Yoshitake GD-43G-20 direct type pressure reducing valve is designed for use with air, carbon dioxide gas, nitrogen gas, and steam for washing or sterilization. The pressure balance structure maintains the reduced pressure at a constant level without being affected by the inlet pressure, making it highly reliable for precision applications.

Features

• Space saving and resource saving are achieved. Used materials are shown on the body and lower cap, thus separate collection of parts for resource recycling is easy.
• Stainless steel (SCS14A and SUS316) is used for wetted parts, improving corrosion resistance.
• PTFE covers the diaphragm contact surface to fluid, making the diaphragm less liable to deteriorate and highly durable.
• Special fluorine-contained rubber parts are resistant to corrosion.
• Pressure balance structure can keep the reduced pressure at a constant level without being affected by inlet pressure.
• Enclosed structure prevents fluid from escaping outside the valve even if the diaphragm is damaged.
• Can be applied to piping washing, system washing, sterilization washing, and steam for sterilization.
• Horizontal or vertical installation is available.

Specifications

Parameter	Value
Application	Air, Carbon dioxide gas, Nitrogen gas, Steam for washing or sterilization
Inlet pressure	0.07-2.0 MPa (0.2 MPa or less for steam for washing or sterilization)
Reduced pressure	(A) Yellow spring: 0.02-0.1 MPa (B) Red spring: 0.1-0.25 MPa (C) Black spring: 0.25-0.5 MPa
Minimum differential pressure	0.05 MPa
Maximum pressure reduction ratio	20:1
Fluid temperature	5-90°C
Body Material	Cast Stainless steel (SCS14A)
Valve disc Material	Special synthetic rubber (special FKM)
Diaphragm Material	Heat-resistant synthetic rubber and PTFE
Connection	JIS 20K RF flanged

Temperature Limit for Steam

If using for washing steam or sterilization steam, be sure that the maximum temperature is 130°C and avoid continuous use for more than 30 minutes. Allow an interval of at least four hours between steam flows.

Dimensions and Weights

Nominal Size	Flange (JIS 20K RF) D	C	g	t	f	n-h	Weight (kg)
20A	100 mm	75 mm	56 mm	16 (14) mm	1 mm	4-15	3.0 (2.9) kg

(Note: The values in parentheses are the parameters of the GD-43G-10 model).

Performance Charts

Specifications Selection Chart

Flow Characteristic Chart

Offset Pressure:

Set pressure	Offset pressure
0.2 MPa or less	Within 0.05 MPa
More than 0.2 MPa	Within 0.08 MPa

Pressure Characteristic Chart

This chart shows the change in the reduced pressure when the inlet pressure is changed in the range of 0.25 to 2.0 MPa whereas the reduced pressure is set at 0.20 MPa.

Nominal Sizes Selection Chart (For Air)

Installation and Operation

Strainer Recommendation

Be sure to install a strainer at the inlet side of the pressure reducing valve. Ingress of foreign substances or scale into the pressure reducing valve leads to malfunction of the product. It is recommended to use a strainer of 60 mesh or more.

Safety Valve Requirement

When installing a safety valve at the outlet side of the pressure reducing valve, connect a blow-off pipe to lead the possible discharged fluid to a safe location. Without a safety valve, an abnormal condition cannot be recognized and may damage the equipment.

1. Piping Distances: When installing a quick opening/closing device like a solenoid valve, or employing two-stage pressure reduction, keep a distance of at least 3 meters from the pressure reducing valve to avoid malfunctioning and shortened life.
2. Piping Orientation: The valve can be installed horizontally or vertically. Make sure the arrow on the valve body coincides with the fluid direction.
3. Flushing: Before connecting the pressure reducing valve to the piping, completely remove foreign materials by using a bypass pipe.

Maintenance and Troubleshooting

Periodic check and replacement of expendable parts are recommended to maintain performance. Under normal usage, the diaphragm set, disc, and O-rings generally require replacement every 3 years.

Symptom	Possible Cause	Corrective Action
Reduced pressure is higher than set pressure	Damaged diaphragm, pinched foreign material between valving disc and seat, or poor seal of valve stem O-ring.	Replace the diaphragm unit, clean the assembly, or replace the damaged O-ring.
Reduced pressure is lower than desired / Fluid fails to flow	Valve stem O-ring is locked or valving element P and valve seat are locked.	Replace the valve stem O-ring or clean the disc and valve seat section.
Exterior Leakage	Loose cross recessed pan head screw, loose cap, or broken O-ring for cap.	Retighten screws/cap, or replace the broken O-ring with a new one.