HD/HSP Series | Regulators | Watson McDaniel

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HD/HSP Series

Pilot-Operated Regulators

The HD-Series Pilot-Operated Regulators are used on steam applications for pressure reduction or controlling product temperature (when steam is used in heating applications). The Pilot-operated regulators are more accurate and available in higher capacity than Direct-Operated regulators. The HD Series regulators use a pilot valve (several types and styles including Pressure, Temperature, ON-OFF solenoid, etc) to control the operation of the Main Valve. The HD series has a Ductile Iron Body; Pilot and Main-Valve are selected separately.

Building an HD Pilot-Operated Regulator

A complete HD Series regulator consist of a main valve and an operating pilots(s). Each are selected separately.

Reducing Pressure

The PP & PP5 Pilots referred to as spring loaded pressure pilots because an adjustable control spring to apply the opening force to the pilot valve. The opening and closing of the pressure pilot controls the operation of the Main Valve. Pressure adjustment screw is located on top of pressure pilot. The PA Air-Loaded Pressure Pilot uses air pressure to apply opening force to the pilot valve. The PA pilot allows for convenient and remote adjustment of steam pressure using a small air regulator.

Controlling Temperature

When steam is required for a heating applications, a temperature pilot is used. The PT pilot (most common) is referred to as a “solid liquid fill” and contains a temperature probe connected by a length of capillary tubing to a bellows in the pilot valve. When the temperature bulb is heated the liquid inside the probe expands the bellows and closes off the pilot valve. The PT Pilot is adequate for most temperature applications. Watson also offers the PTRP Pilot which works on vapor tension and has a quicker response time.

Controlling Temperature & Limiting Pressure to a Maximum Value

The PT & PP Pilot combination is used when it’s required to control temperature while limiting downstream pressure to a maximum value. The downstream pressure is limited to a maximum setting by the pressure pilot, while the temperature pilot maintains the correct temperature of the process.

HD Main Valve Selection

The HD-Series Pilot-Operated Regulators is for pressure reduction or temperature control in steam service applications. The complete regulator is comprised of the main valve and separate pressure or temperature pilot that controls the operation of the main valve. When both a pressure and temperature pilot are used together an additional pilot adapter is required.

These Model Codes are for HD Main Valve ONLY, control Pilot must be ordered separately.

Ordering Instruction:

Select the appropriate main valve size to handle the required capacity. The flow capacity is determined by Inlet pressure, Outlet pressure and valve size.
When sizing valves for temperature control application assume that outlet pressure in the heat exchanger is 50% of inlet pressure to the valve. For example: If inlet pressure is 50 PSI outlet pressure is assumed to be 25 PSI.
If inlet pressure is under 15 PSI the LP (Low Pressure) option for main valve must be used. Example: HD-12-N-LP
Select the appropriate pilot for pressure reduction or temperature control from pilot section.

Example Model Codes for Main Valve:

HD-15-N
(HD Series Valve with 1-1/4: Threaded, NPT connections)
HDR-16-F150
(HD Series Valve, Reduced Port with 1-1/2” 150# Flanged connections)
HD-20-F300-SSXT
(HD Series valve with 4” 300# Flanged connections & SS External tubing)

STANDARD Main Valve:

Inlet Pressure: 15-300 PSIG
Example Model Code: HD-12-N

LOW-PRESSURE Main Valve:

Inlet Pressure: 5-20 PSIG
Example Model Code: HD-12-N-LP

Stainless Diaphragm Option

The HD regulator is supplied standard with a high tensile strength Phosphor Bronze diaphragm which has been determined thru experience and testing to be the absolute best diaphragm material choice for steam applications. Stainless Steel diaphragms are offered as an option because certain industry specifications have been written requiring stainless steel. Note: Stainless steel is prone to work hardening and will not last as long as phosphor bronze; only use if required by the specification to do so.

Stainless Tubing Option

Copper tubing is supplied as standard. Copper tubing offers excellent corrosion resistance and is easy to bend and manipulate and normally outlasts the life span of the valve. Stainless Steel tubing is offered as an option.

Reduced port trim Option

Regulators should be sized to meet the application not to fit the pipe size. Over sizing a regulator may cause overshoot which leads to erratic pressure or temperature control often referred to as “hunting.” A valve with reduced port trim has a reduced seat and disc size for a given pipe size, (refer to capacity charts)

Low Pressure (Differential and inlet) Option

Regulators require a minimum Inlet pressure as well as a minimum pressure drop across the valve to operate properly. The HD Standard Main valve requires a minimum inlet pressure of 15 PSIG and minimum differential pressure of 10 PSI. The Low Pressure Main valve requires 5 PSIG minimum inlet pressure and 3 PSI minimum differential pressure. Low pressure main valve uses a EPDM diaphragm.

