Yoshitake GD-27G is a direct type pressure reducing valve designed for air and other non-dangerous fluids. It features a bronze body and EPDM diaphragm, offering a maximum pressure reduction ratio of 10:1. The pressure balance structure maintains reduced pressure at a constant level without being affected by inlet pressure fluctuations. The wetted parts use corrosion-resistant materials, and the valve provides reduced noise operation.

The GD-27G utilizes a JIS 10K FF flanged connection (available in nominal sizes 25A to 100A), while the related GD-26G uses a JIS Rc screwed connection. Maintenance and inspection can be performed easily by disassembling the unit from the upper side.

Features

• Corrosion-resistant materials are 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.

Specifications

Model	GD-27G	GD-26G
Application	Air, Other non-dangerous fluids *	Air, Other non-dangerous fluids *
Inlet pressure	1.0 MPa or less	1.0 MPa or less
Reduced pressure	(A) 0.05-0.35 MPa (B) 0.3-0.7 MPa	(A) 0.05-0.35 MPa (B) 0.3-0.7 MPa
Fluid temperature	5-90℃	5-90℃
Minimum differential pressure	0.05 MPa	0.05 MPa
Maximum pressure reduction ratio	10:1	10:1
Body material	Bronze	Bronze
Valve seat material	Bronze	Bronze
Valve disc material	EPDM	EPDM
Diaphragm material	EPDM	EPDM
Connection	JIS 10K FF flanged	JIS Rc screwed

Notes

• • Please contact the manufacturer when using for gas containing oil. For medium including oil, fluorine rubber must be used for the disc and diaphragm to prevent damage.
• 65A to 100A models do not include a strainer. A strainer (40 mesh) is incorporated in 15A to 50A models.
• The pressure gauge connection port is JIS Rc 1/8 (maximum temperature 45°C).

Dimensions and Weights

GD-27G

Nominal size	L (mm)	H (mm)	H1 (mm)	Weight (kg)
25A	160	170	41	5.1
32A	200	224	57	7.5
40A	200	224	57	7.7
50A	220	239.5	61	10.9
65A	220	329	77	20.0
80A	230	345	82	22.0
100A	270	412	94	33.0

Performance Charts

Pressure Characteristic Chart

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.

Flow Characteristic Chart

Nominal size	Pressure range	Offset pressure
15-100A	(A) 0.05-0.35 MPa	Within 0.05 MPa
15-100A	(B) 0.3-0.7 MPa	Within 0.10 MPa

Nominal Sizes Selection Chart

Selection Example

When selecting the nominal size of a pressure reducing valve whose inlet pressure (P1), reduced pressure (P2), and flow rate are 0.3 MPa, 0.2 MPa, and 200 m³/h (standard condition), respectively:

1. Find intersection point (a) of the inlet pressure (P1) of 0.3 MPa and the reduced pressure (P2) of 0.2 MPa.
2. Trace down vertically from this intersection point to find intersection point (b) with the flow rate of 200 m³/h (standard condition).
3. Since intersection point (b) lies between nominal sizes 25A and 32A, select the larger one, 32A.

• Set the safety factor at 80 to 90%.

Operation Principle

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.

When the sluice valve on the secondary side is closed, the pressure applied to the diaphragm increases, overcomes the load of the adjustment spring, and the disc closes. Gradually opening the sluice valve on the secondary side reduces the pressure applied to the diaphragm and opens the disc. The fluid flowing out to the secondary side acts on the diaphragm as the secondary side pressure, balances with the load of the adjustment spring, adjusts the valve opening, and keeps the secondary side pressure constant.

Installation Guidelines

Piping Example

Installation Precautions

• When installing a safety relief valve for equipment protection at the outlet side, connect a blow-off pipe to the outlet side of the safety relief valve, and lead it to a safe place.
• 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 recommended).
• Install a safety relief valve for equipment protection at the outlet side.
• Be sure to install pressure gauges at the inlet and outlet sides.
• 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.
• For two-stage pressure reduction, keep a distance of at least 3 meters between each product.