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Model W94Temperature Indicating (with indicating dial) will allow the operator to verify the process temperature and to aid in temperature adjustment.
Model W91Non-Indicating (without indicating dial) use where space constraints may be an issue.
Working Temperature Range:The recommended working span typically falls within the upper third of the nominal range. Using the valve in the recommended working span improves temperature response time of the system.
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. The union connection accepts standard threaded pipe.
Stainless Steel Bulb:Used for corrosive applications, however response time will be reduced when using stainless.
W91/W94: Cooling
The W91/W94 Self-Operating Temperature Regulator is a mechanically operated device designed to regulate system temperature by modulating the flow of a heating or cooling fluid in response to temperature changes; requires no external power source.
W91 & W94 Series - Cooling
Model W91 Non-Indicating (without indicating dial) use where space constraints may be an issue Model W94 (Suggested) Temperature Indicating (with indicating dial) will allow the operator to verify the process temperature and to aid in temperature adjustment.
The recommended working span typically falls within the upper third of the nominal range. Single-Seat In-To-Close, all Double-Seat, and all 3-Way valves have a recommended working span in this part of the nominal range. Using the valve in the recommended working span improves temperature response time of the system.
The sensing bulb and capillary are available in Copper (best heat transfer properties) or Stainless Steel (for corrosive applications). Copper has better heat transfer properties than stainless steel and should always be chosen for better temperature control unless used in corrosive service. The length of the sensing bulb is dependent upon the capillary length required (see chart). Longer capillary lengths require a longer length sensing bulb to operate the regulator. For installation, the Union Hub is threaded into a tank or piping system. The bulb slides through the Union Hub and is held in place by the Union Nut which spins freely around the armored capillary and threads into the Union Hub. The angled surface of the sensing bulb forms a metal-to-metal seal on the inner edge of the Union Hub to prevent leakage of the process fluid
NORMALLY CLOSED
Stem In-To-Close for COOLING
Thermowells isolate and protect the sensing bulb from the process fluid, and are available in either Brass (best heat transfer) or Stainless Steel (for corrosive applications). Thermowells allow for sensing bulb removal and replacement without having to drain liquid from the system. To maintain the best temperature control, always use a Copper Sensing bulb as opposed to a Stainless Steel sensing bulb. For corrosive applications, Stainless Steel thermowells (with a copper sensing bulb) can be used. Thermowells are also recommended for applications with excessive system pressures or extremely turbulent flow to protect the sensing bulb from damage. Thermowell Length must be selected based on the length of the sensing bulb. The sensing bulb length is based on the length of the Capillary used in the Thermal System. Longer capillary lengths require a longer sensing bulb to hold the additional actuator fluid inside the sensing bulb. Reference Sensing Bulb Chart for sensing bulb length.
Cooling Applications
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.
Reverse-Acting: Normally Closed Valves are used for COOLING, The actuators are designed to move the valve stem open (in-to-open) as the control signal (temperature) increases.