Pilot-Operated Regulators

Model Code for Main Valve: HD-17-F150
(2” HD Series Valve with 150# Flanges)

Model Code for Pilot: PP-B
(Pressure Pilot with 20-100 PSIG Range)

Model Code for Main Valve: HD-17-F150
(2” HD Series Valve with 150# Flanges)

Model Code for Pilot: PTU-14-8
(Temperature Pilot (100-160 ºF) with 8 Ft. Capillary)

HD Regulator - Pilots Selection

The HD Series Pilot-Operated Regulating Valve was designed for control of temperature and pressure in steam service applications. Several different control pilots can be mounted to the valve to control pressure, temperature, or a combination of both. When two or more pilots are used together (both a pressure and a temperature pilot) an additional pilot adapter for the second pilot is required (must indicate when ordering). The most common pilots are the PP-Pilot for pressure reducing, and the PT-Pilot for temperature control. The Main Valve and Pilot are purchased separately.

PRODUCT MODELS	APPLICATION	RANGE
PRESSURE PILOTS	Spring-loaded pressure pilot for general service pressure reducing applications.	Inlet: 5-300 PSIG Outlet: 3-200 PSIG
PRESSURE PILOTS	The Air-loaded Pressure Pilot can be used when frequent, quicker or easier adjustability of steam pressure is desired or when main valve is located remotely from where pressure adjustment takes place. Steam pressure control is done thru adjustment of a small air regulator that controls air pressure to the top of the pilot.	Inlet: 5-300 PSIG Outlet: 3-200 PSIG
TEMPERATURE CONTROL PILOTS	General purpose liquid-filled temperature pilot are used when heating vats or tanks of liquids to a desired temperature.	Inlet: 5-300 PSIG Temperature Control: 60-300ºF
TEMPERATURE CONTROL PILOTS	Special purpose vapor tension temperature pilot are used when a faster temperature response time is required.	Inlet: 5-300 PSIG Temperature Control: 20-440ºF
BACK PRESSURE PILOTS	For controlling upstream pressure of the HD Regulator.	Inlet: 5-300 PSIG Outlet: 3-200 PSIG
DIFFERENTIAL PRESSURE PILOT	Differential Pressure Pilot with two separate sensing ports for maintaining differential pressure between steam and an alternate medium.	Inlet: 5-300 PSIG Outlet: 3-200 PSIG
ON / OFF PILOT	Solenoid Pilot can be used in conjunction with any of the listed pilots for electrical on/off control of HD Regulators.	Inlet: 250 PSIG Pressure Range: PS1: 0-180 PSIG PS2: 180-250 PSIG

Reducing Pressure

A pressure control pilot is required when reducing pressure in a steam application. The downstream pressure is connected to the pressure pilot thru the sensing line. When the downstream pressure equals the set pressure the control pilot is forced closed which in turn closes the main valve. The PP & PP5 are spring loaded pressure pilots because an adjustable control spring is used to apply the opening force to the pilot valve. Pressure adjustment screw is located on top of pressure pilot. The PA pilot is referred to as an Air Loaded pressure pilot because Air Pressure is used to apply the opening force to the pilot valve. The PA air-loaded pilot allows for convenient and remote adjustment of steam pressure using a small air regulator.

The PA-Air Pilot is being used in conjunction with the PL2 Control Panel Board to regulate steam pressure. A small air regulator on the panel board can be adjusted to control the air pressure to the pilot. Steam pressure is controlled by the air pressure signal to the pilot. Depending on the air pilot model chosen (PA1, PA4, PA6), there will be a 1:1, 4:1, or 6:1 ratio of outlet steam pressure to air pressure.

Controlling Temperature

When controlling steam flow to maintain a specific temperature, a temperature pilot is used. The PT-Temperature Pilot is referred to as a “solid liquid fill” and contains a temperature probe connected by a length of capillary tubing to a bellows in the pilot valve. When the temperature bulb is heated the liquid inside the probe expands the bellows and closes off the pilot valve. The PTRP-Temperature Pilot operates in a similar fashion except this style is referred to as a vapor-tension unit.

Controlling Temperature & Limiting Maximum Pressure

The PT & PP Pilot combination is used when it’s required to control temperature while limiting downstream pressure to a maximum value. The downstream pressure is limited to a maximum setting by the pressure pilot, while the temperature pilot maintains the correct temperature of the process.

