GB1600031A - Pressure cooker relief valve assembly and pressure cookers incorporating such assemblies - Google Patents

Description

(54) PRESSURE COOKER RELIEF VALVE ASSEMBLY AND PRESSURE COOKERS INCORPORATING SUCH ASSEMBLIES (71) We, THE PRESTIGE GROUP LIMITED, a British Company of Prestige House, 14-18 Holborn, London ECiN 2LQ, 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 cooker relief valve assembly and to a pressure cooker incorporating such an assembly.

Pressure cooker relief valves are well known in themselves and can take various forms, however they usually comprise a valve member and a valve seating one of which acts against the other under pressure of biasing means to close a valve port. Thus, the valve member or the valve seating may be arranged to move and the biasing means can be in the form of a spring or other resilient device or can be provided by weights. Such relief valves are usually, although not always, placed in the removable lid of the pressure cooker in which they are used. In a well known type of relief valve two or more weights are provided so that the pressure in the cooker can be varied and the arrangement is such that when the pressure reaches a predetermined value, according to the particular weight, the weight is lifted and the pressure released.

It is desirable to be able to relieve the pressure within a pressure cooker when cooking is finished to prevent injury when the lid is opened and it is known to provide means for relieving the pressure of the biasing means on the relief valve by, for example, removing the weights or lifting the weights by means of a pivoted lever. A disadvantage with previous arrangements is that when the pressure biasing means are lifted there is a rapid escape of steam and if manual movement, for example, of the weights is required the operator can be scalded.

Again with arrangements utilising a pivoted lever the mechanism is cumbersome and unattractive and if it is to be housed within a casing it requires a casing of large dimensions.

According to the present invention a pressure cooker relief valve assembly comprises a relief valve having a valve member and a valve seating one of which acts against the other under the pressure of biasing means to close a valve port and which can be opened by a predetermined fluid pressure within the cooker and a valve operating member, movement of which in a substantially linear direction and/or in a single plane actuates means for relieving the pressure of the biasing means, said means comprising a wedge which is moved beneath the biasing means by movement of the operating member, and means for controlling the operating member from a point spaced away from the valve member.

Thus, with the construction set forth above the assembly can be located on the lid of a pressure cooker and located so that the control means can be, for example, adjacent the handle of the cooker and be spaced away from the valve member so that when pressure is relieved the chances of an accident are reduced. Moreover, by using an operating member which has movement in a substantially linear direction and/or in a single plane a low housing for the assembly can be contrived thus producing an attractive cooker.

Preferably the wedge is carried on the operating member and in a convenient construction the operating member is in the form of a flat plate on which two or more wedges are provided.

Thus, in a construction in which the biasing means is provided by a weight the wedges can be arranged to slide beneath it to lift the weight to relieve the pressure.

As mentioned above if a weight is used then additional weights can also be provided to vary the biasing pressure and the construction of the weights can be as set forth in the Applicants' U.K. Patent Specification No. 1 524 750.

Preferably the relief valve is located in a housing having a gas escape opening through which gas escaping through the valve is directed and this gas escape opening can have an outlet facing away from the means for controlling the operating member.

The valve operating member and the means for controlling it may also be located in the housing, an operative part of the control means extending out of the housing.

The means for controlling movement of the valve operating members may comprise an angularly movable element which acts against the operating member to cause it to move linearly or in a single plane when the element is rotated.

Thus, the element may be in the form of a control knob or lever provided with a cam surface which bears against the operating member and if required the operating member can be resiliently biased towards the cam surface.

The biasing can be arranged so that the operating member tends to move to a position in which the relief valve is opened.

The control knob or lever may conveniently have a ratchet to bias it towards two or more predetermined operative positions and this control knob or lever can be arranged to extend out of the housing so that it visually resembles a switch.

If desired means for controlling the valve operating member may be provided which can cause the valve to open gradually either by a series of positions or a variable number of positions.

The invention also includes a pressure cooker incorporating a relief valve assembly as set forth above.

