Temperature Control Valves
Temperature control valves are valves which control fluid flow by varying the size of one or more flow passages. This enables the direct control of flow rate and the consequential control of system temperature.
3-way temperature control valves of the type supplied by Walton Engineering vary the size of two separate flow passages simultaneously – the pipe to the cooler and that to the bypass. In this way the flow is automatically proportioned between the cooler and bypass to enable the required temperature to be achieved and then maintained. The movement of a rotor within the valve causes the necessary flow distribution to achieve this.
The animation below shows a Walton temperature control valve working continuously to maintain a constant system temperature despite a varying load on the heat source.
Valve diverts all fluid through the bypass to enable the required temperature to be reached quickly.
Valve divides the fluid between the bypass and cooler to maintain the required temperature.
Valve sends all the fluid through the cooler to reduce the temperature.
Temperature control valves are typically used to control lubricating oil temperatures in diesel engines, turbines and compressors, and also engine jacket water cooling systems. They are also used in marine chilled water cooling systems, and may be used in liquid-cooled hydrogen fuel cell cooling systems.
Walton supplies two types of 3-way temperature control valves:
- Self-acting thermostatic valves in which a temperature sensor inside the valve moves a rotor which proportions the fluid flow. These are sometimes known as thermostatic, or direct operated, valves.
- Externally-actuated valves in which the rotor is moved by an electric or pneumatic actuator mounted on top of the valve. A further variant of this is the Walton gas operated valve in which refrigerant gas pressure provides the external actuation.
Self acting valves
Self acting (direct operated) valves incorporate a temperature sensor inside the valve, and operate independently of external power supplies.
Electrically operated valves
Electrically operated valves are powered by an external electric actuator, with control provided by a separate electronic control unit, and temperature sensing by remote transmitter, transducer or resistance thermometer.
Pneumatically operated valves
Pneumatically operated valves are powered by an external pneumatic actuator, with control provided by a pneumatic controller with external temperature sensing.
Gas operated valves
Gas operated valves are designed to control refrigerant gas pressures – and hence the temperature of refrigerated or air-conditioned areas – in marine systems in which the condenser is cooled by sea water.
Mixing or diverting
Walton valves may be installed to either mix fluids from two inlets and discharge through a single outlet (mixing), or to divide the flow from one inlet into two outlets (diverting).
When operating in mixing mode, the temperature control valve is fitted downstream of the cooler. The hot (bypass) and cold (cooler) fluid streams enter two valve ports in proportions determined by the position of the valve’s rotor, thereby maintaining the temperature of the fluid leaving the third port at the required temperature.
When operating as a diverter, the valve is fitted upstream of the cooler. The inlet from the heat source enters one port and is divided into two outlet streams to the cooler and bypass in proportions determined by the position of the valve’s rotor. This maintains the temperature of the fluid returning to the heat source at the required temperature.
In most applications it is recommended that the temperature control valve is fitted downstream of the cooler to operate as a mixing valve.
Most Walton valves can be supplied in any of six possible port configurations (called handings) to suit your preferred pipework layout. This provides great flexibility as the valve can be supplied to suit the pipework, rather than the pipework having to be adapted to suit the valve.
See the separate product pages for details of the port configurations available.
We are always willing to create a customised solution for your application if none of our standard products are suitable
Our advanced computer aided design software and the flexible nature of the Walton valve design mean that this can often be a cost-effective approach.