Yoshitake GD-45 and GD-45P are compact and lightweight direct-acting pressure reducing valves designed for steam applications. They are applicable to inlet pressures of up to 2.0 MPa and feature a maximum pressure reduction ratio of 10:1. The valves utilize an external pressure type bellows for the pressure sensing part, ensuring excellent workability.

The GD-45 features a standard adjusting screw, while the GD-45P incorporates a Polyphenylene sulfide (PPS resin) handle, allowing for pressure adjustment without the use of any tools.

Features

1. Compact and lightweight.
2. Simple structure and easy maintenance.
3. Applicable to inlet pressure of up to 2.0 MPa.
4. A screen (60 mesh) is incorporated to protect the valve and valve seat from dirt.
5. Excellent workability accomplished by the external pressure type bellows of pressure sensing part.
6. Pressure adjustment is handle-operated without any tool (GD-45P).

Dimensions and Weights

GD-45

Nominal size	d	L (mm)	H1 (mm)	H (mm)	Weight (kg)
15A	Rc 1/2	111	47	216	3.2
20A	Rc 3/4	111	47	216	3.2
25A	Rc 1	111	47	216	3.2

GD-45P

Nominal size	d	L (mm)	H1 (mm)	H (mm)	Weight (kg)
15A	Rc 1/2	111	47	213	3.2
20A	Rc 3/4	111	47	213	3.2
25A	Rc 1	111	47	213	3.2

Chart for Selecting Nominal Sizes

Example: When selecting the nominal size of a pressure reducing valve whose inlet pressure (P1), reduced pressure (P2), and flow rate are 1.3 MPa, 0.6 MPa, and 200 kg/h, respectively, first find the intersection point of the inlet pressure of 1.3 MPa and the reduced pressure of 0.6 MPa. Trace down vertically from this intersection point to find the nominal size with a flow rate of 200 kg/h or over. In this case, the nominal size is 20A. Set the safety factor at 80 to 90%.

Operation and Construction

When the adjusting screw clockwise compresses the spring, the bellows are extended and the spindle opens the valve. When the valve opens, the steam flowing to the outlet side passes through the reduced pressure detection hole, and becomes an upwardly directed pressure under the bellows and balances the force of the spring. The degree of valve opening is adjusted by the balancing of inlet and reduced pressures, thereby stabilizing reduced pressure.

No.	Parts Name	No.	Parts Name
1	Body	8	Spindle
2	Spring Chamber	11	Bellows
3	Cap	14	Adjusting Spring
4	Valve Seat	16	Adjusting Screw
5	Valve	18	Bolts
6	Valve Spring	20	Handle (Only GD-45P)
7	Screen

Installation

Example of Piping

WARNING

In case installing safety valve as safety device at outlet side, joint relief pipe at outlet of safety valve and guide it to safety place where steam can relief out. Failure to do so may result in burns.

::: caution Installation Precautions

• Install a strainer (80 mesh) at the valve inlet side.
• Install a safety valve at the valve outlet sides as safety device for equipment.
• 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.
• When installing quick open and close valves, such as a solenoid valve, install it at inlet side as much as possible, and secure at least 3 m from the valve.
• When pressure reducing in two stages, secure at least 3 m between the valves.
• Provide the by-pass line.
• Set pressure of safety relief valve should be higher than the pressure reducing valve's pressure.
• Provide space on the top and bottom of the valve so that the valve can be easily disassembled and inspected. :::

Operating Procedure

WARNING

• Do not touch the valve directly with bare hands.
• Do not touch the handle directly with bare hands. Use protective leather gloves while operating the valve. (GD-45P)

::: caution

• Close the stop valves before and after the reducing valve, and remove all foreign matter and scales via the by-pass line before operation. And, open each stop valve slowly.
• When adjusting pressure, slowly turn the handle.
• Do not use tools to turn the handle. (GD-45P)
• Press and turn the handle. (GD-45P) The handle usually does not rotate due to the stopper.
• The rotation range of the handle is limited. Do not rotate it over the limit. (GD-45P) :::

Adjustment Procedure

GD-45:

1. Close the stop valve at inlet and outlet side, and blow off the fluid to remove foreign matter via the by-pass line. After blowing, close the by-pass line stop valve.
2. Slowly open the stop valve at the inlet side, and adjust the travel of the stop valve at the outlet side so that a little fluid flows.
3. Loosen the lock nut, and slowly turn the adjusting screw to achieve the desired pressure (clockwise to increase, counterclockwise to reduce) while observing the pressure gauge on the outlet side.
4. Slowly open the stop valve at the outlet, and readjust the desired pressure. After adjustment, tighten the lock nut.

GD-45P:

1. and 2. Same as GD-45.
2. Press and slowly turn the handle until the pressure is adjusted to the desired level checking the pressure gauge mounted on the outlet side. Turn the handle clockwise to increase, and counterclockwise to decrease the pressure.
3. Slowly open the stop valve at the outlet side, and make fine adjustments to the reduced pressure.

Maintenance and Troubleshooting

Problem	Cause	Solution
Pressure does not rise to the desired level.	1. Incorrect pressure is being used. 2. Nominal size is too small for these specifications. 3. Incorrect adjustment. 4. Strainer installed before pressure reducing valve is clogged. 5. Screen is clogged. 6. Pressure gauge malfunction.	1. Correct the pressure. 2. Replace with the correct nominal sized item. 3. Re-adjust according to the adjustment procedure. 4. Disassemble and clean. 5. Disassemble and clean. 6. Replace the pressure gauge.
Reduced pressure exceeds prescribed level.	1. Foreign matter is embedded in the valve and/or valve seat, or else scratches exist. 2. Reduced pressure sensing hole is clogged with foreign matter. 3. By-pass valve is leaking.	1. Disassemble and clean. If scratches exist, polish them away. 2. Disassemble and clean. 3. Repair or replace the valve.
Abnormal noise is heard.	1. Pressure reduction ratio is too large. 2. Drainage problem. 3. An abrupt open/close valve is located too close to the pressure reducing valve.	1. Use a two-stage reduction. 2. Install a trap. 3. Move distance as much as possible between the valves.

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.

Exploded Drawings

GD-45

GD-45P