Patent ID: 6742994
Filing Date: 2004-06-01
Classification: F04B

Abstract:
In a reciprocating pump wherein the inhaling and exhaling of a fluid are effected by making use of a reciprocating member and including malfunction-detecting means attached to the pump for the purpose of detecting abnormalities in the inhaling and exhaling of said fluid, the improvement wherein said malfunction-detecting means comprises a piezoelectric element for detecting a pressure fluctuation on a delivery side of the pump and wherein said reciprocating pump comprises a main body having a cylinder portion provided with an inhaling port and an exhaling port, a delivery passageway member communicated via a first pressure-adjusting valve with the exhaling port of the main body, a second pressure-adjusting valve disposed on a downstream side of the delivery passageway member, the reciprocating member reciprocatively fitted in the cylinder portion to thereby enable a fluid to be inhaled through said inhaling port and the fluid thus inhaled to be exhaled from said exhaling port to a pressure detecting chamber, and a solenoid for driving the reciprocating member, wherein the pressure adjustment value of the second pressure-adjusting valve is set higher than the pressure adjustment value of the first pressure-adjusting valve, and a pressure fluctuation of the fluid inside the pressure detecting chamber is directly transmitted to the piezoelectric element.