OUTLET VALVES FOR FLUID TRANSPORT CONTAINERS

Abstract: An outlet valve (1) for a fluid transport container is adapted for connection to a fluid delivery conduit (3) via a releasable coupling means (7), the valve being openable to permit discharge of fluid from the container into the delivery conduit (3). Means (11) cooperating with the coupling means (7) are provided to prevent the valve (1) from opening when it is not connected to a conduit via the coupling means (7), such means (11) advantageously being in the form of a pneumatic switch arranged in a pneumatic supply line (12) for the valve.

Description: This invention relates to outlet valves for fluid transport containers, such as containers carried by or forming part of road and rail tankers. Fluid transport containers are typically provided with one or more outlet valves adapted to be releasably coupled to a delivery conduit such as a flexible hose or loading arm leading to suitable storage means when it is desired to discharge some or all of the fluid from the container. Such valves are openable either manually or by remote control by an operator via a suitable actuating means to permit release of fluid therethrough, and are closed when a desired amount of fluid has been delivered and when the container is in transit. An example of such a valve in the so-called A.P.I. valve commonly found on road tankers which includes a standard male coupling means adapted to be lockingly interengaged with complementary female coupling means connected to delivery hoses for supply e.g. of petrol or diesel to garage storage tanks. With such containers it is clearly important to avoid the escape of fluid to the outside which in the case of toxic of inflammable fluids may be a serious safety hazard and in this respect experience shows that inadvertent release of fluid via the outlet valve of the container can be a problem. Viewed from one aspect the invention provides an outlet valve for a fluid transport container, such valve being connectable to a fluid delivery conduit via a releasable coupling means and being openable to allow discharge of fluid from said container into the delivery conduit, characterised in that means associated with the coupling means are provided to prevent the valve from opening when it is not connected to a delivery conduit via such coupling means. In accordance with the invention the problem of inadvertent release of fluid via the outlet valve is avoided since such valve can only be opened when duly connected to a delivery conduit via the coupling means. The increase in safety thus provided is of particular significance e.g. in the case of a tank divided into a number of different containers or compartments, each of which has an outlet valve operated by remote control. In such a case it will be appreciated that there is potentially a greater risk that an operator may inadvertantly try to open one of the outlet valves which is not connected to a delivery conduit. The means for preventing the valve from opening may take any convenient form. Thus, a suitable sensing means associated with the coupling means may be e.g. electrically, hydraulically or mechanically coupled to a closure member of the valve to maintain such member in its closed condition at all times when the valve is not connected to a delivery conduit. Such closure member may also serve as the main closure member of the valve which is normally operable to open and close the valve as desired when connected to a delivery conduit, or alternatively may comprise an additional closure member arranged either upstream of or downstream from a main valve closure member. In a preferred embodiment of outlet valve which may include only a single closure member, the valve is pneumatically operable and includes a closure member which is movable into its open condition in response to pneumatic pressure applied from a supply line connected to a gas pressure source e.g. via a remote control unit. In such an embodiment, the means for preventing the valve from opening conveniently comprises a pneumatic switch arranged in the supply line and adapted to isolate the valve from the pressure source when the valve is not connected to a delivery conduit, regardless of the condition of the remote control unit. In a preferred such arrangement, the switch comprises a housing defining a bore having radially directed inlet and outlet ducts for connection in the pneumatic supply line, and a plunger arranged for axial movement in the bore between an open condition wherein the inlet and outlet ducts communicate with one another and a closed condition wherein gas flow between the ducts is prevented, said housing being mounted to or adjacent the coupling means and co-operating therewith so that the plunger is only moved to its open condition when the valve is connected to a conduit. Conveniently the plunger may be spring biased into its closed condition. In a preferred embodiment, the coupling means comprises complementary male and female parts adapted to be lockingly interengaged, one such part being connected to or forming part of the outlet valve of a container and the other part being connected to a delivery conduit such as a hose. In such an arrangement, the housing of the pneumatic switch may conveniently be mounted to or adjacent the part of the coupling means connected to or forming part of the valve, and an operating member for the plunger being arranged to co-operate with the other said part in such a way that when the parts are interconnected the plunger is moved to its open condition, against the spring biasing. Such an arrangement combines reliable operation with structural simplicity and, moreover, the pneumatic switch can be incorporated in existing valves and coupling means without the need for substantial modification thereof. The invention extends to a fluid transport con­ tainer, such as a container carried by or forming part of a road or rail tanker, incorporating one or more outlet valves as discussed above. A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, wherein: Fig. 1 is a schematic side elevation (partly in section) illustrating a valve in accordance with the invention coupled to a delivery hose; Fig. 2 is a schematic view illustrating the pneumatic switching valve in its closed condition. Referring to the drawings, an outlet valve 1 for a transport container in the form of an A.P.I. valve of a sort generally well known in the art includes a closure member 2 movable between an open condition wherein fluid may be released from the container into a delivery hose 3 and a closed condition (shown in broken lines in Fig. 1) wherein a discharge of fluid is prevented. The closure member is pneumatically operable by means of a piston 4 coupled to the closure member and displaceable in a chamber 5 in response to pneumatic pressure introduced into one side of the chamber via a duct 6. Thus, application of pneumatic pressure through duct 6 into the left-hand side of the chamber 5 causes movement of the closure member 2 rightwardly into its open condition. A biasing spring (not shown) is provided to return the closure member 2 to its closed condition when no pneumatic pressure is applied via the duct 6. As shown in Fig. 1, coupling means 7 are provided for releasably connecting the valve 1 to the delivery hose 3, the coupling means 7 including a male part 8, which in the illustrated embodiment forms part of the valve housing, and a complementary female part 9 connected to the hose 3. Locking members 10 are adapted releasably to interconnect the male and female parts, as is known in the art. In the illustrated valve, means are provided to prevent the valve from opening when not connected to a conduit via the coupling means 7. Such means comprises a pneumatic switch 11 arranged in the supply line 12 connecting the duct 6 to a pressure gas source via a remote control unit (not shown). The switch 11 comprises a housing 12 mounted to the valve housing and defining an axial bore 13 having radially arranged inlet and outlet ducts 14. Disposed in the bore 13 is a plunger 15 carrying an O-ring seal 16. A biasing spring 17 is adapted to urge the plunger 15 leftwardly as shown in the drawings, whilst an operating member 18 carried by the plunger is arranged to co-operate with a forward peripheral edge 19 of the female part 9 of the coupling means 7 when the parts of the coupling means are interconnected. Thus, as shown in Fig. 1 when the parts 8, 9 are interconnected, the operating member 18 is urged rightwardly against the biasing force of the spring 17 so that the plunger is moved into an open condition wherein the inlet and outlet ducts 14 communicate with one another. In this condition, pneumatic gas pressure can be applied to the chamber 5 via the duct 6 and the valve can be opened as desired consequent upon the line 12 being connected to the pressure gas source via the appropriate pneumatic switch of the remote control unit (not shown). However, when the female part 9 and thus the delivery hose 3 are detached from the valve 1, the biasing spring 17 urges the plunger leftwardly into the condition shown in Fig. 2, wherein the O-ring seal 16 is located axially between the inlet and outlet ducts 14 so that the duct 6 and housing 5 are isolated from the line 12. In this condition, it will be appreciated that the valve cannot be opened by inadvertent application of pneumatic pressure to the line 12 e.g. consequent upon the operator selecting the wrong pneumatic switch in the remote control unit. As shown in Fig. 1, the pneumatic switch 11 is connected to the duct 6 via a T-junction 20, the other arm of the T in a preferred embodiment being connected to an indicating means at the remote control unit adapted to provide a visual indication consequent upon application of pneumatic pressure. This provides the operator with confirmation that the valve has been duly opened, and the absence of a visual indication will alert the operator to the fact that no gas pressure has been applied to the duct 6 and therefore to the possibility of the wrong switch having been selected on the remote control unit. It is to be clearly understood that there are no particular features of the foregoing specification, or of any claims appended hereto, which are at present regarded as being essential to the performance of the present invention, and that any one or more of such features or combinations thereof may therefore be included in, added to, omitted from or deleted from any of such claims if and when amended during the prosecution of this application or in the filing or prosecution of any divisional application based thereon.