If desired the operation of the operating member could be achieved by means of a timer in the manner set forth in the Applicants' copending British Patent Application No. 22613/ 77 filed 27 May 1977, Serial No. 1600032.

The invention can be performed in many ways but one embodiment will now be described by way of example and with reference to the accompanying drawings in which: Figure 1 is a part cross-sectional side elevation of a pressure cooker incorporating the present invention Figure 2 is a plan view of the assembly shown in Figure 1, Figure 3 is a plan view of the operating member and its associated parts, Figure 4 is a plan view from beneath of a base plate, Figure 5 is a part sectional view of part of the assembly.

As shown in the drawings a pressure cooker comprises a main body portion indicated by reference numeral 1 which has a handle 2. A lid 3 is arranged to clamp onto the body portion 1 and has a handle 4 which is arranged to be in alignment with the lower handle 2 when the lid is in the closed position. A pressure relief assembly indicated generally by reference numeral 5 is provided on the lid 3 and has a relief valve indicated generally by reference numeral 6 which is located at the centre of the circular lid 3.

The valve 6 is of known type and has a seating 7 held in position by a wing nut 8 within the lid 3. A port 9, extends through the seating 7 (Figure 5) and this can be closed by a valve member provided by a needle (not shown). The upper end of the needle is fixed to a lower weight 10 on which are carried two further weights 11 and 12. The arrangement is such that the upper weight 11 can be removed to allow removal of the middle weight 12 and it can then be replaced thus allowing the pressure of the biasing means which are provided by the weights to be varied. As mentioned above this valve is of known kind. A cover (not shown), made from a plastics material, can be provided to surround the weights and knob 13 is connected to the lower weight 10 to allow for removal when adjusting weights or cleaning.

If desired the construction of this valve could be as set forth in the Applicants' British Patent Specification 1 524 750.

In use the appropriate weights 11 and 12 are provided on the lower weight 10 and the weights maintain their biasing pressure until the pressure within the pressure cooker is such that it is sufficient to lift the weights thus lifting the needle (not shown) and anowing the pressure to escape through the port 9 and thus the desired temperature/pressure conditions are maintained in the vessel.

The valve seating 7 has a flange 14 which overlaps the edges of an opening 15 provided in a base plate 16 which is most clearly shown in Figures 3,4 and 5. This base plate 16 extends to the outer edge of the lid 3 where a retaining spring 17 (see Figures 1 and 5) attached thereto engages beneath a lip 18 provided on the handle 4. The plate is held in position by the wing nut 8 engaging a threaded portion 19 on the valve seating 7 an '0' ring 20 being provided between the plate 16 and the lid 3 to ensure a sealing fit. This base plate 16 therefore provides a secure base for apparatus for controlling the relief valve. Located above the base plate 16 is an operating member provided by a slider plate 21 which has an opening 22 which surrounds the valve seating 7 and which is of elongated shape to allow movement relative thereto.A wedge 23 is formed in the plate on each side of the opening 22 and they are shaped so that if the plate 21 is moved to the right, as shown in the drawings, the wedges 23 will engage beneath the lower surface of the weight 10 of the valve and thus cause the weight and its associated valve needle to lift and tilt, thus opening the valve port to the atmosphere. The plate 21 is carried in a trough in the base plate 16, this trough being formed by upwardly projecting flanges 25 which, for sake of clarity have been omitted from Figure 1 and Figure 5 of the drawings. The side edges 26 of the slider plate are thus guided by these flanges 25 and in order to retain the plate against upward movement four inwardly projecting lugs 27 extend inwardly over the side edges 26. In order to allow the plate to be removed side edges 26 are notched at 28 and cut away so that removal of the plate can be effected by sliding it to the right, as shown in the drawings, and lifting it off upwardly when the lugs 27 are aligned with the notches 28 and the cut aways 29. As shown in Figures 1 and 3 of the drawings movement of the plate to the right is prevented by a manual operation lever 30 the operation of which will be described hereinafter but it will be observed that the lever can be moved to a position in which it is inoperative on the plate 21.

