If you need to control temperature of fluid within a canal, you can use Eyvaz Canal Sensor. It has to be attached on manual sensor and then you can control temperature of the canal.
This sensor works based on physical rule of liquid expansion. Temperature sensor of this device is placed inside the tank and must be in touch with fluid constantly. When temperature goes up, mass of fluid increase and this variation is transferred to temperature sensor and mass of oil inside the device increase too. In effect of this, operating element pushes a force on seat and rod and gets back again and releases it. This operation repeats again and again and Debi of fluid stays under control in this way. Adjustable temperatures are ditched on the plate of device and it is usable with turning the switch.
Get assure that defined space of installation is enough and proper to attach operating element to valve. At the other hand, to install temperature sensor enough space is needed. This device is proper to adjust temperature of pipelines, heat exchangers, Coil containers, pools, tanks and so on. Body of temperature sensor must be inside environment of the fluid up to thread connection place. First weld a thread socket (1") to tank. Then wind the socket set screw or pod of the sensor and seal it. Then using switch on the device, adjust the set point on maximum degree. Insert temperature sensor using socket screw or pod and fasten it with its own nut. If fluid is acidic or corrosive proper material for pod must be used. While using pod it is recommended to fulfill space between temperature sensor and the pod with oil or other conductive fluid (Thermal). But remember to do not fulfill it completely; otherwise pod or sensor will be damaged.