Constant-temperature liquid supply system

A constant-temperature liquid supply system for supplying liquid from a liquid supply source to a processing machine after controlling the liquid to a constant temperature, comprising:

• a housing;
• an inlet disposed in the housing such that the liquid is allowed to flow from the liquid supply source into the housing;
• an outlet disposed in the housing such that the liquid is allowed flow out of the housing to the processing machine;
• a communication path that is enclosed in the housing and that allows communication between the inlet and the outlet;
• and
• a heating unit arranged in the communication path to heat the liquid to the constant temperature,
• wherein the heating unit includes:
• a heater casing having a first end wall and a second end wall,
• a first heater that is attached to the first end wall of the heater casing and that has at least one heater portion to heat the liquid, and
• a disk-shaped lid body that hermetically encloses a space within the heater casing and is detachably attached to the second end wall of the heater casing,
• wherein the lid body is detached and removed from the second end wall and a second heater that has at least one heater portion to heat the liquid is detachably attached to the second end wall of the heater casing when the first heater alone is insufficient to heat the liquid to the constant temperature, and
• the space within the heater casing accommodates the at least one heater portion of the first heater, and when the second heater is detachably attached to the second end wall of the heater casing, also allows accommodation of the at least one heater portion of the second heater.