GB2450153A - Heat sensitive valve - Google Patents

Abstract

A heat-sensitive mechanical connection for a valve has a first connecting portion 10 for connection to actuating means (14, Fig. 11) and a second connecting portion 12 for connection to the spindle (16, Fig. 11) of a valve closure member (60, Fig. 11) of a shut-off valve S. The valve closure member is spring-biased towards a closed position. The first and second portions 10, 12 are releasably interengagable by means of projections 42, 44 and complementary recesses 40, 46 and are held in engagement by means of a heat-sensitive link 50 which extends between the first and second portions. Above a predetermined temperature, the heat-sensitive link 50 melts, allowing the first and second portions to disengage thereby allowing the valve closure member to shut by virtue of its spring biasing.

Description

1 2450153

DESCRI PTION

MECHANICAL CONNECTION AND VALVE COMPRISING THE

SAME

The present invention relates to mechanical connections and to valves comprising such connections, and in particular to such connections and valves which are heat-sensitive.

When fluids are transported in bulk in a tank container, they are discharged through a discharge valve which is commonly, but not always, positioned at a lowermost portion of the tank container. During discharge of fluid, the valve is mechanically held open against the force of a restoring spring which urges the valve towards its closed position.

However, it is a regulatory requirement that the discharge valve should close automatically in the event of a tire or other unplanned rise in temperature in the vicinity of the discharge valve.

In accordance with a first aspect of the present invention, a mechanical connection comprises a first connecting portion having connecting means for connection to actuating means and a second connecting portion having connecting means for connection to an article to be displaced, the connection further comprising interengaging means on the first and second portions and securing means for retaining the interengaging portions of the first and second portions in engagement with one another, the securing means comprising an element of reduced melting point extending between the first and second portions and which, when melted, disables the securing means and permits the interengaging means on the first and second portions to disengage.

Preferably, the interengaging means comprises a projection on one of the first and second connecting portions which is receivable in a recess in the other of the first and second connecting portions. More preferably, each of the first and second connecting portions comprises a projection and a recess, the projection of each connecting portion being receivable in a recess of the other connecting portion.

Preferably, the or each projection and recess are complementarfly shaped.

The interengaging means may comprise a hook portion on one of the first and second portions.

Preferably, each of the first and second portions comprises mounting means for connection of the element of reduced melting point.

The mounting means of at least one the first and second portions may conveniently comprise a pin.

The mounting means may further comprise a projecting portion to which the pin is secured.

In one embodiment, the mounting means comprises two projecting portions between which the pin extends.

In another embodiment, the mounting means comprises a single projecting portion from which the pin extends.

Preferably, the element of reduced melting point comprises a fusible link.

In one embodiment, the fusible link comprises first and second overlapping plate members joined by a layer of fusible material, each of the plate members of the fusible link being connected to the mounting means of a respective one of the first and second portions.

At least one of the first and second portions may be provided with a socket for receipt of a portion of the other of first and second portions.

The socket may be defined between two planar portions.

In one embodiment, the connecting means of one of the first and second portions is adapted to be connected to a valve spindle.

In accordance with a second aspect of the present invention, there is provided a valve comprising or fitted with a mechanical connection in accordance with the present invention.

Preferably, the valve comprises a valve closure member which is biased towards a preferred position (e.g. a closed position), whereby melting of the element of reduced melting point results in displacement of the valve closure member towards the preferred position.

By way of example only, specific embodiments of the present invention will now be described with reference to the accompanying drawings, in which:-Fig. I is a perspective view of a first embodiment of a mechanical connection in accordance with the present invention, shown in the intact condition; Fig. 2 is a side view of the connection of Fig. 1; Fig. 3 is a plan view of the connection of Fig. 1; Fig. 4 is an end view of the connection of Fig. 1; Fig. 5 is a longitudinal cross-section of the connection of Fig I; Fig. 6 is a perspective view of the connection of Fig. 1, shown in an actuated condition; Fig. 7 is a side view of the connection as shown in Fig. 6; Fig. 8 is a longitudinal cross-section of the connection as shown in Fig. 6; Figs. 9 to 11 are a side view, a plan view and a longitudinal cross-section respectively of a discharge valve fitted with the connection of Fig. 1; Fig. 12 is a perspective view of a second embodiment of mechanical connection in accordance with the present invention; Fig. 13 is a side view of the mechanical connection of Fig. 12; Fig. 14 is a plan view of the mechanical connection of Fig. 12; Fig. 15 is an end view of the mechanical connection of Fig. 12; and Fig. 16 is a longitudinal cross-section through the mechanical connection of Fig. 12.

