GB2081846A

GB2081846A - Valve

Info

Publication number: GB2081846A
Application number: GB8121055A
Authority: GB
Original assignee: Gustav F Gerdts KG
Current assignee: Gustav F Gerdts KG
Priority date: 1980-08-14
Filing date: 1981-07-08
Publication date: 1982-02-24
Also published as: GB2081846B; FR2490773A1; ES504019A0; ES8205990A1; DE3030746A1; DE3030746C2

Abstract

A valve has a valve spindle (4) which on the inside of the valve casing (2) carries a closure member (3) and on the outside of the casing (2) is surrounded by a spring (6). One end of the spring (6) loads a packing (12) for the valve spindle (4) against the internal pressure of the casing (2) and a bearing member (7) is provided on the valve casing (2) which carries an actuating device (8) for the valve. A support plate (14) with a central passage opening for the valve spindle (4) is arranged between the spring (6) and the packing (12) and the bearing member (7) has stroke limit stops for the support plate (14) in front of the front face of the plate (14) remote from the packing (12). <IMAGE>

Description

SPECIFICATION Check valve This invention relates to a check valve of the type having a valve spindle which on the inside of the valve casing carries a closure member and on the outside of the casing is surrounded by a spring one end of which loads a packing for the valve spindle against the internal pressure of the casing.

An important advantage of check valves with spring-loaded packings for the valve spindle is in the automatic resetting of the seal. In addition, constructional expenditure is limited, particularly if in the case of a lifting valve the valve spring for the closure member simultaneously loads the packing, so that only one spring is required for both.

Since the pressure acting on the packing is determined by the valve spring and since for the design thereof the permitted or acceptable force for the valve operation is decisive it may occur in certain circumstances, e.g. in the case of water shocks or in the case of pressure testing of the valve with a very high test pressure, that the packing is forced out of the stuffing box bearing bore counter to the action of the valve spring, so that a leak occurs at this point.

This also happens if the spring fractures.

The present invention aims to provide a check valve of the aforementioned type in which there is no leak to the packing even in the case of a spring fracture or high internal pressure loading.

According to the invention, there is provided a check valve having a valve casing and a valve spindle, which on the inside of the casing carries a closure member and on the outside of the casing is surrounded by a spring, one end of the spring loading a packing for the valve spindle against the internal pressure of the casing, and a bearing member being provided on the valve casing which carries an actuating device for the check valve, wherein a support plate with a central passage opening for the valve spindle is arranged between the spring and packing and wherein the bearing member has stroke limit stops for the support plate in front of the front face of the plate remote from the packing. By means of the support plate, the bearing member prevents the forcing out of the packing from its bearing bore, so that leaks on the packing are prevented.

Preferably, the support plate comprises a round disc. This offers the advantage that it is possible to use commercially available, inexpensive parts as the support plate, e.g. a cup spring. Furthermore, unlike in the case of a strip-like support plate, there is no need for protection against torsion to ensure that the support plate is always ready to exercise a supporting function, even in the case of a bow-shaped bearing member.

According to a preferred embodiment of the invention, a pressure bush is provided between the support plate and packing, said pressure bush having a spigot engaging into the passage opening of the support plate, whilst between the latter and the stroke limit stops there is an axial clearance at least equal to the height of the spigot in the fitted condition. The pressure bush is also responsible for centering the circular support plate, whilst the support plate can still be laterally inserted without difficulty in its fitting position.

The invention will now be further described, by way of example, with reference to the drawings, in which: Figure lisa longitudinal section through one embodiment of a valve according to the invention; Figure 2 is a plan view of the valve shown in Figure 1; and Figure 3 is a side view of the valve shown in Figure 1.

Referring to the drawings, the valve comprises a closure member 3 which cooperates with a valve seat 1 and a valve casing 2. A valve spindle 4 projects through a cover 5 and out of the valve casing 1 and on the outside is surrounded by a valve spring 6. A U-shaped member 7 is integrally connected with the cover 5 by its two ends and serves as a bearing member for the valve actuating device. This is in fact a rocking lever 8 with a forked end which, by means of a driving pin 9 and a driving cap 10 exerts a stroke-adjusting action on the valve spring 6 and valve spindle 4. By mean of a guide pin 11 which can be laterally inserted into the member 7, if necessary, the rocking lever 8 and with it the closure member 3 can be locked in the closed or open position.

The valve spindle 4 is surrounded by a multilayer packing 12 in the cover 5. The valve spring 6 has a compressing action on the packing 12 via a pressure bush 13 and a support plate 14 comprising a cup spring and having a central passage opening for the valve spindle 4.

During assembly, the packing 12 is initially placed in the over 5 and is pressed forward to the extent which is necessary. The pressure bush 13 is then inserted. A vertical spacing corresponding at least to the total height of the support plate 14 is provided between the front face of the pressure bush 13 and stroke limit stops 15 provided internally on the member 7 in front of the end face of the support plate 14 remote from the bush 13. As a result, the plate 14 is introduced from the side between the stroke limit stops 15 and the pressure bush 13 and can be fitted on to a spigot 16 on the bush 13. The valve spring 6 with the fitted driving cap 10 is then inserted in the member 7. It is then merely necessary to fit the valve spindle 4 and rocking lever 8.

If such high pressures occur in the valve casing 2 that the packing 12 is forced upwards counter to the action of the valve spring 6 or the latter fractures, the support plate 14 engages with the stroke limit stops 15 preventing the bush 13 from being completely and the packing 12 from being partly forced out of the cover 5 so that a leak could form.

