| 摘要 |
PCT No. PCT/GB83/00047 Sec. 371 Date Oct. 13, 1983 Sec. 102(e) Date Oct. 13, 1983 PCT Filed Feb. 16, 1983 PCT Pub. No. WO83/02825 PCT Pub. Date Aug. 18, 1983.A meter prover comprises a cylinder (16) having a proving bore (22) and enlarged end chambers (20). A piston (12) is mounted within the cylinder for movement along the bore in sealed engagement therewith, the axial length of the piston exceeding that of the enlarged end chamber. When the piston is at rest in the end chamber, fluid can pass through a continuously open passage in the piston. This passage preferably takes the form of apertures (24) in an annular wall portion (36). When the piston is moved out of the end chamber, flow through the passage is no longer possible and the piston continues in synchronism with the fluid flow. At the end of the proving run, the progressive closing of the apertures provides a fluid damping effect to arrest the piston.
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