Yoshitake GP-1000AS pilot-operated pressure reducing valve for steam applications. It offers all stainless steel construction (GP-1000AS), providing excellent corrosion resistance. The spherical main valve ensures great sealability, greatly reducing valve seat leakage, and the design complies with the SHASE-S106 standard for pressure reducing valves.

Features

• Improved corrosion resistance with all stainless steel construction (GP-1000AS).
• Spherical main valve offers great sealability and great reduction of valve seat leakage (compliant with ANSI Class IV).
• Compliant with SHASE-S106 Pressure Reducing Valves (by the Society of Heating, Air-Conditioning and Sanitary Engineers of Japan).

Specifications

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℃
Valve seat leakage	0.01% or less of rated flow
Body Material	Cast stainless steel
Valve, valve seat Material	Stainless steel
Piston, cylinder Material	Stainless steel
Connection	JIS 10K FF flanged

Dimensions and Weights

Nominal size	L	H1	H	Weight (kg)
15A	150	67	298	8.5
20A	155	67	298	9.0
25A	160	70	313	10.7
32A	190	85	336	15.0
40A	190	85	336	15.5
50A	220	96	360	21.0
65A	245	103	370	27.6
80A	290	125	417	39.0
100A	330	148	464	54.7
(Values are specific to the GP-1000AS all-stainless model).

Operation

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

The pressure-reducing valve reduces pressure by throttling the valve.

1. When mounted correctly, releasing the compression of adjusting spring closes the main valve and pilot valve. Slowly open the gate valve to allow high-pressure fluid to flow in.
2. Turning the adjusting screw clockwise compresses the spring, which flexes the diaphragm to open the pilot valve.
3. Inlet pressure via the pilot valve enters the upside of the piston. The pressure overrides the pressure on the downside of the main valve and the main valve spring load, opening the main valve.
4. Reduced pressure is led to the diaphragm chamber via the sensing port. The diaphragm balances the reduced pressure with the adjusting spring load, controlling the pilot valve travel.
5. The change in pilot valve travel changes the flow rate to the piston, controlling the main valve travel to maintain appropriate reduced pressure.

Nominal Size and Specifications Selection

Example: When selecting the nominal size of a pressure reducing valve whose inlet pressure (P1) is 0.6 MPa, reduced pressure (P2) is 0.4 MPa, and steam flow rate is 800 kg/h:

1. Find intersection point (A) of the inlet pressure 0.6 MPa and reduced pressure 0.4 MPa.
2. Trace down vertically to find intersection point (B) with the flow rate of 800 kg/h.
3. Since intersection point (B) lies between nominal sizes 40A and 50A, select the larger one, 50A. Note: Set the safety factor at 80 to 90%.

Find the intersection point of the inlet and reduced pressures. If the intersection point is within range (A), (B), or (C), the pressures are controllable (GP-1000 series).

Characteristics

• Shut-off pressure raise: 0.02 MPa or less
• Offset: 0.03 MPa or less (Setting pressure: 0.03~0.1 MPa) / 0.05 MPa or less (Setting pressure: 0.1~1.4 MPa)

Safety Valve Setting Pressure

Set pressure of pressure reducing valve (MPa)	Set pressure of safety valve (MPa)
0.1 or less	Set pressure + 0.05 or more
0.11 - 0.4	Set pressure + 0.08 or more
0.41 - 0.6	Set pressure + 0.1 or more
0.61 - 0.8	Set pressure + 0.12 or more
More than 0.8	Set pressure + 15%

Flow Rate Table (kg/h)

P1 (MPa)	P2 (MPa)	15A	20A	25A	32A	40A	50A	65A	80A	100A
1.0	0.05	92	212	369	600	831	1,478	2,310	3,326	5,913
1.0	0.1-0.4	132	303	528	858	1,188	2,112	3,300	4,752	8,448
0.5	0.5	127	292	508	826	1,145	2,035	3,180	4,580	8,142
0.6	0.6	117	269	468	761	1,053	1,873	2,927	4,215	7,494

(Excerpt of full flow rate table based on typical pressures. When inlet pressure is more than 0.7 MPa and reduction ratio is > 10:1, calculate the corrected Cv value multiplying the rated Cv value by the correction factor).

Installation and Maintenance

Installation Precautions

• Do not touch the product with bare hands directly during operation to prevent burns.
• Ensure piping is clean before connecting to remove any debris or scale.
• Install a strainer (around 80 mesh) at the inlet side.
• Install pressure gauges at both inlet and outlet sides for proper adjustment.
• Install a steam trap before the reducing valve to prevent condensate issues.
• Install bypass piping to allow maintenance.

Periodic Replacement Parts

• Pilot valve diaphragm: 2 years
• Piston ring: 3 years
• Inner ring: 3 years
• Pilot valve kit: 5 years
• Gaskets: 2 years (or whenever disassembled)
• Strainer: 5 years