In order to control the plate 21 an angularly movable element in the form of an operation lever or knob is provided which is rotatably mounted on a spindle 53 provided on the base plate 16. The lever 30 has a cam surface 54 which can engage a downtumed lug 55 on the end of the slider plate 21. In order to maintain the downturned lug 55 against the cam surface 54 a compression spring 35 is provided one end of which is located on a spigot 36 provided in an opening 37 which is most clearly shown in Figure 3. The other end of the spring is located in a blind groove 38 formed in the base plate 16 which also carries a boss adapted to receive a securing pin 39, the boss having an engagement rod 40 onto which the pin can latch by a quarter turn to provide a twist and lock fastener of the well-known Dzus fastener type.This pin is carried and retained in an opening 41 in a housing which is made from a plastics material and extends over the base plate 16 and the slider plate 21. The relief valve weights 10, 11 and 12 project through an opening 43 in the housing and part of the wall of the opening 43 is cut back and formed with ribs 44 to provide a steam or gas opening 45 in the end of the housing.

In order to reduce friction between the slider plate 21 and the base plate 16 the upper surface of the base plate is provided with bearing projections (not shown).

In the arrangement shown in the drawings an emergency relief valve 52 is also provided in the lid.

It will be appreciated that when the needle valve (not shown) is opened steam will escape through the valve port 9 and will either pass through the gas escape opening 45 so that it is directed away from the handle of the cooker or escapes round the valve itself and through the opening 42, that is, upwardly, so that the steam is dispersed to the maximum extent.

The lever is held in position on the spindle 53 by the end portion 56 of the housing which overlaps it. The cam surface 54 is carried on an enlarged portion of the lever part of which projects beyond the housing, as is most clearly shown in Figure 2 and this projecting portion carries indicea 57 and 58 to indicate an operative position in which the valve is open (57) and a closed position (58).

Thus with the parts in the position in which the valve is open, movement of the control selector lever 30 to the closed position causes the cam surface 54 to move against the lug 55 and force the plate 16 to the left against the action of the spring 35 thus moving the wedges 23 out of contact with the weight 10 allowing the valve to close as shown in Figure 1.

When the cooker is to be used therefore the lid is placed in position and the lever is then turned to the closed position (58) in which the cam surface 54 pushes the wedges 23 on the slider plate 21 away from the body member 6 on the relief valve, that is, the position shown in Figure 1. In this position the relief valve is therefore closed. When cooking has been completed and it is desired to relieve the pressure within the cooker it is merely necessary to move the operating lever to the operative position (57) in which the lever and the lug 55 of the slider plate 21 is now on a lower part of the cam surface 54 thus allowing the spring 35 to push the wedges 23 beneath one side of the weight 10. This causes the weight 10 to tilt and thus lift the valve needle (not shown) away from the seating and allow gas and steam to escape from the interior of the cooker.Part of the gas and steam is directed away from the handle and lever where the operator's hand would be located by the steam escape opening 45 and part escapes upwardly around the valve weights through the opening 43.

To re-use the cooker it is merely necessary to return the lever to the first position which will thus allow the valve to close once more.

In an alternative construction (not shown) a ratchet is provided on the lever to allow a number of open positions to provide a variable controlled opening of the valve to allow rapid or slow steam escape.

For normal use it is necessary to be able to dismantle the assembly for cleaning and in order to do this the weight 10 with its valve needle (not shown) is first removed from the valve seating 7. The housing 42 is now separated from the base plate by undoing the securing pin 39 and the removal of the housing enables the lever 30 to be lifted from the spindle 53. The slider plate 21 can now be moved to the right until the notches 28 and cut out 24 are aligned with the lugs 27 and it too can be removed. The wing nut 8 is then undone which allows the valve seating 7 to be removed, as is shown in Figure 5, which enables the base plate 16 to be taken from the lid, again in the manner indicated in Figure 5.

