Method for detection of a fluid leak related to a piston machine

#The present application claims the benefit of priority to PCT/NO2008/000276 filed Jul. 25, 2008, which claims the benefit of Norwegian Application No. 20074261 filed Aug. 21, 2007, both of which are incorporated herein by reference in their entirety for all purposes.

#Not applicable.

#This invention concerns detection of a fluid leak in relation to a piston machine. More specifically, the method for detection of a fluid leak related to at least one piston machine (1) includes: attaching a pressure sensor to at least a pressure side of the at least one piston machine; measuring the pressure on the pressure side of the at least one piston machine; attaching a sensor to the at least one piston machine, said sensor rendering a signal for calculating the rotational speed of the at least one piston machine; calculating the speed of the at least one piston machine; calculating the sum of nominal flow rates from all piston machines; calculating a flow rate compensation factor; calculating a normalized pressure to be equal to the discharge pressure multiplied by the said flow rate compensation factor; and monitoring the normalized pressure to detect a leakage.

#In the following there is described a non-limiting example of use of the method illustrated in the accompanying drawings, in which:

#FIG. 1 schematically shows a pump with upstream and downstream pipe connections; and

#FIG. 2 shows an idealized graph illustrating the normalized pressure versus time.

#On the drawings the reference numeral 1 denotes a so-called triplex pump, below termed pump, provided with three individually acting pistons 2 extending through their respective cylinders 4. Only the first piston 2 and corresponding cylinder 4 are shown. The cylinders 4 communicate with an inlet manifold 6 and an upstream pipe 8 through their respective inlet valves 10, and an outlet manifold 12 and a downstream pipe 14 through their respective outlet valves 16.

#An inlet pressure sensor 18 is connected to the inlet manifold 6, communicating with a computer 20 via a cable 22, and an outlet pressure sensor 24 is connected to the outlet manifold 12, communicating with the computer 20 via a cable 26. A rotational angle transmitter 28 is arranged to measure the rotational angle of a crankshaft 30 of the pump 1, communicating with the computer 20 by means of a cable 32.

#A temperature sensor 34 and a density meter 36 are connected to the downstream pipe 14 and communicate with the computer 20 through cables 38 and 40 respectively.