Referring firstly to Figs. I to 11, a first embodiment of mechanical connection comprises first and second releasably interengagable portions 10, 12 which, as shown in Figs. 9 to 11, are adapted to be secured respectively to a valve actuator in the form of an actuating rod 14 and to the valve spindle 16 of a shut-off valve S forming part of a discharge valve assembly.

The first portion 10 of the mechanical connection comprises an elongate planar lug 20 having an aperture 22 at its distal end for receipt of a pivotal connector, as will be explained. The end of the lug 20 opposite the connection aperture 24 is formed into a clevis portion having two upstanding parallel tugs 24a, 24b. The distal ends of the tugs are each provided with one of two aligned apertures 26 for receipt of a retaining pin 28, as wilt be explained. The opposite ends of the upstanding Jugs are formed into two parallel cheek portions 30 which, as will be explained, form a socket to receive a projecting part of the second portion 12 of the mechanical connection.

The second portion 12 of the mechanical connection comprises a reinforced, intemally-splined 32 annular head which, as will be explained, is adapted to be received on the splined projecting portion of a valve spindle 16 connected to a valve closure member. Two upstanding parallel securing tugs 34a, 34b project upwardly from the annular head 32 and, in use, each of the Jugs is designed to be located in a co-planar manner with a respective one of the two Jugs 24a, 24b of the first portion 10. The distal ends of the two lugs 34a, 34b of the second portion 12 are also each provided with one of two aligned apertures 36 for receipt of a second securing pin 38, as will be explained.

As best seen in Fig. 5, the inner parts of two interengagable portions 10, 12 are adapted to abut and engage releasably with each other, with part of the second portion 12 received in the socket formed between the cheeks 30 of the first portion. In particular, the innermost face of the first connecting portion 10 is provided with a recess 40 which is adapted to receive a complimentarily-shaped projecting nose 42 of the second portion 12. Similarly, the innermost portion of the first connecting portion 10 is provided with a hook portion 44 in the form of an outwardly directed lip at a position remote from the parallel Jugs 24a, 24b, the lip 44 being received in a recess 46 formed by an overhanging intumed Jug 48 on the adjacent part of the second portion 12.

As best seen in Fig. 5, the first and second portions 10, 12 can be interengaged with each other by locating the projecting nose 42 of the second portion 12 in the recess 40 of the first portion and by locating the lip 44 of the first portion 10 in the recess 46 of the second portion 12. The two portions 10, 12 can be secured in engagement with each other by means of a fusible link 50 which extends between the tugs 24a, 24b of the first portion 10 and the tugs 34a, 34b of the second portion 12 respectively. The fusible link 50 comprises two thin parallel plates 52a, 52b of metal which are soldered together with a layer 54 of fusible alloy that is designed to melt at a reduced temperature compared with the other components of the mechanical connection. The two plates 52a, 52b of the fusible link overlap but each plate 52a, 52b is secured to only one pair of upstanding Jugs 24a, 24b, 34a, 34b. One of the plates 52a is secured to the upstanding tugs 24a, 24b of the first portion by means of the pin 28 passing through an aperture in one end of the plate and through the aligned apertures 26 in the tugs, whereupon it is secured by means of a split pin 56. Similarly, the other plate 52b is secured to the tugs 34a, 34b of the second portion 12 by means of the second securing pin 38 passing through the aligned apertures 36 in the upstanding lugs of the second portion and through an aperture in one end of the second plate 52b, whereupon it is secured by means of a split pin 58.

In the normal, intact, condition the fusible link 50 is rigid and retains the first and second portions 10, 12 in engagement with each other, whereby rotation of one of the portions 10, 12 results in rotation of the other portion 10, 12. The interengagement of the first and second portion bears approximately 70% of the forces, with the remaining 30% being borne by the fusible link 50.