The various parts can now be cleaned as required and assembly can take place in the reverse order.

The invention can also be employed as a pressure cooker relief valve in which the operating member is controlled by the action of a timer in the manner set forth in the Applicants' co-pending British Patent Application No.

22613/77 filed 27 May 1977, Serial No.

1600032.

WHAT WE CLAIM IS: 1. A pressure cooker relief valve assembly comprising a relief valve having a valve member and a valve seating one of which acts against the other under the pressure of biasing means to close a valve port and which can be opened by a predetermined fluid pressure within the cooker, and a valve operating member, movement of which in a substantially linear direction and/or in a single plane actuates means for relieving the pressure of the biasing means, said means comprising a wedge which is moved

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (17)

1. **WARNING** start of CLMS field may overlap end of DESC **.

   which it is inoperative on the plate 21.

   In order to control the plate 21 an angularly movable element in the form of an operation lever or knob is provided which is rotatably mounted on a spindle 53 provided on the base plate 16. The lever 30 has a cam surface 54 which can engage a downtumed lug 55 on the end of the slider plate 21. In order to maintain the downturned lug 55 against the cam surface 54 a compression spring 35 is provided one end of which is located on a spigot 36 provided in an opening 37 which is most clearly shown in Figure 3. The other end of the spring is located in a blind groove 38 formed in the base plate 16 which also carries a boss adapted to receive a securing pin 39, the boss having an engagement rod 40 onto which the pin can latch by a quarter turn to provide a twist and lock fastener of the well-known Dzus fastener type.This pin is carried and retained in an opening 41 in a housing which is made from a plastics material and extends over the base plate 16 and the slider plate 21. The relief valve weights 10, 11 and 12 project through an opening 43 in the housing and part of the wall of the opening 43 is cut back and formed with ribs 44 to provide a steam or gas opening 45 in the end of the housing.

   In order to reduce friction between the slider plate 21 and the base plate 16 the upper surface of the base plate is provided with bearing projections (not shown).

   In the arrangement shown in the drawings an emergency relief valve 52 is also provided in the lid.

   It will be appreciated that when the needle valve (not shown) is opened steam will escape through the valve port 9 and will either pass through the gas escape opening 45 so that it is directed away from the handle of the cooker or escapes round the valve itself and through the opening 42, that is, upwardly, so that the steam is dispersed to the maximum extent.

   The lever is held in position on the spindle 53 by the end portion 56 of the housing which overlaps it. The cam surface 54 is carried on an enlarged portion of the lever part of which projects beyond the housing, as is most clearly shown in Figure 2 and this projecting portion carries indicea 57 and 58 to indicate an operative position in which the valve is open (57) and a closed position (58).

   Thus with the parts in the position in which the valve is open, movement of the control selector lever 30 to the closed position causes the cam surface 54 to move against the lug 55 and force the plate 16 to the left against the action of the spring 35 thus moving the wedges 23 out of contact with the weight 10 allowing the valve to close as shown in Figure 1.

   When the cooker is to be used therefore the lid is placed in position and the lever is then turned to the closed position (58) in which the cam surface 54 pushes the wedges 23 on the slider plate 21 away from the body member 6 on the relief valve, that is, the position shown in Figure 1. In this position the relief valve is therefore closed. When cooking has been completed and it is desired to relieve the pressure within the cooker it is merely necessary to move the operating lever to the operative position (57) in which the lever and the lug 55 of the slider plate 21 is now on a lower part of the cam surface 54 thus allowing the spring 35 to push the wedges 23 beneath one side of the weight 10. This causes the weight 10 to tilt and thus lift the valve needle (not shown) away from the seating and allow gas and steam to escape from the interior of the cooker.Part of the gas and steam is directed away from the handle and lever where the operator's hand would be located by the steam escape opening 45 and part escapes upwardly around the valve weights through the opening 43.

   To re-use the cooker it is merely necessary to return the lever to the first position which will thus allow the valve to close once more.

