GB2162446A

GB2162446A - Manufacturing components for gas fired appliances

Info

Publication number: GB2162446A
Application number: GB08419086A
Authority: GB
Inventors: Clive Newton Garey; John Norris
Original assignee: TI GAS SPARES Ltd
Current assignee: TI GAS SPARES Ltd
Priority date: 1984-07-26
Filing date: 1984-07-26
Publication date: 1986-02-05
Also published as: GB8419086D0; GB2162446B

Abstract

A gas tap body is formed from a tubular member which is shaped by applying fluid pressure to the interior thereof. The tubular member is located in a die while the fluid pressure is being applied. The tube may be flattened and bent before the fluid pressure is applied. Several gas tap bodies may be formed from a single tubular member and, in the particular case in which the bodies are generally L- shaped, the tubular member is bent into a serpentine configuration before the fluid pressure is applied. <IMAGE>

Description

SPECIFICATION Components for gas fired appliances The present invention relates to components for gas-fired appliances and to the manufacture of such components. The invention relates more especially to the manufacture of gas tap bodies for use, in particular, on cookers.

A gas cooker hot plate incorporates a respective gas tap for each burner, for controlling the supply of gas to the burner from a common gas rail on which the taps are mounted. Each tap comprises a suitably-shaped body, housing a valve operated by a spindle which projects from the tap body and carries an operating knob. The particular shape and size of a tap body are to a large extent determined by the cooker hot plate in which it is to be used, and tap bodies having a desired shape and size are conventionally produced by such methods as die casting, stamping, extrusion, fabrication etc.

It is an object of the present invention to enable a reduction in the cost of producing a gas tap body, or similar component, to be achieved.

The present invention provides a method of manufacturing a component for a gas-fired appliance by forming the component from a tubular member, the method comprising the step of shaping the tubular member by applying fluid pressure to the interior thereof. The tubular member may be located in a die while fluid pressure is applied to the interior thereof, the die defining the required final shape of the tubular member.

The method may include the step of flattening the tube prior to applying fluid pressure to the interior thereof and may also include the step of bending the tube prior to applying fluid pressure to the interior thereof in which case the tube is flattened before it is bent.

Advantageously, a plurality of components are formed from a single tubular member, the components being separated from each other when the tubular member has been shaped. The components may be formed end-to-end along the length of the tubular member: in an embodiment of the invention, each component is generally L-shaped and the tubular member is bent into a serpentine configuration prior to applying fluid pressure to the interior thereof.

When the component is a gas tap body, the fluid pressure may be applied to the tubular member to shape the member to receive a valve member for controlling the flow of gas between an inlet and an outlet in the tap body.

The present invention also provides apparatus for manufacturing a component for a gas-fired assembly from a tubular member, the apparatus comprising a die defining the desired shape of the component, the die being arranged to receive the said tubular member, and means for applying fluid pressure to the interior of the tubular member to shape the tubular member when located in the die.

The present invention further provides a component for a gas-fired appliance, which component comprises a tubular member shaped by the application of fluid pressure to the interior of the tubular member. When the component is a gas tap body, it is shaped to receive a valve member to control the flow of gas from an inlet in the body to an outlet in the body. The body may further be shaped to be mounted on a gas rail to convey gas from the rail to a burner of the cooker.

By way of example, a gas tap body and the method of producing it will now be described with reference to the accompanying drawings in which: Figure 1 shows, in cross-section, a gas tap mounted on a gas rail; Figure 2 shows a similar cross-section through a gas tap body; Figures 3 and 4 are views in the direction of the arrows Ill and IV in Fig. 2; and Figure 5 illustrates a stage in the production of a gas tap body.

The tap shown in Fig. 1 has a tubular body 1 bent through approximately 904 so that it is generally L-shaped. A gas inlet 2 is formed in the tube wall in a vertically-extending leg of the Lshaped body and the end of the bore in the other, horizontally-extending, leg of the body constitutes a gas outlet 3. The body 1 is mounted on a horizontally-extending gas rail 4 of a cooker hot plate (not shown) so that the inlet 2 is in communication with the interior of the rail.

A suitably-shaped valve member 5 located in the bore of the tubular body 1 controls the flow of gas from the gas rail 4 through the inlet 2 to the outlet 3 and thence via the conventional injector and mixer tube (not shown) to a burner of the hot plate.

Operation of the valve member is controlled by a spindle 6 which projects from the upper end of the vertically-extending leg of the tap body 1. It will be understood that the spindle 6 would project through to the upper side of the horizontal surface of the cooker hot plate and would carry a control knob (not shown). Movement of the spindle is guided in the conventional manner by a niting pin 7 located in the niting groove 8 formed in the tap body 1. The shape of the niting groove 8 is shown in greater detail in Fig. 4.

