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  • PTRP-400x400
  • PTRP-a-400x400
  • PTRP-b-400x400
Technical Specification
Max. Inlet Pressure (psig)300
Temperature Control Range225 - 370°F (107 - 188°C)
Material Specification
Pilot BodyCast Steel
ValveStainless Steel
SeatStainless Steel
Support BracketAluminum
All Other PartsBrass
Product Overview
The PTRP-Temperature Pilot is used with the HD Regulator to control temperature in various processes and systems. The PTRP uses a vapor tension system to actuate the bellows in the temperature pilot giving it a faste r reaction time and better temperature sensitivity than the standard PT pilot. They can be used on: oil heaters, ovens, process heaters, vats, dryers, jacketed kettles, and semi-Instantaneous water heaters.
• Stainless steel valve and seat
• Standard bulb & capillary is copper, which has the best heat transfer properties .
• Standard capillary length is 8 ft. with 316 stainless steel armour- protection
How It Works
HD Valve with PTRP Temperature Pilot Application

A semi-instantaneous steam-to-water heater is a common application where the simple benefits of a self-contained, pilot-operated regulator with temperature sensing pilot may be favored over more complex and expensive control valves. The thermally sensitive bulb of the PTRP pilot contains a fluid that creates a vapor which increases or decreases in pressure as the sensing bulb – sensing the heated water – temperature increases or decreases. This vapor pressure is transmitted hydraulically to the bellows, which actuates the pilot and HD regulator to control the flow of steam into the heater. At start-up, the pilot is manually adjusted to raise the temperature set point and allow steam to flow through the  pilot and valve. As the heated water nears the temperature set point, the vapor pressure in the sensing bulb increases and expands the bellows, closing the pilot and regulator to proportionally limit the steam supply.
Selection / Sizing / Capacities

Model Coding for PTRP Pilot

Standard PTRP-Pilot

The most common pilot configuration is the PTRP-94 with copper sensing bulb 8’ capillary with stainless steel armored protection. Thermowell (Isolation well) is purchased separately if required for the application.

Options & Adders

Code LP - Low-Pressure Pilot: Required for steam pressures less than 15 psig. A low pressure main valve is also required.

Capillary Lengths: 8’ length is standard, available in 8‘, 12’, 16‘, 20’ & 24‘ lengths. 20’ and 24’ lengths require an extended length sensing bulb.

Corrosive Applications: Sensing Bulb, Thermowell and Capillary are available in 316 SS for corrosive applications, however response time will be reduced when using stainless. Using 316 SS thermowell with copper sensing bulb is a preferable choice.

Thermowell (Separable Socket):
• Available in copper for quicker response time or 316 SS for corrosive applications.

Temperature Indicating Dial:
• will allow the operator to verify the process temperature and to aid in temperature adjustment. (for Models PTRP-94)

SDWA Compliance (Safe Drinking Water Act); Consult Factory.

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.

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.

Dimension and Weights

• Capillary Lengths: Available in 8, 12, 16, 20 & 24-ft.
• Special Materials: Sensing bulb, thermowells, and capillary are available in special corrosion resistant materials.
  - 316 stainless steel capillary, bulb & bushing
  - 316 stainless steel armor with standard capillary
• Thermowell (Separable Socket): Available in stainless steel or copper
• Temperature Sensing Dial: Indicates temperature of process being controlled
• SDWA Compliance (Safe Drinking Water Act); Consult factory