Yoshitake GP-1000S pilot-operated pressure reducing valve is a high-performance solution designed for steam applications. It features a durable ductile cast iron body combined with stainless steel trim components (piston and cylinder) to enhance longevity and reliability. The spherical main valve design ensures exceptional sealability, greatly reducing valve seat leakage to comply with ANSI Class IV standards.

Features

• Significantly improved workability and durability compared with conventional pressure reducing valves.
• Spherical main valve offers great sealability and maximum reduction of valve seat leakage.
• Compliant with SHASE-S106 Pressure Reducing Valves standard (by the Society of Heating, Air-Conditioning and Sanitary Engineers of Japan).
• Simple and robust internal structure for easy maintenance.

Model Code Description

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
Connection	JIS 10K FF Flanged
Body Material	Ductile cast iron
Valve & Valve Seat	Stainless steel
Piston & Cylinder (Trim)	Stainless steel (for GP-1000S)

Dimensions and Weights

Size	L (mm)	H (mm)	H1 (mm)	Weight (kg)
15A	150	285	64	8.0
20A	155	285	64	8.5
25A	160	300	67	10.0
32A	190	323	82	14.0
40A	190	323	82	14.5
50A	220	347	93	20.0
65A	245	357	100	30.0
80A	290	404	122	35.0
100A	330	450	144	52.5

Operation Structure

The pressure-reducing valve lowers pressure by throttling. It comprises the main valve and main valve seat for throttling, and an adjusting spring, diaphragm, pilot valve, and piston for pressure sensing and activation.

1. Releasing the compression of the adjusting spring allows it to close the main valve and pilot valve. As the gate valve slowly opens, high-pressure fluid enters the inlet and passes through the strainer to the downside of the pilot valve.
2. Turning the adjusting screw clockwise compresses the spring, flexing the diaphragm to open the pilot valve.
3. Inlet pressure enters the upside of the piston, overriding the main valve spring load to open the main valve, allowing fluid flow.
4. Reduced pressure enters the diaphragm chamber via the sensing port to balance the adjusting spring load and control pilot valve travel.
5. The pilot valve travel modulates fluid to the piston, controlling main valve travel to maintain the correct reduced pressure.

Nominal Size Selection

Example: For an inlet pressure of 0.6 MPa, reduced pressure of 0.4 MPa, and a steam flow rate of 800 kg/h, find the intersection point of 0.6 MPa and 0.4 MPa. Trace down vertically to the 800 kg/h flow rate. The point lies between nominal sizes 40A and 50A. Select the larger size: 50A.

Cv Correction Coefficient

If the inlet pressure exceeds 0.7 MPa, and the reduced pressure is 0.4 MPa or less, multiply the rated Cv value by the correction coefficient C from the chart below:

Nominal size	15A	20A	25A	32A	40A	50A	65A	80A	100A
Rated Cv value	1	2.3	4	6.5	9	16	25	36	64

Installation and Piping

Installation Precautions

• Install a strainer (80 mesh) at the valve inlet side.
• Install a safety valve at the outlet side to protect equipment.
• Provide a bypass line for maintenance.
• Ensure proper drainage by installing a steam trap at the inlet side.
• Provide sufficient space on the top and bottom of the valve for disassembly and inspection.

Maintenance and Disassembly

Consumable Part	Replace Period
Diaphragm	2 years
Piston ring & Inner ring	3 years
Pilot valve assembly	5 years
Gaskets	2 years
Strainer	5 years

Pressure Hazard

Before disassembling the valve, be sure that the stop valves at the inlet and outlet sides are closed and all internal pressure and condensate have been safely discharged.