Yoshitake GP-1010S is a pilot-operated pressure reducing valve designed for steam applications. It features a simple and robust internal structure with a spherical main valve that offers great sealability and a significant reduction of valve seat leakage (compliant with ANSI Class IV). The "S" designation in the model code indicates that the trim parts (piston and cylinder) are made of stainless steel for enhanced durability.

The valve utilizes a JIS Rc screwed connection and is compliant with the SHASE-S106 Pressure Reducing Valves standard (by the Society of Heating, Air-Conditioning and Sanitary Engineers of Japan).

Specifications

Model	GP-1010S
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 Rc screwed

Material

• Body: Ductile cast iron
• Valve, valve seat: Stainless steel
• Piston, cylinder: Stainless steel (trim parts)

Dimensions and Weights

Nominal size	d	L	H1	H	Weight (kg)
15A	Rc 1/2	150	64	285	7.0
20A	Rc 3/4	155	64	285	7.0
25A	Rc 1	160	67	300	8.5
32A	Rc 1-1/4	190	82	323	12.0
40A	Rc 1-1/2	190	82	323	12.5
50A	Rc 2	220	93	347	18.0

Operation

No.	Parts name	No.	Parts name
1	Body	14	Piston
5	Diaphragm	15	Cylinder
8	Adjusting spring	19	Pilot valve
9	Adjusting screw	20	Pilot valve seat
11	Main valve	28	Strainer
12	Valve seat	42	Inlet pressure port
13	Main valve spring	43	Reduced pressure sensing port

The pressure is reduced through the throttling action (adiabatic expansion) of the pressure reducing valve. Its structure consists of the main valve and valve seat, which perform the throttling action, as well as the adjusting spring, diaphragm, pilot valve, and piston that regulate the operation.

1. When the pressure reducing valve is properly installed and the adjusting spring is in a free state, both the main valve and the pilot valve are closed by spring force. When the inlet stop valve is opened slowly, the high-pressure fluid enters, acting on the back of the main valve and passing through the strainer and inlet pressure port to act on the back of the pilot valve disc.
2. By turning the adjusting screw (or handle), the adjusting spring compresses and flexes the diaphragm, which pushes the pilot valve open.
3. The inlet pressure flows through the pilot valve seat and acts on the upper part of the piston. When this pressure overcomes the combined force of the inlet pressure under the main valve and the main valve spring, the main valve opens, allowing fluid to flow from the inlet side to the reduced pressure side.
4. A portion of the fluid on the reduced pressure side enters the diaphragm chamber through the reduced pressure sensing port. The diaphragm senses the reduced pressure and regulates the opening of the pilot valve while balancing the load from the adjusting spring.
5. The fluid flowing from the inlet pressure port changes the amount of fluid acting on the upper piston based on the pilot valve's opening, regulating the main valve's opening to maintain the correct reduced pressure.

Specifications Selection Chart

Find the intersection point of the inlet and reduced pressures. The GP-1010 series valves are controllable if the intersection point falls within the ranges indicated in the chart.

Cautions During Installation

• Provide space on the top and bottom of the valve so that the valve can be easily disassembled and inspected.
• Connect the safety valve outlet pipe to a safe location where steam discharge will not cause hazards.
• Be sure to install a strainer (around 80 mesh) at the inlet side of the product to prevent performance issues from debris.