Yoshitake GPK-2003 is a pilot-operated, remote-controlled pressure reducing valve designed for steam applications. It features a spherical main valve that offers excellent sealability and significantly reduces valve seat leakage (compliant with ANSI Class IV). The remote control capability makes pressure adjustment easy and provides a wide pressure setting range. It is superior to piston-type valves in capacity and performance, effectively controlling inlet pressure and flow rate fluctuations. The GPK-2001 model is also available, and the choice between GPK-2001 and GPK-2003 depends on the loading air pressure.

Features

• Superior to piston type valve in capacity and performance. Very effective in controlling inlet pressure and flow rate fluctuations.
• Spherical main valve offers great sealability and great reduction of valve seat leakage (compliant with ANSI Class IV).
• Remote control makes pressure adjustment easy, and the pressure setting is wide.
• The GPK-2001 and GPK-2003 can be selected according to the loading air pressure.

Specifications

Model	GPK-2001	GPK-2003
Application	Steam	Steam
Reduced pressure sensing method	External sensing *	External sensing *
Inlet pressure (JIS Rc, JIS 20K RF)	0.1-2.0 MPa	0.25-2.0 MPa
Inlet pressure (JIS 10K FF)	0.1-1.0 MPa	0.25-1.0 MPa
Reduced pressure (JIS Rc, JIS 20K)	0.05-0.9 MPa	0.2-1.4 MPa
Reduced pressure (JIS 10K)	0.05-0.85 MPa	0.2-0.85 MPa
Minimum differential pressure	0.05 MPa	0.05 MPa
Maximum pressure reduction ratio	20:1	10:1
Maximum temperature	220°C	220°C
Valve seat leakage	0.01% or less of rated flow	0.01% or less of rated flow
Body Material	Ductile cast iron	Ductile cast iron
Main valve / seat	Stainless steel	Stainless steel
Pilot valve / seat	Stainless steel	Stainless steel
Diaphragm	Stainless steel	Stainless steel
Connection	JIS Rc screwed, JIS 20K RF and 10K FF flanged	JIS Rc screwed, JIS 20K RF and 10K FF flanged

• External sensing is standard. Available with internal sensing type in different specifications.

Dimensions and Weights

Screwed Type

Nominal size	d	L	H1	H	A	Weight (kg) GPK-2001	Weight (kg) GPK-2003
15A	Rc 1/2	150	170	335 / 353	200	14.0	17.5
20A	Rc 3/4	150	170	335 / 353	200	14.0	17.5
25A	Rc 1	160	175	341 / 359	226	18.5	22.0
32A	Rc 1-1/4	180	192	371 / 389	226	21.5	25.0
40A	Rc 1-1/2	180	192	371 / 389	226	21.5	25.0
50A	Rc 2	230	216	435 / 453	276	33.0	36.5

Flanged Type (JIS 20K RF)

Nominal size	L	H1	H (GPK-2001/2003)	A	Weight (kg) GPK-2001	Weight (kg) GPK-2003
15A	146	170	335 / 353	200	15.5	19.0
20A	146	170	335 / 353	200	16.0	19.5
25A	156	175	341 / 359	226	21.0	24.5
32A	176	192	371 / 389	226	24.0	27.5
40A	196	192	371 / 389	226	24.5	28.0
50A	222	216	435 / 453	276	36.0	39.5
65A	282	251	489 / 507	352	64.5	68.0
80A	302	264	512 / 530	352	71.5	75.0
100A	342	321	595 / 613	401	111.0	114.5

Operation

The pressure reducing valve reduces pressure by throttling the valve. The valve is composed of the main valve, main valve seat, a pressure adjusting air chamber, and the main diaphragm, pilot diaphragm, and pilot valve for pressure sensing and activation.

1. When the pressure reducing valve is mounted correctly, the main valve and pilot valve should be closed by main valve spring and pilot valve spring when air pressure is no-pressure.
2. Introducing air pressure into air chamber flexes pilot diaphragm to open the pilot valve. The fluid passing through pilot valve and pilot valve seat enters the main diaphragm chamber.
3. When the flow rate at the pilot valve exceeds the flow rate at the orifice, operating pressure in the main diaphragm chamber raised and overrides the pressure on the upside of the main valve and the load of main valve spring to open the main valve.
4. Reduced pressure is led to the pilot diaphragm chamber via the sensing pipe and reduced pressure sensing port. The pilot diaphragm receives the reduced pressure to be balanced with the air pressure.

Nominal Size Selection

Specifications Selection Chart

Refer to the selection chart to select the most appropriate pressure reducing valve. Find the point of intersection of inlet pressure (P1) and reduced pressure (P2). When the point of intersection is within range (A), reduce pressure in two stages. When within range (B), controllable range. When within range (C), maximum performance cannot be obtained.

Safety Valve Setting Pressure Chart

Determine the reduced pressure of pressure reducing valve. Find the intersection point (A) with the chart curve. Next, find point (B) by proceeds horizontally from point (A) to the left until the ‘Setting pressure of safety valve’ axis. The setting pressure of the safety valve should be higher than the pressure of the point (B).

Characteristic Charts

Nominal Size Selection Chart

Nominal Size Selection Calculation Formula

An appropriate nominal size can be calculated by obtaining Cv value for the operating conditions in question.

Rated Cv value table (External sensing)

Nominal size	15A	20A	25A	32A	40A	50A	65A	80A	100A
Cv value	5.0	7.2	10.9	14.3	18.8	32	54	70	108

Installation

WARNING

Since the product is heavy, securely support it using lifting devices or the like when installing. Failure to follow this notice may cause falling accident of the product, resulting in bodily injury.

TIP

• Install a strainer (80 mesh) at the pressure reducing valve inlet side.
• Install a safety valve for equipment protection at the outlet side of the product.
• Install a pressure gauge at both the inlet and outlet sides of the valve.
• Install a steam trap to the inlet sides of the valve to prevent drainage problems.
• Install a bypass pipe around the pressure reducing valve.

Installing Accessories

When installing the pressure reducing valve, be sure to connect the provided sensing pipe and joint. Unless the sensing pipe is connected, the valve will not operate. Further, steam may blow off, resulting burns.

Maintenance and Troubleshooting

Troubleshooting

Problem	Cause	Solution
Pressure does not reach the desired value.	Incorrect pressure is being used. Insufficient operating air pressure. Screen is clogged. Main diaphragm is damaged.	Correct the pressure. Increase the operating air pressure. Disassemble and clean the screen. Replace the main diaphragm.
Reduced pressure raises above than the specified value.	Operating air pressure too high. Foreign matter exists between main valve and main valve seat.	Decrease the operating air pressure. Disassemble and remove the foreign matter.
Abnormal noise is heard.	Orifice of tee is clogged. Nominal size is too large for the specifications. Pressure reducing ratio is too large.	Remove the tee and clean it. Change the nominal size appropriately. Reduce pressure in two stages.

WARNING

Completely discharge internal pressure from the valves, lines, and equipment, and cool the valve down to a level where you can touch it with bare hands before disassembly and inspection.