Diaphragm pump and pressure regulating apparatus

Abstract

A diaphragm pump includes a fluid inlet, a fluid discharge port, and a fluid exhaust port that are open to outside of the diaphragm pump. The diaphragm pump further includes a pump chamber formed by a diaphragm, a suction passage that makes the pump chamber communicate with the fluid inlet; a suction valve that opens/closes the suction passage; a discharge passage that makes the pump chamber communicate with the fluid discharge port; a discharge valve that opens/closes the discharge passage; and an exhaust passage that makes the discharge passage communicate with the fluid exhaust port.

What is claimed is: 
     
         1 . A diaphragm pump comprising:
 a diaphragm including a cup-shaped pump portion;   a pump chamber including a wall including the pump portion;   a driver connected to a bottom of the pump portion and configured to convert a rotation into a reciprocating motion and increase/decrease a capacity of the pump chamber;   a fluid inlet, a fluid discharge port, and a fluid exhaust port that are open to outside of the diaphragm pump;   a suction passage configured to make the pump chamber communicate with the fluid inlet;   a suction valve configured to open/close the suction passage to make a fluid flow from the fluid inlet toward the pump chamber in a process in which the capacity of the pump chamber increases;   a discharge passage configured to make the pump chamber communicate with the fluid discharge port;   a discharge valve configured to open/close the discharge passage to make the fluid flow from the pump chamber toward the fluid discharge port in a process in which the capacity of the pump chamber decreases; and   an exhaust passage configured to make the discharge passage communicate with the fluid exhaust port.   
     
     
         2 . The pump according to  claim 1 , wherein the exhaust passage is always open. 
     
     
         3 . The pump according to  claim 1 , wherein the exhaust passage is connected to an area on a downstream side of the discharge valve in the discharge passage. 
     
     
         4 . The pump according to  claim 1 , wherein a width of the fluid exhaust port is smaller than a width of the fluid discharge port. 
     
     
         5 . A pressure regulating apparatus comprising:
 a diaphragm pump according to  claim 1 ;   a motor configured to apply a rotational force to the driver; and   a controller configured to control an operation of the motor,   wherein the controller is configured to control a rotational speed of the motor and regulate a pressure of the fluid discharged from the fluid discharge port.   
     
     
         6 . The apparatus according to  claim 5 , further comprising:
 a fluid passage configured to make the discharge passage communicate with a pressurization target object; and   an exhaust valve configured to selectively exhaust the fluid in the fluid passage.   
     
     
         7 . The apparatus according to  claim 6 , further comprising a pressure sensor configured to detect a pressure in the fluid passage,
 wherein the controller is configured to control the rotational speed based on the pressure detected by the pressure sensor.   
     
     
         8 . The apparatus according to  claim 5 , wherein the controller is configured to control the rotational speed and regulate the pressure not only when the pressure is increased, but also when the pressure is decreased. 
     
     
         9 . A pressure regulating apparatus comprising:
 a diaphragm including a cup-shaped pump portion;   a pump chamber including a wall including the pump portion;   a driver connected to a bottom of the pump portion and configured to convert a rotation into a reciprocating motion and increase/decrease a capacity of the pump chamber;   a motor configured to apply a rotational force to the driver;   a fluid inlet, a fluid discharge port, and a first exhaust port that are open to outside of the diaphragm pump;   a suction passage configured to make the pump chamber communicate with the fluid inlet;   a suction valve configured to open/close the suction passage to make a fluid flow from the fluid inlet toward the pump chamber in a process in which the capacity of the pump chamber increases;   a discharge passage configured to make the pump chamber communicate with the fluid discharge port;   a discharge valve configured to open/close the discharge passage to make the fluid flow from the pump chamber toward the fluid discharge port in a process in which the capacity of the pump chamber decreases;   a first exhaust passage configured to make the first exhaust port communicate with an area in the discharge passage between a fluid outlet of the discharge valve and the fluid discharge port;   a differential pressure regulating valve configured to close the first exhaust passage when a pressure on an upstream side from the fluid outlet of the discharge valve in the discharge passage is higher than a pressure in the first exhaust passage, and open the first exhaust passage when the pressure on the upstream side from the fluid outlet of the discharge valve in the discharge passage is not higher than the pressure in the first exhaust passage; and   a controller configured to control an operation of the motor,   wherein the controller is configured to control a rotational speed of the motor and regulate a pressure of the fluid discharged from the fluid discharge port.   
     
     
         10 . The apparatus according to  claim 9 , further comprising:
 a second exhaust port that is open to the outside of the diaphragm pump; and   a second exhaust passage configured to make the second exhaust port communicate with the area in the discharge passage between the fluid outlet of the discharge valve and the fluid discharge port.   
     
     
         11 . The apparatus according to  claim 10 , wherein the second exhaust passage is always open. 
     
     
         12 . The apparatus according to  claim 10 , wherein a width of the second exhaust port is smaller than a width of the fluid discharge port. 
     
     
         13 . The apparatus according to  claim 9 , further comprising:
 a third exhaust port that is open to the outside of the diaphragm pump; and   a third exhaust passage configured to make the third exhaust port communicate with an area on the upstream side from the fluid outlet of the discharge valve in the discharge passage.   
     
     
         14 . The apparatus according to  claim 9 , further comprising:
 a fluid passage configured to make the discharge passage communicate with a pressurization target object; and   a pressure sensor configured to detect a pressure in the fluid passage,   wherein the controller is configured to control the rotational speed based on the pressure detected by the pressure sensor.   
     
     
         15 . The apparatus according to  claim 9 , wherein the controller is configured to control the rotational speed and regulate the pressure not only when the pressure is increased, but also when the pressure is decreased.