The Yoshitake GP-1200S is a pilot-operated, pneumatic remote type pressure reducing valve designed for steam applications. It is well suited for systems where the pressure setting is frequently changed or for centralized control systems. The "S" designation indicates that its main internal components (piston and cylinder) are made of stainless steel for enhanced durability and corrosion resistance.

Features

• Significantly improved workability and durability compared with conventional pressure reducing valves.
• Spherical main valve offers great sealability and a great reduction of valve seat leakage (compliant with ANSI Class IV).
• Compliant with SHASE-S106 Pressure Reducing Valves (Society of Heating, Air-Conditioning and Sanitary Engineers of Japan).
• Simple and robust internal structure.
• Pneumatic, remote type valve suitable for centralized control systems.

Specifications

Specification	Value
Application	Steam
Inlet Pressure	0.1–1.0 MPa
Reduced Pressure	0.05–0.9 MPa (90% or less of inlet pressure)
Minimum Differential Pressure	0.05 MPa
Maximum Pressure Reduction Ratio	20:1
Maximum Temperature	220°C
Valve Seat Leakage	0.01% or less of rated flow
Body Material	Ductile cast iron
Valve / Valve Seat Material	Stainless steel
Piston / Cylinder Material	Stainless steel (GP-1200S specification)
Connection	JIS 10K FF Flanged

Dimensions and Weights

Nominal Size	L (mm)	H1 (mm)	H (mm)	Weight (kg)
15A	150	64	220	8.0
20A	155	64	220	8.5
25A	160	67	235	10.0
32A	190	82	258	14.0
40A	190	82	258	14.5
50A	220	93	282	20.0
65A	245	100	292	30.0
80A	290	122	339	35.0
100A	330	144	385	52.5

Operation

The GP-1200S reduces pressure by throttling the main valve. It is composed of a main valve for throttling, an air pressure control space, a diaphragm, a pilot valve, and a piston for pressure sensing and activation.

1. When air pressure is zero, the main valve and pilot valve are closed by spring force.
2. Introducing air pressure into the air chamber flexes the pilot diaphragm to open the pilot valve.
3. Inlet pressure enters the upside of the piston via the pilot valve, overriding the pressure on the downside and the main valve spring, which opens the main valve.
4. Reduced pressure is led to the diaphragm chamber, balancing with the air loading pressure to control pilot valve travel.

Sizing and Selection

Standard Loading Pressure-Setting Pressure

The setting pressures corresponding to the loading pressure may deviate slightly depending on conditions like the length of the air line. Select a setting pressure high enough to cover such deviations.

Safety Valve Setting Pressure

Determine the reduced pressure, find the intersection with the chart curve, and proceed horizontally to the safety valve axis. The safety valve setting must be higher than this point.

Installation Precautions

Handling and Piping

• Hold the valve with lifting equipment during piping due to its heavy weight.
• Install a strainer (80 mesh) at the valve inlet side to ensure correct pressure control.
• Install a steam trap at the inlet side to prevent drainage problems.
• Ensure the valve is installed perpendicularly to horizontal lines in the proper direction of fluid flow.

System Layout

• Install pressure gauges at both the inlet and outlet sides.
• Provide a bypass line for maintenance.
• Leave sufficient space above and below the valve for easy disassembly and inspection.
• When using quick open/close valves (like solenoid valves) or reducing pressure in two stages, secure at least 3 m of distance from the GP-1200S.

Maintenance and Disassembly

Safety Warning

Completely discharge internal pressure from valves and lines, cool the valve down so it can be touched with bare hands, and set operating air pressure to zero before disassembly and inspection.

Recommended Replacement Periods:

• Diaphragm / Pilot diaphragm: 2 years
• Gaskets: 2 to 5 years (replace with new ones every time the valve is reassembled)
• Piston ring / Inner ring: 3 years
• Pilot valve assembly / Strainer: 5 years