Pump for exerting pressure on fluid and fluid tank unit having the same

A pump for exerting pressure on fluid that has higher saturation pressure than atmospheric pressure at room temperature in a fluid reserving chamber in a fluid tank, the pump being located near the fluid tank, the pump comprising:

• a housing defining a pump chamber, a motor chamber and a communication passage between the pump chamber and the motor chamber;
• an introducing port located in the housing for introducing the fluid into the pump chamber;
• a pump mechanism located in the pump chamber for exerting pressure on the fluid, the pump mechanism generating heat;
• a motor mechanism located in the motor chamber for driving the pump mechanism, the motor mechanism generating heat;
• and
• a bleeding port located above the introducing port for returning the fluid from the motor chamber to the fluid reserving chamber, the fluid carrying the heat.

A fluid tank unit comprising:

• a fluid tank having a fluid reserving chamber for reserving fluid that has higher saturation pressure than atmospheric pressure at room temperature;
• and
• a pump for exerting pressure on the fluid attached to the fluid tank, the pump comprising:
• a housing defining a pump chamber, a motor chamber and a communication passage between the pump chamber and the motor chamber, the housing including:
• at least one introducing port for introducing the fluid from the fluid reserving chamber into the housing;
• and
• a bleeding port located above the introducing port for returning the fluid from the housing to the fluid reserving chamber;
• and
• a heat generating mechanism located in the housing, wherein the fluid circulates into the housing through the introducing port and out of the housing through the bleeding port for substantially reducing the temperature in the housing.