When the valve member 5 is in its unoperated (tap closed) position, shown in the drawings, the niting pin 7 is located at the top of the vertical arm 10 of the niting groove 8. The gas inlet 2 is only partly covered by the valve member 5 but gas flow to the outlet 3 or leakage to the spindle end of the tap is prevented by seals 11,12 one on each side of the valve member.

To operate the valve member 5 to open the tap it is necessary first to depress the spindle 6 against the action of a return spring 9 and bring the niting pin 7 to the bottom of the vertical arm 10 of the niting groove. The seal 11 has now been moved out of engagement with the tap body but the inlet 2 is now closed by the valve member 5. Thereafter the spindle 6 can be rotated to move the niting pin along the horizontal arm 13 of the niting groove, so rotating the valve member 5 to bring the shaped portion thereof into co-operation with the inlet 2 and permit an increasing flow of gas to the outlet 3.

The shape of the tap body is shown in greater detail in Figs. 2 and 3. As already described, the body is tubular but the vertically-extending leg 20 is of greater diameter both internally and externally than the leg 21 which extends generally horizontally. The leg 20 is of constant crosssection until immmediately above the junction with the leg 21 at which point it flares out at an angle approximately 30 to form a bowl-shaped portion 22 at the bottom of the vertical leg, in which the return spring 9 of the valve member 5 (Fig. 1) is seated. The leg 21 extends sideways from the bowl-shaped portion and runs initially upwards at an angle of 45 before extending substantially horizontally to the outlet 3.Over the upwardly-inclined portion of the leg 21 the cross-section of the leg decreases to become substantially circular but of smaller diameter than the leg 20 and then remains constant to the outlet end.

Typically, the tap body has the following dimensions: maximum overall height: 37 mm maximum overall length: 33 mm internal diameter of leg 20: 9 mm internal diameter of leg 21: 4 mm minimum wall thickness: 1 mm.

The tap body is formed from a simple constant diameter tube which is brought to the required shape through the application of fluid pressure to the interior of the tube. In greater detail, the tube is first flattened, then bent through 90 , and then re-inflated by the application of fluid pressure to the interior of the tube to produce the desired shape shown in Fig. 2. The initial flattening of the tube facilitates the formation of the 90 bend and the tube can then be placed in an appropriately-shaped die to be re-inflated. The fluid pressure for re-inflating the tube is applied at one end of the tube, the other end being plugged.

Following re-inflation to the desired shape, the niting groove 8 and gas inlet 2 are formed in the body wall and, the tap body is then ready for attachment to the gas rail 4 as shown in Fig.

1. Any machining or processing of the bore of the leg 20 that may be required to ensure an accurate fit of the valve components is carried out following attachment of the required number of tap bodies to the gas rail: in this way, accurate alignment of the tap spindles relative to each other can be achieved.

It may be possible, depending on the design of the tap body, for the gas inlet to be partlyformed during the fluid inflation of the tube and completed by, for example, drilling, punching or shearing before the body is attached to the gas rail.

When the valve components have been inserted in the leg 20 of the tap body the spindle end of the body wall may be turned over as indicated at 23 in Fig. 1 and shown in dotted lines in Fig. 2: this will ensure that the components are retained in the event of the niting pin 7 being dislodged.

It will be appreciated that, although the production of one design of L-shaped tap body has been described, a similar method could be used to produce L-shaped tap bodies of other designs or, indeed, tap bodies of other shapes. For example, a tap body have a generally straight tubular form could be produced using the fluid inflation technique described above although, in this case, the the step of bending the tube prior to inflation would be omitted. In general, the shape of the tap body and, within that shape, its particular size and design will be determined by the design of the cooker hot plate in which it is to be used.

The tube from which the tap body is formed may be of any suitable material, for example mild steel, and the wall thickness of the tube should be greater than the desired minimum wall thickness in the tap body. For example, if it is required that the tap body should have a minimum wall thickness of 1 mm then it may be found that an original wall thickness of as much as 2 mm is required in the tube from which the body is formed, particularly when an Lshaped tap body similar to that shown in Fig. 2 is being produced: in the case of a straight tubular body, an original wall thickness of 1.2 to 1.3 mm may be sufficient.

