Gas spring accumulator
A gas spring accumulator comprising:—a housing ( 2, 3 ) provided with an inlet ( 20 ); and—a flexible diaphragm ( 4 ) dividing the interior of the housing into a working chamber ( 7 ) which is exposed to system pressure via the inlet, and a gas chamber ( 6 ); characterised in that the housing includes a diaphragm element ( 4 ) having one side exposed to system pressure via the inlet ( 20 ) and an opposite side exposed to a further chamber ( 13 ), a first non-return valve ( 17 ) arranged to admit atmospheric gas into the further chamber ( 13 ), and a second non-return valve ( 29 ) arranged to admit gas from the further chamber ( 13 ) into the gas chamber ( 6 ).
1. A gas spring accumulator comprising:
a housing ( 2 , 3 ) provided with an inlet ( 20 ); and
a flexible diaphragm ( 4 ) dividing the interior of the housing into a working chamber ( 7 ) which is exposed to system pressure via the inlet, and a gas chamber ( 6 );
wherein the diaphragm element ( 4 ) having one side exposed to system pressure via the inlet ( 20 ) and an opposite side exposed to a further chamber ( 13 ), a first non-return valve ( 17 ) arranged to admit atmospheric gas into the further chamber ( 13 ), and a second non-return valve ( 29 ) arranged to admit gas from the further chamber ( 13 ) into the gas chamber ( 6 ).
2. A gas spring accumulator according to claim 1 which includes an escape valve ( 34 ) which allows gas to leave the gas chamber ( 6 ) when the pressure increases therein.
3. A gas spring accumulator according to claim 1 in which one or both of the second non-return valve ( 29 ) and the escape valve ( 34 ) includes a valve element which is integrally formed with the diaphragm ( 4 ).
4. A gas spring accumulator according to claim 1 in which the working chamber ( 7 ) is provided with a fluid outlet ( 21 ) such that the fluid inlet and outlet ( 20 , 21 ) can be used to connect the working chamber into a flow line, and a non return valve ( 28 ) is disposed between the inlet and outlet ports ( 20 , 21 ).
5. A gas spring accumulator according to claim 1 in which the housing is provided with a port ( 23 ) which communicates with the gas chamber ( 6 ) and to which an external pressure vessel ( 24 ) is releasably attached, and the external pressure vessel is provided by a length of conduit ( 24 ).
6. A gas spring accumulator according to claim 5 in which the length of conduit ( 24 ) is flexible.
7. A gas spring accumulator according to claim 1 in which the diaphragm ( 4 ) carries a diaphragm support assembly ( 8 ).
8. A gas spring accumulator according to claim 7 in which the diaphragm support assembly comprises a pair of support elements ( 9 , 10 ) located on opposite sides of the diaphragm.
9. A gas spring accumulator according to claim 7 in which the diaphragm ( 4 ) is sealably sandwiched between the support elements ( 9 , 10 ) which are held together by a fixing element ( 11 ) passing through the diaphragm.
10. A gas spring accumulator according to claim 7 in which the working chamber ( 7 ) contains a first spring ( 14 ) which acts against the diaphragm support assembly ( 8 ).
11. A gas spring accumulator according to claim 10 in which the gas chamber ( 6 ) contains a second spring ( 36 ) which acts against the diaphragm support assembly ( 8 ) in opposition to the first spring ( 14 ).
12. A gas spring accumulator according to claim 7 in which an indicator member ( 32 ), movable by the diaphragm support assembly ( 8 ), projects through the wall of the housing.
13. A gas spring accumulator according to claim 12 in which the indicator member ( 32 ) projects into a sight element ( 33 ) which is mounted on the outside of the housing.