Cooling type self regulating temperature control valve modulates the flow of a cooling medium such as water in response to process temperature, opening to admit coolant as the process heats up and closing when the setpoint is reached, with no instrument air, electrical supply or controller.
Product Description
The valve combines three elements in one unit: a control valve, a thermal actuator, and a temperature controller with a fixed setpoint adjustment. It is intended for non-corrosive liquids, gases and steam on the process side, and it does one job: keep the temperature of a vessel, a cooler or a process stream near its setpoint by throttling the flow of cooling medium to it.
The control action comes from thermal expansion of a liquid inside the sensing bulb, and it is a proportional action, but the valve is arranged to open on heating rather than close. When the process temperature rises above the setpoint, the bulb liquid expands, the force on the actuator stem grows, and the plug opens to increase the flow of water or other cooling medium. As the process cools to the setpoint, the bulb liquid contracts and the plug closes, cutting the coolant off until it is needed again. Valve travel follows the difference between actual and setpoint temperature, so the valve settles at whatever opening removes the heat load. The flow characteristic is quick opening. The standard setting range is 40 to 100 °C, with settings above 100 °C available, and control deviation is within ±2.5 °C.
Two details are worth attention at selection. The trim is pressure balanced, bellows balanced on the smaller sizes and cage balanced on the larger, so the actuator holds control authority against the differential across the valve without becoming oversized; the allowable differential is 1.6 MPa up to DN 150, reducing to 1.5 MPa at DN 200 and 0.5 MPa at DN 250. And the sensing bulb must be installed where it sees the controlled temperature: fully immersed, in representative flow, connected through a capillary of 3 m or 5 m. The time constant is approximately 70 seconds for the bare bulb and 120 seconds with the protective jacket, which suits vessels, tanks and circulating cooling duties.
This page covers the cooling type, which opens the valve as process temperature rises and admits coolant. Where the duty requires the valve to close on rising temperature in order to throttle a supply of steam, hot water or thermal oil, the heating type of the same series is the correct selection.
Key Features
- No external energy: the valve is driven entirely by thermal expansion of the bulb fill, with no instrument air, no electricity and no controller.
- Opens on temperature rise: action is arranged for cooling duty, so a power failure simply freezes the valve in place and the coolant path does not slam shut on a hot process.
- Pressure balanced trim: bellows or cage balance limits the effect of differential pressure on the plug, giving high sensitivity and stable control at high ΔP.
- Accurate and protected: control deviation within ±2.5 °C, and the setpoint adjuster carries over-temperature protection; process temperature may exceed the setpoint by up to 20% without damage.
- Low noise and maintenance free: balanced trim and low travel speeds keep operating noise down; there are no wearing power components to service.
- Modular construction: standardized modules allow trim and seal parts to be exchanged, and combinations of modules support compound control duties.
Typical Applications
- Jacketed vessels and reactors in cooling service: cooling water throttled to hold batch temperature.
- Compressor, engine and pump cooling circuits: holding jacket water temperature within a band at the point of use.
- Oil coolers and heat exchangers: regulating cooling water flow on the utility side.
- Process water and wash water cooling: simple proportional temperature regulation on utility services.
- Industries served: oil and gas, chemical, power generation, metallurgy, food, pharmaceutical and light industry.
A self operated cooling valve is usually chosen for the same reason as any self operated regulator: there is no signal chain to fail, no power to lose, and nothing to configure. We confirm the setting range, the seal type and the differential pressure against your duty, and we will say so plainly when a duty needs a transmitter, a controller and an actuated control valve instead.
Technical Specifications
| Valve Size | DN 15, 20, 25, 32, 40, 50, 65, 80, 100, 125, 150, 200, 250 |
|---|---|
| Flow Coefficient KV | 3.2, 5, 8, 12.5, 20, 32, 50, 80, 125, 190, 280, 420, 500 |
| Pressure Rating | PN16, PN25, PN40 |
| Maximum Medium Temperature | 220 °C |
| Control Action | Proportional; opens on rising temperature, closes on falling temperature |
| Temperature Setting Range | 40 to 100 °C; settings above 100 °C available |
| Setpoint Deviation | ±2.5 °C |
| Allowable Overload | Within 20% above the setpoint |
| Pressure Balance | Bellows balanced or cage balanced, by valve size |
| Flow Characteristic | Quick opening |
| Bulb Nominal Pressure | 6.4 MPa |
| Time Constant | Approx. 70 s bare bulb; approx. 120 s with protective jacket |
| Capillary Length | 3 m or 5 m |
| Bulb Connection | R 1 1/4" |
| End Connections | Flanged, ASME B16.5 or JIS B2201 |
| Seat Leakage, Metal Seal | Class IV (single seat trim), Class III (cage trim) |
| Seat Leakage, Soft Seal | 10 bubbles/min (DN 15 to 50), 20 bubbles/min (DN 65 to 125), 40 bubbles/min (DN 150 to 250) |
| Allowable Differential Pressure | 1.6 MPa up to DN 150; 1.5 MPa at DN 200; 0.5 MPa at DN 250 |
| Power Requirement | None, self operated |
| Media | Non-corrosive liquids, gases and steam; cooling media: water and other non-corrosive coolants |
Frequently Asked Questions
How is the cooling type different from the heating type?
Both use the same thermal expansion bulb and the same valve bodies, but the action is reversed. The cooling type opens as process temperature rises, admitting water or another coolant. The heating type closes as temperature rises, throttling the supply of steam, hot water or thermal oil. The action must be specified when ordering.
What does it do when the process gets too hot?
It opens. As temperature rises past the setpoint, the bulb liquid expands and drives the plug open, increasing the flow of cooling medium until the temperature returns to the setpoint. The valve tolerates process temperature up to 20% above the setpoint without damage.
How accurate is it?
Control deviation is within ±2.5 °C. The action is proportional, so the valve settles at an opening that removes the heat load rather than snapping fully open or closed.
How far can the sensing bulb be from the valve?
The capillary is supplied in 3 m or 5 m lengths. The bulb must be fully immersed in representative flow, not in a dead leg, and the response time is approximately 70 seconds bare or 120 seconds with the protective jacket.
Metal seat or soft seat?
Metal sealing gives Class IV leakage on the single seat trim and Class III on the cage trim, and it suits continuous cooling service. Soft sealing reduces leakage to a bubble count of 10 per minute on DN 15 to 50, 20 per minute on DN 65 to 125 and 40 per minute on DN 150 to 250, for duties where the coolant must be shut off tightly between cooling periods.
Resources
Data Sheets:
Manuals: IOM
Product Photos:
