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.

1 .- 15 . (canceled) 
     
     
         16 . A control method of a diaphragm pump comprising:
 a diaphragm including a cup-shaped pump portion;   a pump chamber defined by 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,   the control method comprising:   increasing a rotational speed of a motor configured to apply a rotational force to the driver to increase a pressure of the fluid discharged from the fluid discharge port, and   decreasing the rotational speed of the motor to decrease the pressure of the fluid discharged from the fluid discharge port.   
     
     
         17 . The control method according to  claim 16 , wherein the exhaust passage is always open. 
     
     
         18 . The control method according to  claim 16 , wherein the exhaust passage is connected to an area on a downstream side of the discharge valve in the discharge passage. 
     
     
         19 . The control method according to  claim 16 , wherein a width of the fluid exhaust port is smaller than a width of the fluid discharge port. 
     
     
         20 . The control method according to  claim 16 , further comprising:
 selectively exhausting, with an exhaust valve, the fluid in a fluid passage configured to make the discharge passage communicate with a pressurization target object.   
     
     
         21 . The control method according to  claim 20 , further comprising:
 detecting a pressure in the fluid passage with a pressure sensor, and   controlling the rotational speed based on the pressure detected by the pressure sensor.   
     
     
         22 . A control method of a diaphragm pump comprising:
 a diaphragm including a cup-shaped pump portion;   a pump chamber defined by 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 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; and   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,   the control method comprising:   increasing a rotational speed of a motor configured to apply a rotational force to the driver to increase a pressure of the fluid discharged from the fluid discharge port, and   decreasing the rotational speed of the motor to decrease the pressure of the fluid discharged from the fluid discharge port.   
     
     
         23 . The control method according to  claim 22 , wherein the diaphragm pump further comprises:
 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.   
     
     
         24 . The control method according to  claim 23 , wherein the second exhaust passage is always open. 
     
     
         25 . The control method according to  claim 23 , wherein a width of the second exhaust port is smaller than a width of the fluid discharge port. 
     
     
         26 . The control method according to  claim 22 , wherein the diaphragm pump further comprises:
 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.   
     
     
         27 . The control method according to  claim 22 , further comprising:
 detecting, with a pressure sensor, a pressure in a fluid passage configured to make the discharge passage communicate with a pressurization target object; and   controlling the rotational speed based on the pressure detected by the pressure sensor.