Method and apparatus to test for valve leakage in a pump assembly
First Claim
1. A pump assembly having the capacity to self test for leakage, comprising:
- (a) a pumping chamber in which a fluid is pressurized during a pumping cycle;
(b) an inlet valve that periodically interrupts fluid flow into and out of the pumping chamber, with respect to a source of the fluid disposed upstream of the inlet valve;
(c) an outlet valve that periodically interrupts fluid flow into and out of the pumping chamber, with respect to a delivery passage through which a pressurized fluid flows when the pump assembly is operating to pump the fluid;
(d) a pressure sensor, disposed downstream of the outlet valve and operative to sense the pressure of the fluid and to produce a signal indicative of that pressure; and
(e) control means for controlling the pumping cycle, including self test means connected to receive the signal produced by the pressure sensor, for;
(i) filling the pumping chamber with fluid;
(ii) closing the inlet and outlet valves;
(iii) equalizing pressure in the pump assembly distal to the inlet valve;
(iv) opening the outlet valve and then determining a reference pulse as a function of the signal produced by the pressure sensor when the outlet valve is opened;
(v) closing the outlet valve and effecting at least a partial pumping cycle to pressurize fluid in the pumping chamber for a predetermined time interval, and thereafter terminating the pumping cycle;
(vi) opening the outlet valve after the pumping chamber has been pressurized; and
(vii) determining whether the pump assembly has leaked, as a function of the reference pulse and the signal produced by the pressure sensor after the outlet valve is opened in section (e)(vi).
2 Assignments
0 Petitions
Accused Products
Abstract
A method and apparatus for determining leakage, particularly of valves, in a pump assembly. A pump assembly (20) includes a primary valve (34) and a secondary valve (36), which may be selectively activated to control the source of fluid input to the pump assembly. The pump assembly also includes an inlet valve (42) and an outlet valve (50) disposed on each side of the pumping chamber (46). Downstream of the outlet valve is disposed a pressure sensor (54), which produces a signal indicative of the pressure of fluid within the pump assembly at that point. Leakage in the inlet or outlet valves is detected in the inlet or outlet valves by filling the pumping chamber with fluid, closing the inlet and outlet valves, and equalizing the pressure in the pump assembly distal to the inlet valve. After the pressure has been equalized, the outlet valve is opened and a reference pulse is determined as a function of the signal produced by the pressure sensor. The outlet valve is then closed and at least a partial pumping cycle is effected to pressurize fluid in the pumping chamber. The outlet valve is opened and a pressure pulse should propagate down the delivery passage from the pumping chamber. If the difference between the magnitude of the pressure pulse and that of the reference pulse is less than a predetermined value, either the inlet or outlet valve has leaked. The primary and secondary valves are checked for leakage in much the same manner.
59 Citations
39 Claims
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1. A pump assembly having the capacity to self test for leakage, comprising:
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(a) a pumping chamber in which a fluid is pressurized during a pumping cycle; (b) an inlet valve that periodically interrupts fluid flow into and out of the pumping chamber, with respect to a source of the fluid disposed upstream of the inlet valve; (c) an outlet valve that periodically interrupts fluid flow into and out of the pumping chamber, with respect to a delivery passage through which a pressurized fluid flows when the pump assembly is operating to pump the fluid; (d) a pressure sensor, disposed downstream of the outlet valve and operative to sense the pressure of the fluid and to produce a signal indicative of that pressure; and (e) control means for controlling the pumping cycle, including self test means connected to receive the signal produced by the pressure sensor, for; (i) filling the pumping chamber with fluid; (ii) closing the inlet and outlet valves; (iii) equalizing pressure in the pump assembly distal to the inlet valve; (iv) opening the outlet valve and then determining a reference pulse as a function of the signal produced by the pressure sensor when the outlet valve is opened; (v) closing the outlet valve and effecting at least a partial pumping cycle to pressurize fluid in the pumping chamber for a predetermined time interval, and thereafter terminating the pumping cycle; (vi) opening the outlet valve after the pumping chamber has been pressurized; and (vii) determining whether the pump assembly has leaked, as a function of the reference pulse and the signal produced by the pressure sensor after the outlet valve is opened in section (e)(vi). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. In a pump assembly including in inlet valve, an outlet valve, a chamber in which fluid is pressurized during a pump cycle, and a pressure sensor disposed downstream of the outlet valve, a method for testing the leak-proof integrity of the pump assembly, comprising the steps of:
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(a) filling the pumping chamber with fluid; (b) closing the inlet and outlet valves; (c) opening the outlet valve after equalizing pressure in the pump assembly distal to the inlet valve; (d) monitoring the fluid pressure downstream of the outlet valve, after it is opened; (e) determining a reference pressure as a function of said fluid pressure when the outlet valve is opened; (f) closing the outlet valve and effecting at least a partial pumping cycle to pressurize fluid in the pumping chamber for a predetermined time interval, then terminating the pumping cycle; (g) opening the outlet valve after the pumping chamber has been pressurized; and (h) determining whether the pump assembly has leaked, as a function of the reference pressure and said fluid pressure, after the outlet valve is opened in step (g). - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. In a pump assembly having a plurality of valves, including an inlet valve and an outlet valve, and the pumping chamber disposed between the inlet valve and the outlet valve, apparatus to test for leakage of the pump assembly, comprising:
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(a) pressure sensing means for producing a signal indicative of the pressure of fluid in a fluid passage downstream of the outlet valve; (b) reference pulse determining means, connected to receive the signal produced by the pressure sensing means, for determining a reference pulse as a function of the signal produced by the pressure sensing means immediately after the outlet valve is opened, said outlet valve being opened after the pressure of fluid in the pump assembly distal to the inlet valve has been equalized to that distal of the outlet valve; and (c) leak detection means, connected to receive the signal produced by the pressure sensing means, for detecting leakage from the pump assembly as a function of the reference pulse and the signal produced by the pressure sensing means immediately after the outlet valve is opened, said outlet valve being opened after fluid within the pumping chamber has been pressurized for a predetermined interval of time. - View Dependent Claims (34, 35, 36, 37, 38, 39)
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Specification