Description
Technical Specifications
Functional Features
- Direct-acting top-guided diaphragm design — downstream pressure acts directly on the diaphragm, modulating valve position without external sensing line
- Balanced trim configuration — minimizes the effect of inlet pressure fluctuations on downstream setpoint accuracy
- Adjustable spring range 0 to 60 psig — setpoint adjustable via handwheel on top of the actuator without disassembly
- Fail-closed action — spring forces valve closed on loss of supply pressure, providing inherent safety shutoff
- 144 square inch diaphragm area — provides high thrust for precise control under high-flow conditions
- PTFE soft seat — provides bubble-tight shutoff (Class IV leakage) with zero friction during valve opening
- Stainless steel 316 trim — resists corrosion from aggressive process fluids including steam, gas, and chemicals
- Top-guided diaphragm — eliminates side thrust on the valve stem, extends packing life, and ensures stable operation
- No external pilot required — self-operated design eliminates need for separate pilot regulator, reducing installation complexity
- Built-in downstream pressure sensing — sensing line is integral to the body, no external tubing required
- Compact 1/2 inch NPT design — fits standard piping systems without reducers
- FM/CSA approved — certified for use in hazardous locations per FM Class I, Division 2 and CSA Class I, Division 2
Performance Parameters
Material Composition
Structural Features
- Top-guided diaphragm actuator — diaphragm is guided by the bonnet, stem moves vertically without lateral deflection
- Bolted bonnet construction — allows diaphragm and seat replacement without removing the body from the pipeline
- Integral downstream sensing port — sensing line is cast into the body, connects directly to the diaphragm chamber
- Adjustable setpoint handwheel — located on top of the actuator, calibrated in psig with visible scale
- Threaded 1/2 inch NPT connections — female NPT inlet and outlet, no flanges required for 1/2 inch service
- Balanced plug design — plug has pressure-balancing holes that equalize force across the plug, reducing actuator load
- PTFE soft seat with metal-to-metal backup — primary seal is PTFE, secondary seal is stainless steel-to-stainless steel metal seat
- Spring cage assembly — spring is enclosed in a stainless steel cage to prevent failure in case of spring breakage
- Drain port — 1/4 inch NPT drain port on bonnet for condensation removal in steam service
- Lockable handwheel — setpoint adjustment can be locked with a padlock to prevent unauthorized changes
- Nameplate — permanent stainless steel nameplate with model number, serial number, pressure range, and certification marks
Working Principle
The Honeywell 05704-A-0144 operates as a direct-acting pressure regulator. Downstream process pressure is sensed through the integral sensing port in the regulator body and transmitted to the underside of the diaphragm inside the actuator. The diaphragm has an effective area of 144 square inches. The adjustable compression spring above the diaphragm exerts a downward force calibrated to the desired downstream setpoint pressure. When downstream pressure is below setpoint, the spring force exceeds the diaphragm force, pushing the valve open to allow more flow and increase downstream pressure. When downstream pressure rises above setpoint, the diaphragm force exceeds the spring force, pushing the valve closed to restrict flow and reduce downstream pressure. The valve continuously modulates between fully open and fully closed to maintain the downstream pressure at the setpoint. The balanced plug design ensures that inlet pressure variations do not significantly affect the force balance on the plug, maintaining setpoint accuracy. The PTFE soft seat provides a bubble-tight seal when the valve is fully closed. On loss of supply pressure or diaphragm failure, the spring forces the valve to the fully closed (fail-closed) position, providing inherent safety shutoff.
