Apparatus And Method For Pumping A Cryogenic Fluid From A Storage Vessel And Diagnosing Cryogenic Pump Performance

A method of delivering a process fluid that is stored at a cryogenic temperature comprises:

• (a) storing said process fluid inside a cryogen space defined by a storage vessel;
• (b) pumping said process fluid from said cryogen space with a cryogenic pump;
• (c) heating said process fluid to shift said process fluid into a gaseous phase;
• (d) measuring process fluid pressure downstream from said cryogenic pump;
• (e) determining from said measured process fluid pressure when performance of said cryogenic pump has degraded;
• and
• (f) signaling to an operator of said cryogenic pump when its performance is degraded below a predetermined threshold volumetric efficiency.

A method of delivering a process fluid that is stored at a cryogenic temperature comprises:

• (a) storing said process fluid inside a cryogen space defined by a storage vessel;
• (b) pumping said process fluid from said cryogen space with a cryogenic pump;
• (c) heating said process fluid to shift said process fluid into a gaseous phase;
• (d) measuring process fluid pressure downstream from said cryogenic pump;
• (e) commanding said cryogenic pump to an active pumping state when measured process fluid pressure is less than or equal to a predetermined low pressure set point;
• (f) commanding said cryogenic pump to an idle state when measured process fluid pressure is greater than or equal to a predetermined high-pressure set point;
• (g) recording an initial measured process fluid pressure each time said cryogenic pump is commanded to said active pumping state;
• (h) recording a final measured process fluid pressure after said cryogenic pump completes a predetermined number of consecutive pump cycles;
• (i) calculating a change in process fluid pressure by subtracting said initial measured process fluid pressure from said final measured process fluid pressure;
• (j) adding one to an error count if said change in process fluid pressure is less than a threshold value;
• and
• (k) determining and signaling to an operator of said cryogenic pump that performance of said pump is degraded if said error count reaches a predetermined number Nd.

A method of delivering a process fluid that is stored at a cryogenic temperature comprises:

• (a) storing said process fluid inside a cryogen space defined by a storage vessel;
• (b) pumping said process fluid from said cryogen space with a cryogenic pump;
• (c) heating said process fluid to shift said process fluid into a gaseous phase;
• (d) measuring process fluid pressure downstream from said cryogenic pump;
• (e) commanding said cryogenic pump to an active pumping state when measured process fluid pressure is less than or equal to a predetermined low pressure set point;
• (f) commanding said cryogenic pump to an idle state when measured process fluid pressure is greater than or equal to a predetermined high-pressure set point;
• (g) detecting when said cryogenic pump is commanded to said active pumping state from said idle state, and keeping a number count of pump cycles performed by said cryogenic pump to raise process fluid pressure downstream from said cryogenic pump to said high pressure set point;
• (h) resetting said number count to zero when said cryogenic pump is commanded to said idle state,
• (i) adding one to an error count if said number count is greater than or equal to a threshold number;
• and
• (j) determining and signaling to an operator of said cryogenic pump that performance of said pump is degraded if said error count reaches a predetermined number Nd.