Heating Fuel Oil to Proper Temperature

When the Sensing Bulb is mounted remotely from the actual point of heating (as shown) the Circulation Pump MUST continue to run so that the sensing bulb can sample the product temperature in the heat exchanger. Without product circulation, the temperature control valve will never shut off and the oil will be overheated.

Elevating Temperature of a Plating or Finishing Tank

Sensing bulb should be properly placed inside tank for best temperature consistency. An optional Thermowell (Stainless Steel or Brass) may slightly reduce temperature sensitivity. However, it will isolate sensing bulb and allow for its removal without draining the tank.

Drying Oven Application

W94 Valve used to regulate the temperature of the air flow through an air heating duct. The sensing bulb is installed toward the end of the heating duct and will sense the temperature of the air flowing past the heating coils. When air temperature is below the set point, the valve will open to allow more steam through to the coils to heat the air passing through the duct. Once the desired air temperature is achieved, the valve will begin to modulate closed to maintain the air temperature.

Reduce Oil Temperature In a Heat Exchanger

W91 Cooling valve controlling the flow of water through a heat exchanger to maintain the temperature of oil that is gaining heat by some process. The valve automatically shuts off when not required, greatly reducing cooling water usage. The source of the cooling water may be a well or city water supply and it can be circulated or dumped to drain. A 3-way valve may be used on cold water chiller systems so flow can be diverted from going through the heat exchanger when not required.

Control Water Flow to Air Compressor for Cooling Purposes

When the Sensing Bulb is mounted remotely from the actual point of Cooling (as shown), the water MUST continue to flow so that the sensing bulb can sample the product temperature of the unit being cooled. Without continuous water flow, the temperature control valve will never turn on, causing the unit to overheat. The bypass line provides a minimum continuous flow when temperature set point is achieved and the valve is closed.

The W91/W94 Temperature Regulator is a fully self-contained unit requiring no external power source (i.e., compressed air or electricity). Regulation takes place when the sensing element (bulb) of the thermal system is exposed to changes in temperature. The thermal system is charged with a predetermined amount of vapor fill, which, when heated, will cause the bellows within the unit’s actuator housing to expand pushing the valve stem downward. When a heating valve is used this action will close the valve. When a cooling valve body is used this will open the valve.

The housing consists of a cap and yoke constructed from precision die cast aluminum. This assembly ensures permanent alignment with the valve body, while protecting the bellows assembly. The yoke includes a set-point scale used to reference the setting of the temperature adjustment screw. The entire housing is finished in a corrosion resistant, baked grey epoxy.

The accordion type bellows is corrosion resistant to provide accurate response for the life of the regulator. An adjusting bar is provided to turn the brass temperature adjustment screw, which compresses or expands the range adjustment spring, thereby setting the control-point of the unit.

Care must be taken to ensure that the entire length of the sensing bulb is immersed into the medium at the sensing location. Partial immersion of sensing bulb in the process fluid can result in faulty control. The sensing bulb is designed to be installed in either a horizontal or vertical or orientation (with the tip down). If the tip must be installed upwards, please specify when ordering, as a special bulb construction is required. The sensing bulb material is available in either copper (best heat transfer) or stainless steel (corrosion resistant) and must be compatible with the process fluid, or an optional thermowell can be used for complete isolation of the sensing bulb from the process fluid.

Thermowells isolate the sensing bulb from the process fluid. For applications in which the process media may be corrosive or contained under excessive pressure, the use of a thermowell is required to prevent damage to the sensing bulb. A thermowell also allows the removal of the sensing bulb without having to rain liquid from the system. Thermowells are available in either brass (best heat transfer) or stainless steel (for corrosive applications). The 1-1/4” NPT hub of the thermowell can be installed into the side of a tank or female pipe connection, depending on the application. Three different length thermowells are available to match sensing bulb lengths.

To ensure minimum response time, Heat Transfer Paste (supplied with thermowell) should be applied to the sensing bulb prior to installation.

Single-seated balanced valves are used on heating applications (most commonly steam) where tight shut-off is required. Double-seated valves are used on cooling applications because of the high flow rates of cooling water that are often required. The balanced double- seated design also allows the temperature actuator to operate with higher differential pressures than would be possible using single-seated non-balanced valves. 3-way valves are used for mixing and diverting applications.

The Valve body is selected based on the application it will be used for Heating - Cooling - Mixing-Diverting . Valve bodies used for heating are normally open allowing flow, and will close when the sensing bulb reaches the set temperature. Valve bodies used for cooling are normally closed and will open when the sensing bulb reaches the set point.

Connection Type:
Valve bodies are available with NPT Threaded and Flange connection depending on size.

Integral Union:
Valve Bodies are also available with an integral union built into the valve body The union connection saves space and allows for convenient installation and removal, if replacement is required. The union connection accepts standard threaded pipe.

Normally Open Valves are used for HEATING. The valve stem is pushed closed (in-to-close) when the sensing bulb increases in temperature and reaches the set point.

Single-Seated Balanced Valve are used for Heating Applications (normally steam) where tighter shut-off is required. Leakage rate is approximately 0.01% of the maximum capacity (Class IV shut-off).

Normally Closed Valves are used for COOLING. The valve stem is pushed open (in-to-open) when the sensing bulb increases in temperature to the desired set point.

Double-Seated Balanced Valve are used for Cooling Applications where larger flow rates of water are frequently required, and a small leakage rate through the valve is normally acceptable. Leakage rate can be up to 0.5% of the maximum valve capacity (Class II shut-off).