2-1/2" Watson McDaniel W94-14-08S15-H18F125 Direct-Operated Temperature Regulators (For Heating With Steam), Die-Cast Aluminum Housing, 310 - 440°F (Heating), Temperature Indicating Dial (3-1/2"), 125# Flange

Watson McDaniel W94-14-08S15-H18F125 Direct-Operated Temperature Regulators For Heating With Steam, 310 - 440°F Indicating (2-1/2" 125# Flange)

Features:

• Self-Operating (No External Power Source Required)
• Temperature Indicating & Non-Indicating models available.
• Heavy Duty Die-Cast Aluminum Housing
• 1/2" Thru 4" Valve Sizes
• Fully Enclosed Bellows
• Temperature Over-range protection spring to protect thermal system.

Options & Features (See Specification Sheet For Full List):

W94 Series For Heating With STEAM

Direct-Acting: Normally Open Valves are used for heating with STEAM. The actuators are designed to move the valve stem closed (In-To-Close) as the control signal (Temperature) increases.

The W91 & W94 Self-Operating Temperature Regulators are the preferred choice of original equipment manufacturers, mechanical contractors and specifying engineers. They require no external power source and are ideal for regulating the temperature of tanks, process streams and various types of industrial equipment. The Actuator is noted for its rugged die-cast aluminum housing, fully-enclosed bellows assembly and internal over-temperature range protection.

• Model W91 Non-Indicating (Without Indicating Dial) features a lower profile and should be specified where space constraints may be an issue.
• Model W94 Temperature Indicating (With Indicating Dial) will allow the operator to verify the process temperature and to aid in temperature adjustment.

Temperature Range
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.

Capillary & Sensing Bulb
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.

Optional Thermowell
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.

How It Works

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. The valve action is either In-To-Close for Heating or In-To-Open for Cooling.

Normally Open Valves are used for HEATING, so the valve stem closes (In-To-Close) as the control signal (Temperature) increases.

Single-Seated Balanced Valves 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).

Selection / Sizing / Capacities