Valve assembly for a differential pressure sensor with automatic zero point calibration and flushing
A valve assembly ( 1 ) included in a system for measuring differential pressures in a fluid system and where the valve assembly ( 1 ) includes a valve body ( 7 ) with an inlet ( 13 ) and an outlet ( 14 ) for connection to the fluid system, ducts ( 32, 33 ) for communication with a differential pressure sensor ( 12 ) for registration the differential pressure, a cavity ( 22 ) including a calibration cone ( 10 ) which is movable in the cavity ( 22 ) between a measuring position and a position for zero point calibration/flushing via the valve assembly ( 1 ). In instances when the measuring position of the device does not exists, the calibration cone ( 10 ) separates the differential pressure sensor ( 12 ) from the fluid system, i.e., in its initial position, and, at the same time, the valve assembly ( 1 ), in this position, is automatic flushed so as to get rid of any enclosed air in the valve assembly ( 1 ).
1. A device comprising part of a system for measuring differential pressures in a fluid system, the device comprising:
a valve assembly ( 1 ) including a valve body ( 7 ) with an inlet ( 13 ) and an outlet ( 14 ) for connection to the fluid system,
ducts ( 32 , 33 ) for facilitating communication with a differential pressure sensor ( 12 ) for measurement of the differential pressure,
a cavity ( 22 ) communicating with the ducts ( 32 , 33 ) and the cavity ( 22 ) including a calibration spool ( 10 ) which is axially moveable, along the cavity ( 22 ), between a measure position and an axially spaced initial position for zero point calibration and flushing the valve assembly ( 1 ), and the calibration spool ( 10 ) separating the differential pressure sensor ( 12 ) from the fluid system when the calibration spool ( 10 ) is in the initial position, and the calibration spool ( 10 ) including sealing elements ( 27 ), which prevent fluid communication between the ducts ( 32 , 33 ) and the first cavity ( 22 ) when the calibration spool ( 10 ) is in the initial position,
wherein a flushing function is obtained when the calibration spool ( 10 ) is spaced from the measuring position, the calibration spool ( 10 ) has a design that permits an open passage of flow between a high pressure side and a low pressure side, from the inlet ( 13 ), via a duct ( 21 ) between the inlet ( 13 ) and the cavity ( 22 ) in the valve body ( 7 ), to the cavity ( 22 ) in the valve body ( 7 ), through a cavity ( 26 ) in the calibration spool ( 10 ) and further to the cavity ( 22 ) in the valve body ( 7 ), thereafter to a duct ( 23 ) between the cavity ( 22 ) in the valve body ( 7 ) and the outlet ( 14 ) and thereafter to the outlet ( 14 ).
2. The device according to claim 1 , wherein the calibration spool ( 10 ), in its measuring position, provides communication between the fluid system and the differential pressure sensor ( 12 ), and, when the calibration spool ( 10 ) is in the measuring position, the sealing element ( 27 ) of the calibration spool ( 10 ) avoids blocking the ducts ( 32 , 33 ) to the differential pressure sensors ( 12 ) from the cavity ( 22 ) so as to facilitate communication with the differential pressure sensor ( 12 ).
3. The device according to claim 1 , wherein a return spring ( 35 ) is arranged to always return the calibration spool ( 10 ) to its initial position, in positions other than the measuring position.
4. The device according to claim 1 , wherein the valve assembly ( 1 ) includes an actuator ( 2 ) which is arranged to change the position of the calibration spool ( 10 ) in the cavity ( 22 ).
5. The device according to claim 4 , wherein the actuator ( 2 ) is remote controlled.
6. The device according to claim 2 , wherein a return spring ( 35 ) is arranged to always return the calibration spool ( 10 ) to its initial position, in positions other than the measuring position.
7. The device according to claim 2 , wherein the valve assembly ( 1 ) includes an actuator ( 2 ) which is arranged to change the position of the calibration spool ( 10 ) in the cavity ( 22 ).
8. The device according to claim 3 , wherein the valve assembly ( 1 ) includes an actuator ( 2 ) which is arranged to change the position of the calibration spool ( 10 ) in the cavity ( 22 ).
9. The device according to claim 6 , wherein the valve assembly ( 1 ) includes an actuator ( 2 ) which is arranged to change the position of the calibration spool ( 10 ) in the cavity ( 22 ).
10. The device according to claim 7 , wherein the actuator ( 2 ) is remote controlled.
11. The device according to claim 8 , wherein the actuator ( 2 ) is remote controlled.
12. The device according to claim 9 , wherein the actuator ( 2 ) is remote controlled.