Yoshitake GD-27GS is a direct-acting pressure reducing valve designed for air and other non-dangerous fluids. It features a JIS 10K FF flanged connection and a pressure balance structure that maintains a constant reduced pressure without being affected by inlet pressure fluctuations. The wetted parts are constructed from stainless steel for enhanced corrosion resistance, and it features a low-noise design.

Models in the 20A to 50A nominal size range incorporate a built-in 40 mesh strainer, while sizes 65A to 100A do not include a strainer. A pressure gauge connection port (JIS Rc 1/4 or R1/8) is provided.

Features

• Stainless steel is used for wetted parts.
• Reduced noise.
• Pressure balance structure can keep the reduced pressure at a constant level without being affected by inlet pressure.
• Maintenance and inspection can be conducted easily by disassembling simply from the upper side.
• Compact and lightweight, easy to handle on piping.
• Available with FKM (Fluorine rubber) for medium including oil.

Specifications

Specification	Value
Model	GD-27GS
Application	Air, Other non-dangerous fluids
Inlet pressure	1.0 MPa or less
Reduced pressure	(A) 0.05 - 0.35 MPa (B) 0.30 - 0.70 MPa
Minimum differential pressure	0.05 MPa
Maximum pressure reduction ratio	10 : 1
Application temperature	5 - 90 °C
Body material	Cast stainless steel
Valve seat material	Cast stainless steel / Stainless Steel
Valve disc material	EPDM
Diaphragm material	EPDM
Connection	JIS 10K FF flanged

WARNING

Please contact the manufacturer when using for gas containing oil. For medium including oil, use fluorine rubber for disc and diaphragm. If not, the disc and diaphragm may be broken.

Dimensions and Weights

Nominal size	L (mm)	H (mm)	H1 (mm)	Weight (kg)
20A	160	170	41	3.9
25A	160	170	41	4.8
32A	200	224	57	8.0
40A	200	224	57	8.3
50A	220	239.5	61	10.8
65A	220	329	77	20.6
80A	230	345	82	22.0
100A	270	412	94	34.5

Performance Characteristics

Flow Rate Characteristics

Offset

Pressure range	Reduced pressure range	Offset
A	0.05 - 0.35 MPa	0.05 MPa or less
B	0.30 - 0.70 MPa	0.10 MPa or less

Pressure Characteristics

This chart shows variation in reduced pressure when the inlet pressure of 0.6 MPa is changed between 0.15 MPa and 1.0 MPa while the reduced pressure is set at 0.1 MPa.

Internal Structure & Operation

The adjusting screw compresses the adjusting spring, pushes down on the diaphragm, and opens the disc that is directly connected to it. The fluid that entered from the primary side flows out from the upper part of the disk to the secondary side, and at the same time, acts directly on the diaphragm as the secondary side pressure.

Nominal Sizes Selection

Rated Cv Value

Nominal size	15A	20A	25A	32A	40A	50A	65A	80A	100A
Rated Cv value	2	2.3	3.5	6	7	11	21	26	38

Installation

Piping Example

The product can be installed either horizontally or vertically.

Installation Precautions

• Before installing the product in the piping, be sure to remove foreign substances and scale from the piping.
• Be sure to install a strainer at the inlet side of the product of nominal size 65A to 100A (40 mesh or more is recommended).
• Install a safety relief valve for equipment protection at the outlet side of the product.
• Be sure to install pressure gauges at the inlet and outlet sides of the product.
• If a quick operating valve such as a solenoid valve is installed, place it at a distance of at least 3 meters from the product.

Adjusting Procedure

1. Close the stop valves at the inlet and outlet sides of the reducing valve, and take adequate time to blow out fluid by using a bypass line.
2. Fully open the stop valve at the inlet side slowly, and open the stop valve at the outlet side so that a little fluid can flow through.
3. Remove the domed cap nut and turn the adjusting screw while watching the pressure gauge at the outlet side.
   • Turn the adjusting screw to the right (clockwise) to increase the reduced pressure.
   • Turn the adjusting screw to the left (counterclockwise) to decrease the reduced pressure.
4. Fully open the stop valve at the outlet side slowly.
5. After the adjustment is complete, tighten the domed cap nut.

Troubleshooting

Trouble	Cause	Remedy
Reduced pressure does not reach the desired value.	1. Working pressure is improper. 2. Nominal size is too small. 3. Pressure adjustment is improper. 4. Built-in strainer is clogged. 5. Pressure gauge is broken.	1. Correct the working pressure. 2. Replace with proper nominal size. 3. Readjust the pressure. 4. Clean the strainer. 5. Replace pressure gauge.
Abnormal pressure rises at the outlet side.	1. Foreign substances stuck between disc and valve seat, or scratch on them. 2. O-ring is damaged. 3. Diaphragm is damaged. 4. Leakage from the globe valve of bypass line.	1. Disassemble and remove foreign substances or replace parts. 2. Replace O-ring. 3. Replace diaphragm. 4. Repair or replace globe valve.
Abnormal sound	1. Nominal size is too large for the system. 2. Pressure reduction ratio is too large. 3. Quick operating valve is located near the product.	1. Replace with proper nominal size. 2. Reduce pressure in two stages. 3. Keep a distance between them as large as possible.

Maintenance

Clean the strainer regularly at least once or twice a year. Too much deposit of scales decreases the flow rate. Recommended replacement for consumable parts:

• Three years: Diaphragm, O-ring, Disc
• Five years: Other internal O-rings