Combination Pilots

The HD-Series Steam regulating valve can be used with up to three pilots simultaneously to control the operation of the valve. An example is when steam i s used to heat water in a Heat Exchanger. The Temperature Pilot will maintain precise control of outlet water temperature by controlling the amount of steam flow through the valve while a Pressure Pilot limits the maximum outlet steam pressure of the regulator to the Heat exchanger. A third pilot (Solenoid pilot) can be added to electrically activate or de-activate the system.

How HD Regulator Pilots Work

The HD Series Pilot-Operated Regulating Valve was designed for control of temperature and pressure in steam service applications. Several different control pilots can be mounted to the valve to control pressure, tempterature, or a combination of both. When two or more pilots are used together (both a pressure and a temperature pilot) an additional pilot adapter for the second pilot is required (must indicate when ordering). The most common pilots are the PP-Pilot for pressure reducing, and the PT-Pilot for temperature control. The Main Valve and Pilot are purchased separately.

Example: Controlling Pressure

The Pilot controls the opening and closing of the HD Main Valve. A sensing line connects the PP-Pressure Pilot to the downstream side of the regulator. Pressure in the sensing line applies an upward force to the pilot diaphragm to compress the adjustment spring. When downstream pressure equals the set point, the diaphragm moves upwards against the force of the adjusting spring, closing pilot valve. When the pilot valve is shut, steam cannot pass through to the underside of the regulator diaphragm, closing the regulator. When the steam pressure falls below its set point, the pilot valve opens allowing steam to lift the main valve diaphragm which opens the regulating valve.

Combination Pilots

The HD-Series Steam regulating valve can be used with up to three pilots simultaneously to control the operation of the valve. An example is when steam is used to heat water in a Heat Exchanger. The Temperature Pilot will maintain precise control of outlet water temperature by controlling the amount of steam flow through the valve while a Pressure Pilot limits the maximum outlet steam pressure of the regulator to the Heat exchanger. A third Solenoid pilot can be added to electrically activate or de-activate the system.

HD Main Valve Features

The HD Series Pilot-Operated Regulating Valve was designed for extremely accurate control of temperature and pressure in steam service applications. The HD Series is made of Ductile Iron for extended pressure and temperature ratings when compared to cast iron. The Standard Main Valve is used for an inlet steam pressure range of 15-300 PSIG. The Low-pressure Main Valve contains a different main valve spring and is available for an inlet pressure range of 5-20 PSIG.

Features of the HD Regulating Valve

No external power source is required
Additional Test Port for field diagnostics
Ductile iron body for higher pressure ranges and increased safety when compared to cast iron.
The innovative design allows the pilot to be mounted on either side of the regulator and is easily field-reversible without having to rebend tubing.

Pilot Adapter

The pilot adapter includes a full port strainer and blowdown valve for ultimate protection against dirt and scale, as well as more efficient start-ups. The innovative design allows the pilot to be mounted on either side of the regulator and is easily field-reversible without having to re-bend tubing. Pilots are easily installed on the pilot adapter using only 4 bolts – no tubing connections to the main valve are required to be made in the feild.

Seat & Disk

Hardened stainless steel trim (55 Rc) for extended life even in the most demanding applications.

Low Pressure & High Sensitivity

HD Series Configurator

HD Regulator - Main Valve

The HD Series Pilot-Operated Regulating Valve was designed for extremely accurate control of temperature and pressure in steam service applications. The HD-Series is made of Ductile Iron for extended pressure and temperature ratings. These regulators use several different control pilots which are mounted to the valve to control pressure, temperature or a combination of both. When two or more pilots are used at the same time - for example, both a pressure and a temperature pilot - an additional pilot adapter for the second pilot is required (must indicate when ordering).

HD Regulator - Pilots

HD Series Pilots are mounted to the HD Main Valve to control pressure, temperature or a combination of both. Several control pilots are offered:

Pressure Pilots
Temperature Pilots
Solenoid Pilots
Air Pilots

Pneumatic Temperature Controller
Back Pressure Pilots
Differential Pressure Pilots

HD Accessories

Acoustic Diffusers
Orifice Plates
Acoustic Silencers
Insulation Jackets
Remote Control Panel (PL Series)
Pilots - Adapters

HSP & HSP-SS Regulator - Integrated Pressure Pilot

The HSP Pilot-Operated Pressure Regulating Valve is constructed of Cast Carbon Steel for pressure and temperature ratings when compared to ductile iron. The HSP includes pre-mounted Pressure Pilot (similar to PP&PP5 Series) with full port strainer and blowdown Valve on pilot adapter for ultimate protection from dirt and scale. The HSP Pressure Regulator is more accurate than Direct-operated Regulators. The HSP-SS is an all stainless steel version for improved corrosion.