (with the
sleeve in it) thereby causing the tube to grip the sleeve tightly and
leave the bore of said sleeve shaped in close correspondence with the
outside of the mandrel.
Examples of the invention are illustrated in the drawings herewith All
the figures of the drawings are medial cross-sectional views.
-Fig shows the outlet end of a blowpipe tube and -a tip sleeve ready,
for insertion therein Fig 2 repeats Fig 1 but with the sleeve
inserted.
Fig 3 repeats Fig 2 but with the swaging mandrel inserted.
Fig 4 is substantially the same as Fig 3 but illustrates a minor
modification.
Fig 5 shows a finished flame tip.
Fig 6 shows part of a blowpipe tube to illustrate another minor
modification.
The outlet end 7 of the blowpipe tube may be preliminarily swaged as
indicated at 8 The tip sleeve 9 is made as a close fit for the bore of
the end 7 and is inserted therein as shown in Fig 2 The sleeve is
furnished with means which assist its eventual anchorage within the
blowpipe tube by swaging These means are preferably circumferential
grooves 10 Obviously, 1 i'' ' Price 33 p an, Athey could be projecting
circumferential beadings, but grooves, such as 10, are better for
manufacturing simplicity.
The finished bore of the sleeve may be plain cylindrical (as shown in
Fig 1) or its upstream end may be countersunk, doubly countersunk,
rounded, or otherwise shaped as may be required The sleeve may be

initially bored as of the required final size as shown in Fig 4, or it
may be first bored somewhat larger than the required final size as
shown in Figs 1-3 and as explained below.
In Fig 3 a sleeve is shown which has its bore oversize and entered by
a mandrel 11.
Upon circumferentially applied compressive swaging, the metal of the
tube is forced into the grooves 10 and the bore of the sleeve 9 is
forced into conformity with the mandrel as shown in Fig 5.
In Fig 4 a sleeve is shown whereof the bore has been initially formed
as of the required final dimensions Upon the mandrel 11 being entered,
as shown, and followed by swaging as referred to above, the result is
also as shown in Fig 5.
Fig 6 shows the outlet end of a blowpipe tube which is the same as
those described above except that a counterbore 12 is provided to
receive a sleeve (such as 9) Provision of such a counterbore
facilitates sleeve insertion, by providing a stop against which the
sleeve may abut, and also helps to keep the sleeve in position during
swaging.
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