Any appropriate fluid may be used to reinflate the flattened tube to the desired shape. Having regard to safety, a preferred fluid is soluble oil. The pressure required to reinflate the tube will depend on the tube material and body shape required: for example, in the case of the mild steel tube described above, a pressure of the order of 8000 psi built up from zero in approximately 2 to 3 seconds could well be sufficient when a straight tubular body is being produced but, for an L-shaped body as shown in Fig. 2, a pressure as high as 30,000 psi may be required. The pressure is appropriately applied from a pressure intensifier connected to one end of the tube and it has been found that heat generated during inflation of the tube is readily dissipated in the pressurizing fluid.

Conveniently, a plurality of valve bodies is shaped in a single operation from one length of tube. This is illustrated in Fig. 5 for the particular case of a plurality of L-shaped bodies and is achieved as follows: The tube is inflated as already described and is then bent into a serpentine configuration as shown in the drawing. The tube shown in Fig. 5 is formed with three complete 360 bends 50, 51 and 52 each comprising four 90 turns and being of sufficient length to form four tap bodies .0.... d, 51 a. . d and ..... . d. The flattened, serpentine tube is then placed in an appropriately-shaped die and reinflated, as already described, to yield a plurality of tap bodies connected end-to-end, which can then be separated and finished.Fig. 5 shows the tube following re-inflation to give twelve tap bodies connected end-to-end.

For the purposes of illustration the tap bodies shown in the right-hand half of Fig. 5 are of a slightly different shape to those shown in the left-hand half: the latter are of the shape shown in Fig. 2 but the former have a wider outlet 3, the shape of the outlet depending on whether it is to be provided with an internal or an external connection. Normally, of course, the tap bodies would all be formed with the same shape.

Fig. 5 illustrates that the finished design of the tap body can be varied while still employing the fluid inflation method of production described above and indicates that, as already mentioned, other shapes could be produced by this method. It will further be appreciated that the method is not restricted to the production of gas tap bodies but could be used to produce other components particularly for gas fired appliances, for example heat exchangers.

The method described enables the production of a gas tap body to be simplified and the amount of material employed, in the form of the straight cylindrical tube, to be minimized thereby enabling substantial reductions in cost to be achieved.

Claims

1. A method of manufacturing a component for a gas-fired appliance by forming the component from a tubular member, the method comprising the step of shaping the tubular member by applying fluid pressure to the interior thereof.

2. A method as claimed in claim 1, in which the tubular member is located in a die while fluid pressure is applied to the interior thereof, the die defining the required final shape of the tubular member.

3. A method as claimed in claim 1 or claim 2, including the step of flattening the tube prior to applying fluid pressure to the interior thereof.

4. A method as claimed in any one of the preceding claims, including the step of bending the tube prior to applying fluid pressure to the interior thereof.

5. A method as claimed in claim 4 when appendant to claim 3, in which the tube is flattened before it is bent.

6. A method as claimed in claim 4 or claim 5 for manufacturing a generally L-shaped component, in which the tube is bent to a general-shape prior to applying fluid pressure to the interior thereof.

7. A method as claimed in any one of the preceding claims, in which a plurality of components are formed from a single tubular member, the components being separated from each other when the tubular member has been shaped.

8. A method as claimed in claim 7, in which the components are formed end-to-end along the length of the tubular member.

9. A method as claimed in claim 8, in which each component is generally L-shaped and the tubular member is bent into a serpentine configuration prior to applying fluid pressure to the interior thereof.

10. A method as claimed in any one of the preceding claims, in which the tubular member is formed from mild steel.

11. A method as claimed in any one of the preceding claims, in which the wall thickness of the tubular member is greater than the required wall thickness of the component.

12. A method as claimed in any one of the preceding claims for forming a gas tap body, including the step of finishing the internal surfaces of at least one part of the tubular member for co-operation with a valve member.

13. A method as claimed in any one of claims 1 to 12 for forming a gas tap body, the fluid pressure being applied to the tubular member to shape the member to receive a valve member for controlling the flow of gas between an inlet and an outlet in the tap body.

14. A method as claimed in claim 13, in which the fluid pressure is applied to the tubular member to form the gas outlet at one end thereof, the method also including the step of forming the gas inlet in the wall of the shaped tubular member.

15. A method as claimed in claim 14, further including the step of mounting the tap body on a gas rail to supply gas to the inlet.

1 6. A method as claimed in claim 14 or claim 15, further including the step of locating a valve member in the shaped tubular member to control gas flow from the inlet to the outlet, with a valve operating member extending from the said other end of the shaped tubular member.

17. Apparatus for manufacturing a component for a gas-fired assembly from a tubular member, the apparatus comprising a die defining the desired shape of the component, the die being arranged to receive the said tubular member, and means for applying fluid pressure to the interior of the tubular member to shape the tubular member when located in the die.

