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.
• 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
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 Closed Valves are used for COOLING, so the valve stem opens (in-to-open) as the control signal (temperature) increases.
Double-Seated Balanced Valves 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).
Selection / Sizing / Capacities
Actuator Selection: The recommended working span for W91 & W94 Actuators 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.
| When Heat Load or Heat Transfer Rate (E) is Known |
Capacity of Steam Required(lbs/hr) |
= |
E _(btu/hr)
1000 |
| When Square Feet Equivalent Direct Radiation (EDR) is Known |
Capacity of Steam Required(lbs/hr) |
= |
Sq. ft. of EDR
4 |
| When Heating Water with Steam |
Capacity of Steam Required(lbs/hr) |
= |
GPM x Temp Rise (°F)
2 |
| When Heating Fuel Oil with Steam |
Capacity of Steam Required(lbs/hr) |
= |
GPM x Temp Rise (°F)
4 |
| When Heating Air with Steam Coils |
Capacity of Steam Required(lbs/hr) |
= |
CFM x Temp Rise (°F)
900 |