System and method for power pump performance monitoring and analysis
A power pump performance analysis system and methods includes a signal processor connected to certain sensors for sensing pressures and stresses in the cylinder chambers and the inlet and discharge piping of a single or multicylinder pump. Pump speed and pump piston position may be determined by a crankshaft position sensor. Performance analyses for pump work performed, pump cylinder chamber stress, pump fluid end useful cycles to failure, and crosshead loading and shock analysis are provided for estimating pump component life and determining times for component replacement before failure.
1. A method for determining selected performance parameters of a reciprocating piston power pump, said pump comprising components including a housing providing at least one fluid chamber therein, a fluid inlet valve opening into said chamber, a fluid discharge valve for discharging fluid from said chamber, a rotatable crankshaft or eccentric, a reciprocating piston operably connected to said crankshaft and operable to displace fluid from said chamber, at least one pressure sensor in communication with said chamber for measuring pressure therein, at least one position sensor for sensing the position of said piston with respect to said chamber, and a signal processor operably connected to said sensors for receiving signals from said sensors, respectively, said method including:
determining at least one performance parameter selected from a group consisting of pump hydraulic power per revolution of said crankshaft, pump hydraulic work performed per revolution of said crankshaft, chamber dynamic work performed per revolution of said crankshaft, total pump hydraulic work per revolution of said crankshaft, total chamber dynamic work per revolution of said crankshaft, average mechanical shock imposed on said housing, a cumulative stress cycle factor per revolution of said crankshaft, stress imposed on said housing for each chamber per revolution of said crankshaft, pump operating cycles in revolutions of said crankshaft to failure of at least one of said housing, said piston and said crankshaft, a stress factor to determine the number of equivalent stress cycles imposed on said housing per revolution of said crankshaft, housing life in months for each chamber per revolution of said crankshaft, crosshead load in a vertical direction, crosshead guide shock load and upper crosshead guide maximum shock load per revolution of said crankshaft; and
replacing one or more pump components prior to failure based on determining said at least one of said parameters.
2. The method set forth in claim 1 wherein:
said pump hydraulic power per revolution is determined by comparing average fluid discharge pressure, average fluid inlet pressure and average fluid flow rate with respect to said chamber.
3. The method set forth in claim 1 wherein:
said pump hydraulic work performed per revolution of said crankshaft is determined by dividing pump speed in revolutions per minute into pump hydraulic power per revolution.
4. The method set forth in claim 1 wherein:
said chamber dynamic work is determined by comparing a stress cycle factor with chamber maximum pressure divided by average fluid discharge pressure from said chamber multiplied by hydraulic work performed per revolution.
5. The method set forth in claim 1 wherein:
said average mechanical shock is determined by the summation of forces exerted on a crosshead guide provided in said housing.
6. The method set forth in claim 1 wherein:
the step of determining chamber cumulative stress cycle factor is carried out by summing the incremental pressure cycles compared with an incremental pressure differential during a fluid discharge stroke of said pump divided by the peak chamber pressure during said discharge stroke.
7. The method set forth in claim 1 wherein:
the step of determining the stress imposed on said housing for each chamber is carried out by comparing a stress concentration factor for intersecting bores of said chamber with an assumed minimum wall thickness of said chamber with a maximum chamber pressure and with the diameter of said piston.
8. The method set forth in claim 1 wherein:
the step of determining the number of pump operating cycles to failure from cyclic stress is determined by comparing a sample fatigue limit coefficient with a sample fatigue limit exponent with chamber differential stress cycle with pump cycles to failure for a chamber differential stress cycle greater than the lower fatigue limit of the material from which said housing is constructed.