In the event of a fire or other situation resulting in an unacceptable increase in temperature, the layer 54 of solder of the fusible link 50 melts.

If appropriate forces are applied to the first and second portions 10, 12, this allows the first and second portions to disengage from one another, as illustrated in Figs. 6 to 8 whereby the nose portion 42 of the second portion 12 separates from the recess 40 in the first portion 10. The two portions 10, 12 of the mechanical connection are then no longer constrained to move with each other.

Figs. 9 to 11 illustrate a discharge valve assembly which is fitted with the mechanical connection of Fig. 1. Briefly, the valve assembly comprises a shut-off valve S located upstream of a ball valve B, the two being connected together by means of a 90 elbow E. The shut-off valve S is conventional in nature and comprises a valve closure member 60 which is urged into sealing engagement with a frusto-conical valve seat 62 by means of a strong spring 64 located upstream of the valve closure member. The valve closure 60 member may be lifted from the valve seat to an open position by means of a finger member 66 which is received in a recess 68 in the downstream face of the valve closure member. The finger is pivotally Connected to one end of a crank arm 70 which is mountecj on the valve spindle 16 on which the splined annular head 32 of the second portion 12 of the mechanical connection is mounted. The aperture of the first portion 10 of the connection receives a pivot pin 72 which is secured to one end of the actuating rod 74 of the shut-off valve S. The end of the actuating rod 74 remote from the shut-off valve is formed into an inclined handle portion 76.

The ball valve B IS conventional in nature and essentially comprises a rotatable closure member 78 engagable with an annular valve seat. The rotatable closure member 78 is mounted on an actuating spindle 80 which projects out of the valve housing and to which a handle 82 is connected.

In order to open the shut-off valve S the handle portion 76 is displaced towards the right as illustrated in Figs. 9 and 11 respectively.

This results in displacement of the finger member 66 upwardly as shown in the drawings, resulting in displacement of the valve closure member away from the valve seat and opening of the shut-off valve S. In normal circumstances, the mechanical connection will assume the condition shown in Figs. I to 5, with the first and second portions 10, 12 interengaged with each other. As explained previously, in this situation the interengagement of the first and second portions take up approximately 70% of the forces with the remaining forces passing through the fusible link 50.

In the event of a fire or other situation resulting in an unacceptable increase in temperature, the fusible layer 54 of the fusible link 50 melts as desc,j previously. In view of the fact that the second connecting portion 12 is connected to the valve spindle 16 of the shut- off valve S which is biased strongly towards the closed position of the valve closure member by means of the compression spring 64, melting of the fusible layer 54 of the fusible link results in disengagement of the first and second portions 10, 12 of the mechanical connection which thereby assumes the condition shown in Figs. 6 to 8. In this Condition, the first and second connecting portions 10, 12 can move independently of each other and thus in the event of melting of the fusible link 50 the valve closure member of the shut-off valve S will be moved to its closed position by virtue of the compression spring 64, irrespective of the position of the handle portion 76 or the rod 14, i.e. the position of the first connecting portion 10 to which the handle portion 74 is attached. The invention therefore permits a failsafe operation of the shut-off valve S. A second embodiment of the present invention is illustrated in figs. 12 to 16. The principle of operation of the second embodiment is similar to that of the first embodiment, but less material is required in its Construction.

The mechanical connection of figs. 12 to 16 comprises a first connecting portion 110 and a second connecting portion 112, corresponding to the connecting portions 10, 12 of the first embodiment.

The first connecting portion 10 comprises a connection tug 120 having an aperture 122 for receipt of a pivot pin, as for the first embodiment. A planar securing lug 124 projects from the body of the first connecting portion and is provided with an integraJ(yformed outwardly projecting pin 126 which in use passes through an aperture in one of the plates 1 52a of a fusible link 150 identical to the fusible link 50 of the first embodiment, to which it is secured by means of a split pin 156.

The opposite face of the securing lug 124 forms one wall of a slot 130 for receipt of a projecting portion 131 of the second connecting portion 112, the other side of the slot being defined by a planar cheek portion 133 extending parallel to the planar securing lug 124.