18. Apparatus as claimed in claim 17, in which the die is arranged to receive the tubular member in flattened form.

19. Apparatus as claimed in claim 17 or claim 18, in which the die is shaped to receive the tubular member in bent form.

20. A component for a gas-fired appliance, when made by a method as claimed in any one of the claims 1 to 16 or by apparatus as claimed in any one of claims 17 to 19.

21. A component for a gas-fired appliance, which component comprises a tubular member shaped by the application of fluid pressure to the interior of the tubular member.

22. A component as claimed in claim 21, having a through-bore therein.

23. A component as claimed in claim 21 or claim 22, which is substantially tubular with at least one bend therein.

24. A component as claimed in any one of claims 21 to 23, which is shaped to receive a valve member.

25. A gas tap body as claimed in claim 24, the body being shaped to receive the valve member to control the flow of gas from an inlet in the body to an outlet in the body.

26. A tap body as claimed in claim 25, for a gas cooker, the body shaped to be mounted on a gas rail to convey gas from the rail to a burner of the cooker.

27. A tap body as claimed in claim 25 or claim 26, the body being generally L-shaped with one leg of the L-shape containing the gas inlet and being shaped to received the valve member and the other leg containing the gas outlet.

28. A gas tap including a body as claimed in claim 27, a valve member located in the said one leg of the L-shape and an operating member for the valve member projecting from the end of the leg.

29. A method as claimed in any one of claims 1 to 16, substantially as described herein.

30. A method as claimed in any one of claims 7 to 9, substantially as described herein with reference to, and as illustrated by, Fig. 5 of the accompanying drawings.

31. A gas tap body substantially as described herein with reference to, and as shown in, Figs. 2 to 4 of the accompanying drawings.

32. A gas tap substantially as described herein with reference to, and as shown in, Fig. 1 of the accompanying drawings.

CLAIMS Amendments to the claims have been filed, and have the following effect: Claims 1 to 32 above have been deleted or textually amended.

New or textually amended claims have been filed as follows:

1. A method of manufacturing a gas tap body by forming the body from a tubular member, the method comprising the step of shaping the tubular member by applying fluid pressure to the interior thereof.

3. A method as claimed in claim 1 or claim 2, including the stop of flattening the tube prior to applying fluid pressure to the interior thereof.

6. A method as claimed in claim 4 or claim 5 for manufacturing a generally L-shaped component, in which the tube is bent to a general L-shape prior to applying fluid pressure to the interior thereof.

7. A method as claimed in any one of the preceding claims, in which a plurality of gas tap bodies are formed from a single tubular member, the bodies being separated from each other when the tubular member has been shaped.

8. A method as claimed in claim 7, in which the bodies are formed end-to-end along the length of the tubular member.

9. A method as claimed in claim 8, in which each body is generally L-shaped and the tubular member is bent into a serpentine configuration prior to applying fluid pressure to the interior thereof.

11. A method as claimed in any one of the preceding claims, in which the wall thickness of the tubular member is greater than the required wall thickness of the body.

12. A method as claimed in any one of the preceding claims, including the step of finishing the internal surfaces of at least one part of the tubular member for co-operation with a valve member.

13. A method as claimed in any one of claims 1 to 12, the fluid pressure being applied to the tubular member to shape the member to receive a valve member for controlling the flow of gas between an inlet and an outlet in the tap body.

16. A method as claimed in claim 14 or claim 15, further including the step of locating a valve member in the shaped tubular member to control gas flow from the inlet to the outlet, with a valve operating member extending from the said other end of the shaped tubular member.

17. Apparatus for manufacturing a gas tap body from a tubular member, the apparatus comprising a die defining the desired shape of the body, the die being arranged to receive the said tubular member, and means for applying fluid pressure to the interior of the tubular member to shape the tubular member when located in the die.

20. A gas tap body when made by a method as claimed in any one of claims 1 to 16 or by apparatus as claimed in any one of claims 17 to 19.

21. A gas tap body comprising a tubular member shaped by the application of fluid pressure to the interior of the tubular member.

22. A gas tap body as claimed in claim 21, having a through-bore therein.

23. A gas tap body as claimed in claim 21, or claim 22, which is substantially tubular with at least one bend therein.

24. A gas tap body as claimed in any one of claims 21 to 23, which is shaped to receive a valve member.

26. A gas tap body as claimed in claim 25, for a gas cooker, the body being shaped to be mounted on a gas rail to convey gas from the rail to a burner of the cooker.

27. A gas tap body as claimed in claim 25 or claim 26, the body being generally L-shaped with one leg of the L-shape containing the gas inlet and being shaped to receive the valve member and the other leg containing the gas outlet.