   In an alternative construction (not shown) a ratchet is provided on the lever to allow a number of open positions to provide a variable controlled opening of the valve to allow rapid or slow steam escape.

   For normal use it is necessary to be able to dismantle the assembly for cleaning and in order to do this the weight 10 with its valve needle (not shown) is first removed from the valve seating 7. The housing 42 is now separated from the base plate by undoing the securing pin 39 and the removal of the housing enables the lever 30 to be lifted from the spindle 53. The slider plate 21 can now be moved to the right until the notches 28 and cut out 24 are aligned with the lugs 27 and it too can be removed. The wing nut 8 is then undone which allows the valve seating 7 to be removed, as is shown in Figure 5, which enables the base plate 16 to be taken from the lid, again in the manner indicated in Figure 5.

   The various parts can now be cleaned as required and assembly can take place in the reverse order.

   The invention can also be employed as a pressure cooker relief valve in which the operating member is controlled by the action of a timer in the manner set forth in the Applicants' co-pending British Patent Application No.

   22613/77 filed 27 May 1977, Serial No.

   1600032.

   WHAT WE CLAIM IS: 1. A pressure cooker relief valve assembly comprising a relief valve having a valve member and a valve seating one of which acts against the other under the pressure of biasing means to close a valve port and which can be opened by a predetermined fluid pressure within the cooker, and a valve operating member, movement of which in a substantially linear direction and/or in a single plane actuates means for relieving the pressure of the biasing means, said means comprising a wedge which is moved

   beneath the biasing means by movement of the operating member, and means for controlling the operating member from a point spaced away from the valve member.
2. 2. A pressure cooker relief valve assembly as claimed in claim 1, in which the wedge is carried on the operating member.
3. 3. A pressure cooker relief valve assembly as claimed in claim 2, in which the operating member is in the form of a flat plate on which two or more wedges are provided.
4. 4. A pressure cooker relief valve assembly as claimed in claims 1-3 in which the biasing means are provided by a weight.
5. 5. A pressure cooker relief valve assembly as claimed in claim 4, in which an additional removable weight is also provided to vary the biasing pressure.
6. 6. A pressure cooker relief valve assembly as claimed in claim 5 in which the construction of the weights is as set forth in the Applicants' UK Patent Specification No. 1 524 750.
7. 7. A pressure cooker relief valve assembly as claimed in claims 1-6 in which the relief valve is located in a housing having a gas escape opening through which gas escaping through the valve is directed.
8. 8. A pressure cooker relief valve assembly as claimed in claim 7 in which the gas escape opening has an outlet facing away from the means for controlling the operating member.
9. 9. A pressure cooker relief valve assembly as claimed in claims 7 or 8 in which the valve operating member and the means for controlling it are also located in the housing, an operative part of the control means extending out of the housing.
10. 10. A pressure cooker relief valve assembly as claimed in claims 1-9 in which the means for controlling movement of the valve operating member comprises an angularly movable element, which acts against the operating member to cause it to move linearly or in a single plane when rotated.
11. 11. A pressure cooker relief valve assembly as claimed in claim 10 in which the angularly movable element is in the form of a control knob or lever provided with a cam surface which bears against the operating member.
12. 12. A pressure cooker relief valve assembly as claimed in claim 11 in which the operating member is resiliently biased towards the cam surface.
13. 13. A pressure cooker relief valve assembly as claimed in claims 11-12 in which the control knob or lever has a ratchet to bias it towards two or more predetermined operative positions.
14. 14. A pressure cooker relief valve assembly as claimed in claims 11-13 when dependant on claim 9 in which part of the control knob or lever extends out of the housing.
15. 15. A pressure cooker relief valve assembly substantially as described herein with reference to and as shown in the accompanying drawings.
16. 16. A pressure cooker incorporating a relief valve assembly as claimed in any one of the preceding claims.
17. 17. A pressure cooker substantially as described with reference to and as shown in the accompanying drawings.