The second connecting portion 124 comprises a reinforced, annular, internally splined head 132 adapted to be connected to an IS externally splined valve spindle, as will be explained. A single securing lug 134 projects from the enlarged head 132 and provided with an integrally formed connecting pin 138 which is adapted to pass through the securing aperture in the other plate I 52b of the fusible link 150, to which it is Connected by a second split pin 158.

As best shown in figs. 12, 14 and 16, the first and second portions 110, 112 are in abutment with, and are interengaged with, to each other.

In particular, the first connecting portion 110 is provided with a recess 140 which receives a projecting nose 142 of the second portion. In addition, the first portion 110 is provided with a downwardly projecting lip 144 which is received within an upwardly directed recess 146 defined by an inwardly and upwardly turned lip 148 on the second connecting portion 112.

The second embodiment operates in a manner very similar to the first embodiment In particular, in the intact condition as illustrated in the figures, the fusible link 150 retains the first and second connecting portions 110, 112 in engagement with each other. As for the first embodiment, the interengagement of the first and second portions 110, 112 conducts approximately 70% of the forces with the remaining forces passing through the fusible link 150. In the event of a fire or other circumstance resulting in an unwanted increase in temperature, the fusible link 150 melts and allows the first and second connecting portions 110, 112 to become disengaged from one another.

The invention is not restricted to the details of the foregoing embodiments. For example, fusible links having a different construction from those described above may be used.

Claims (20)

1. A mechanical connection comprising a first connecting portion having connecting means for connection to actuating means and a second connecting portion having connecting means for connection to an article to be displaced, the connection further comprising interengaging means on the first and second portions and securing means for retaining the interengaging portions of the first and second portions in engagement with one another, the securing means comprising an element of reduced melting point extending between the first and second portions and which, when melted, disables the securing means and permits the interengaging means on the first and second portions to disengage.

2. A mechanical connection as claimed in claim 1, wherein the interengaging means comprises a projection on one of the first and second connecting portions which is receivable in a recess in the other of the first and second connecting portions.

3. A mechanical connection as claimed in claim 1 or claim 2, wherein each of the first and second connecting portions comprises a projection and a recess, the projection of each connecting portion being receivable in the recess of the other connecting portion.

4. A mechanical connection as claimed in any of the preceding claims, wherein the or each projection and recess are complementanly-shaped.

5. A mechanical connection as claimed in any of the preceding claims, wherein the interengaging means comprises a hook portion on one of the first and second portions.

6. A mechanical connection as claimed in any of the preceding claims, wherein each of the first and second portions comprises mounting means for connection of the element of reduced melting point.

7. A mechanical connection as claimed in claim 6, wherein the mounting means of at least one of the first and second portions comprises a pin.

8. A mechanical connection as claimed in claim 7, wherein the mounting means further comprises a projecting portion to which the pin is secured.

9. A mechanical connection as claimed in claim 8, wherein the mounting means comprises two projecting portions between which the pin extends.

10. A mechanical connection as claimed in claim 8, wherein the mounting means comprises a single projecting portion from which the pin extends.

11. A mechanical connection as claimed in any of claims 6 to 10, wherein the element of reduced melting point comprises a fusible link.

12. A mechanical connection as claimed in claim 11, wherein the fusible link comprises first and second overlapping plate members joined by a layer of fusible material, each of the plate members of the fusible link being connected to the mounting means of a respective one of the first and second portions.

13. A mechanical connection as claimed in any of the preceding claims, wherein at least one of the first and second portions is provided S with a socket for receipt of a portion of the other of the first and second portions.

14. A mechanical connection as claimed in claim 13, wherein the socket is defined between two planar portions.

15. A mechanical connection as claimed in any of the preceding claims, wherein the connecting means of one of the first and second portions is adapted to be Connected to a valve spindle.

16. A mechanical connection substantially as herein described with reference to, and as illustrated in Figs. I to 8 or Figs. 12 to 15 of the accompanying drawings.

17. A valve comprising a mechanical connection as claimed in any of the preceding claims.

18. A valve as claimed in claim 17, further comprising a valve closure member biased towards a preferred position, whereby melting of the element of reduced melting point results in displacement of the valve closure member towards the preferred position.

19. A valve as claimed in claim 18, wherein the preferred position is a closed position.

20. A valve substantially as herein described with reference to, and as illustrated in, the accompanying drawings.