Patent ID: 9695815
Date: 2017-07-04
CPC Classifications: F04B

Claim:
1. A pump device, comprising: a pump main body including a discharge port, a suction port, a pump chamber that is communicable with each of the discharge port and the suction port, a movable member that alternately suctions gas into the pump chamber and discharges gas from the pump chamber, and a drive unit including a motor that drives the movable member and is capable of changing a flow rate of gas discharged from the discharge port according to a rotation speed; a temperature sensor that is attached to the pump main body and measures a temperature of gas discharged from the discharge port or a temperature of the pump main body, to thereby output a temperature signal relating to a temperature of the gas; and a controller including an input terminal into which an external signal for specifying a reference flow rate of the gas discharged from the discharge port is input, an arithmetic circuit that calculates, based on the temperature signal, an actual flow rate of the gas discharged from the discharge port, and an output terminal that outputs a correction signal for correcting a rotation speed of the motor such that the actual flow rate equals the reference flow rate; wherein the controller further includes a memory that stores a correction coefficient including a temperature characteristic of the pump main body, which are obtained in advance, the arithmetic circuit calculates an actual flow rate of the gas by multiplying the correction coefficient with a gas flow rate calculated based on the temperature signal, the correction coefficient is an approximation function of the temperature characteristic from a first temperature to a second temperature higher than the first temperature, and the approximation function is used to generate a correction signal for increasing the rotation speed of the motor between the first temperature and a third temperature higher than the first temperature and lower than the second temperature.