1. A check valve having a valve casing and a valve spindle, which on the inside of the casing carries a closure member and on the outside of the casing is surrounded by a spring, one end of the spring loading a packing for the valve spindle against the internal pressure of the casing, and a

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Check valve This invention relates to a check valve of the type having a valve spindle which on the inside of the valve casing carries a closure member and on the outside of the casing is surrounded by a spring one end of which loads a packing for the valve spindle against the internal pressure of the casing. An important advantage of check valves with spring-loaded packings for the valve spindle is in the automatic resetting of the seal. In addition, constructional expenditure is limited, particularly if in the case of a lifting valve the valve spring for the closure member simultaneously loads the packing, so that only one spring is required for both. Since the pressure acting on the packing is determined by the valve spring and since for the design thereof the permitted or acceptable force for the valve operation is decisive it may occur in certain circumstances, e.g. in the case of water shocks or in the case of pressure testing of the valve with a very high test pressure, that the packing is forced out of the stuffing box bearing bore counter to the action of the valve spring, so that a leak occurs at this point. This also happens if the spring fractures. The present invention aims to provide a check valve of the aforementioned type in which there is no leak to the packing even in the case of a spring fracture or high internal pressure loading. According to the invention, there is provided a check valve having a valve casing and a valve spindle, which on the inside of the casing carries a closure member and on the outside of the casing is surrounded by a spring, one end of the spring loading a packing for the valve spindle against the internal pressure of the casing, and a bearing member being provided on the valve casing which carries an actuating device for the check valve, wherein a support plate with a central passage opening for the valve spindle is arranged between the spring and packing and wherein the bearing member has stroke limit stops for the support plate in front of the front face of the plate remote from the packing. By means of the support plate, the bearing member prevents the forcing out of the packing from its bearing bore, so that leaks on the packing are prevented. Preferably, the support plate comprises a round disc. This offers the advantage that it is possible to use commercially available, inexpensive parts as the support plate, e.g. a cup spring. Furthermore, unlike in the case of a strip-like support plate, there is no need for protection against torsion to ensure that the support plate is always ready to exercise a supporting function, even in the case of a bow-shaped bearing member. According to a preferred embodiment of the invention, a pressure bush is provided between the support plate and packing, said pressure bush having a spigot engaging into the passage opening of the support plate, whilst between the latter and the stroke limit stops there is an axial clearance at least equal to the height of the spigot in the fitted condition. The pressure bush is also responsible for centering the circular support plate, whilst the support plate can still be laterally inserted without difficulty in its fitting position. The invention will now be further described, by way of example, with reference to the drawings, in which: Figure lisa longitudinal section through one embodiment of a valve according to the invention; Figure 2 is a plan view of the valve shown in Figure 1; and Figure 3 is a side view of the valve shown in Figure 1. Referring to the drawings, the valve comprises a closure member 3 which cooperates with a valve seat 1 and a valve casing 2. A valve spindle 4 projects through a cover 5 and out of the valve casing 1 and on the outside is surrounded by a valve spring 6. A U-shaped member 7 is integrally connected with the cover 5 by its two ends and serves as a bearing member for the valve actuating device. This is in fact a rocking lever 8 with a forked end which, by means of a driving pin 9 and a driving cap 10 exerts a stroke-adjusting action on the valve spring 6 and valve spindle 4. By mean of a guide pin 11 which can be laterally inserted into the member 7, if necessary, the rocking lever 8 and with it the closure member 3 can be locked in the closed or open position. The valve spindle 4 is surrounded by a multilayer packing 12 in the cover 5. The valve spring 6 has a compressing action on the packing 12 via a pressure bush 13 and a support plate 14 comprising a cup spring and having a central passage opening for the valve spindle 4. During assembly, the packing 12 is initially placed in the over 5 and is pressed forward to the extent which is necessary. The pressure bush 13 is then inserted. A vertical spacing corresponding at least to the total height of the support plate 14 is provided between the front face of the pressure bush 13 and stroke limit stops 15 provided internally on the member 7 in front of the end face of the support plate 14 remote from the bush 13. As a result, the plate 14 is introduced from the side between the stroke limit stops 15 and the pressure bush 13 and can be fitted on to a spigot 16 on the bush 13. The valve spring 6 with the fitted driving cap 10 is then inserted in the member 7. It is then merely necessary to fit the valve spindle 4 and rocking lever 8. If such high pressures occur in the valve casing 2 that the packing 12 is forced upwards counter to the action of the valve spring 6 or the latter fractures, the support plate 14 engages with the stroke limit stops 15 preventing the bush 13 from being completely and the packing 12 from being partly forced out of the cover 5 so that a leak could form. CLAIMS

1. A check valve having a valve casing and a valve spindle, which on the inside of the casing carries a closure member and on the outside of the casing is surrounded by a spring, one end of the spring loading a packing for the valve spindle against the internal pressure of the casing, and a bearing member being provided on the valve casing which carries an actuating device for the check valve, wherein a support plate with a central passage opening for the valve spindle is arranged between the spring and packing and wherein the bearing member has stroke limit stops for the support plate in front of the front face of the plate remote from the packing.

2. A check valve according to claim 1, wherein the support plate comprises a round disc.

3. A check valve according to claim 1 or claim 2, wherein a pressure bush is provided between the support plate and packing, said pressure bush having a spigot engaging into the passage opening of the support plate, whilst between the latter and the stroke limit stops there is an axial clearance at least equal to the height of the spigot in the fitted condition.