Advantages and Highlights
- Direct-acting design — no external pilot, no sensing line, no auxiliary equipment required
- Top-guided diaphragm — eliminates stem side thrust, extends packing life by 300% compared to side-guided designs
- Balanced trim — inlet pressure variations cause < 1% setpoint shift per 10 psig inlet change
- Fail-closed action — inherent safety shutoff on loss of supply or diaphragm failure
- PTFE soft seat — achieves ANSI Class IV bubble-tight shutoff with zero friction
- Adjustable setpoint without disassembly — handwheel on top allows field adjustment from 0 to 60 psig
- FM/CSA hazardous location approved — certified for Class I, Division 2 hazardous environments
- Compact 1/2 inch NPT design — fits standard small-bore piping without adapters
- 144 square inch diaphragm area — high thrust for stable control under high-flow, high-differential conditions
- Stainless steel 316 wetted trim — resists corrosion from steam, gas, and chemical process fluids
- Lockable handwheel — prevents unauthorized setpoint changes in critical applications
- Integral drain port — allows condensate removal in steam service without external piping
- Long diaphragm life — Buna-N/Neoprene diaphragm rated for > 5 years continuous service
- No external power required — purely pneumatic/mechanical operation, zero electrical consumption
Applicable Industries
Model Series Comparison (Honeywell 05700 Series)
Installation Requirements
- Mounting Orientation: Install vertically with actuator on top, diaphragm horizontal, in a position that allows drainage from the bonnet
- Piping Support: Provide independent pipe support on both inlet and outlet; do not allow regulator body to bear pipe weight
- Upstream Straight Run: Minimum 10 pipe diameters of straight pipe upstream of the regulator
- Downstream Straight Run: Minimum 5 pipe diameters of straight pipe downstream of the regulator
- Pressure Gauge Installation: Install pressure gauges on both inlet and outlet sides of the regulator for commissioning and monitoring
- Isolation Valves: Install block valves upstream and downstream of the regulator for maintenance isolation
- Bypass Line: Install a manual bypass valve in parallel with the regulator for continuous service during maintenance
- Drain Connection: Connect the 1/4 inch NPT drain port on the bonnet to a drain line sloped downward for condensate removal
- Inlet Pressure: Ensure inlet pressure is 80 to 150 psig; do not exceed 150 psig maximum inlet pressure
- Differential Pressure: Maintain minimum 3 psid differential across the regulator for proper regulation
- Thread Sealant: Use PTFE thread tape or pipe dope on all NPT connections; do not use teflon tape that shreds into the flow path
- Torque Specifications: Tighten bonnet bolts to 25 ft-lbs (34 Nm) in a star pattern; do not exceed 30 ft-lbs (41 Nm)
- Handwheel Lock: If required, install a padlock through the handwheel lock holes to prevent unauthorized setpoint adjustment
- Ambient Conditions: Install in an environment between -40°F to +150°F (-40°C to +66°C); protect from direct sunlight and weather exposure
- Hazardous Area: For Class I Division 2 installations, verify FM/CSA certification matches the hazard classification; use approved wiring methods
Usage Precautions and Notes
- Never operate the regulator with inlet pressure exceeding 150 psig — overpressure causes diaphragm rupture and uncontrolled flow
- Never operate with less than 3 psid differential pressure — insufficient differential causes hunting and unstable control
- Do not use the regulator for liquid service without a strainer upstream — particulate matter damages the PTFE seat and causes leakage
- Do not exceed the rated flow capacity (Cv 8.0) — oversized flow demand causes chattering and premature seat wear
- Adjust setpoint only with the regulator in service and at operating pressure — adjusting at zero pressure causes inaccurate calibration
- Lock the handwheel after setpoint adjustment in critical applications to prevent drift from vibration or accidental contact
- Perform annual inspection of the diaphragm — replace the diaphragm if any cracks, bulges, or hardening are observed
- Replace the PTFE seat every 5 years or immediately if leakage exceeds ANSI Class IV limits
- Do not weld on the regulator body — heat damage to the diaphragm chamber and internal components
- Do not use the regulator as an on/off shutoff valve — it is designed for continuous modulation; frequent full-stroke cycling reduces life
- Verify the correct spring range is installed — installing a 15-150 psig spring in a 0-60 psig body causes incorrect setpoint and potential overpressure
- Drain condensate daily in steam service — water hammer from trapped condensate damages the diaphragm and seat
- Do not apply pipe dope to the drain port threads — excess dope can block the drain and cause water hammer
- All installation must comply with local codes and NFPA 54 (National Fuel Gas Code) for gas service
- Commission the regulator with a calibrated pressure gauge — verify setpoint accuracy is within ±3% before placing in service
- Do not disassemble the regulator in a hazardous atmosphere — depressurize and purge before any maintenance
- Store spare regulators in a dry, climate-controlled environment — Buna-N diaphragms degrade in UV light and ozone; keep in original packaging
- All installation and commissioning must be performed by a licensed gas fitter or process technician per NFPA 54 and ASME B31.3 requirements
Reviews
There are no reviews yet.