Claims: 1. An outlet valve for a fluid transport container, such valve being connectable to a fluid delivery conduit via a releasable coupling means and being openable to allow discharge of fluid from said container into the delivery conduit, characterised in that means associated with the coupling means are provided to prevent the valve from opening when it is not connected to a delivery conduit via such coupling means. 2. An outlet valve as claimed in claim 1 comprising a closure member which is movable into an open condition in response to pneumatic pressure applied to the valve via a supply line, said means for preventing the valve from opening comprising a pneumatic switch connected to the supply line and adapted to isolate the valve from the pneumatic pressure source when the valve is not connected to a delivery conduit. 3. An outlet valve as claimed in claim 2 wherein the switch comprises a housing defining a bore having radially directed inlet and outlet ducts for connection to the pneumatic supply line, and a plunger arranged for axial movement in the bore between an open condition wherein the inlet and outlet ducts communicate with one another and a closed condition wherein gas flow between the ducts is prevented, said housing being mounted to or adjacent the coupling means and co-operating therewith so that the plunger is only moved to its open condition when the valve is connected to a conduit. 4. An outlet valve as claimed in claim 3 wherein the plunger is spring biased into its closed condition. 5. An outlet valve as claimed in claims 3 and 4 wherein the coupling means comprises complementary male and female parts adapted to be lockingly interengaged, one such part being connected to or forming part of the outlet valve and the other part being connected to a delivery conduit, said pneumatic switch housing being mounted to or adjacent the part of the coupling means connected to or forming part of the valve, and an operating member for the plunger being arranged to co-operate with the other said part in such a way that when the parts are interconnected the plunger is moved to its open condition, against the spring biasing. 6. A fluid transport container including one or more outlet valves as claimed in any preceding claim.

Inventors: JAMES, SIMON
Applicants: EMCO WHEATON U.K. LIMITED
Application year: 1986
Main classification: F16L37
IPC codes: F16L37