Yoshitake GDK-2000 is a direct acting pressure reducing valve designed for steam applications. It features a simple but robust structure with fewer moving parts. The spherical main valve offers great sealability, providing a significant reduction of valve seat leakage compliant with ANSI Class IV. A large-size diaphragm ensures a high Cv value and distinguished controllability against load fluctuations. Furthermore, its remote operation capability makes pressure adjustment easy and provides a wide pressure setting range.

Specifications

Specification	Value
Application	Steam
Reduced pressure sensing method	External sensing
Inlet pressure	0.1-2.0 MPa / 0.1-1.0 MPa
Reduced pressure	0.05-1.4 MPa / 0.05-0.9 MPa (90% or less of inlet pressure)
Operation air pressure	Refer to the loading air pressure-set pressure chart
Minimum differential pressure	0.05 MPa
Maximum pressure reduction ratio	10:1
Maximum temperature	220℃
Valve seat leakage	0.01% or less of rated flow
Material (Body)	Ductile cast iron
Material (Valve)	Stainless steel
Material (Valve seat)	Stainless steel
Material (Diaphragm)	Stainless steel
Reduced pressure sensing pipe	Copper pipe φ 8-2 m
Connection	JIS Rc screwed, JIS 20K RF flanged, JIS 10K FF flanged

INFO

External sensing is standard. 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. Available with ASME or EN flanged.

Dimensions and Weights

Screwed Type

Nominal size	d	L	H1	H	A	Weight (kg)
15A	Rc 1/2	150	74	244	200	12.4
20A	Rc 3/4	150	74	244	200	12.4
25A	Rc 1	160	76	251	226	16.4
32A	Rc 1-1/4	180	90	282	226	19.9
40A	Rc 1-1/2	180	90	282	226	19.9
50A	Rc 2	230	103	319	276	30.5

INFO

Available with NPT connection.

Flanged Type

Nominal size	L	H1	H	A	Weight (kg)
15A	146 (142)	74	244	200	13.9 (13.7)
20A	146 (142)	74	244	200	14.4 (14.2)
25A	156 (152)	76	251	226	19.2 (18.8)
32A	176 (172)	90	282	226	22.4 (22.0)
40A	196 (192)	90	282	226	22.9 (22.5)
50A	222 (218)	103	319	276	33.5 (33.5)
65A	282 (278)	122	373	352	61.8 (61.5)
80A	302 (294)	135	399	352	69.1 (66.9)

INFO

The values in parentheses are the dimensions and weights of JIS 10K FF flanged. Please contact us about other specifications.

Specifications Selection

Please 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. When reducing pressure in two stages, maximize the distance between the valves (at least 3 m).

Nominal Sizes Selection

When selecting a nominal size, set the flow rate at 80 to 90% of the rated flow rate, allowing for the pressure loss and heat loss of the stop valve, strainer, etc. to be used before or after the pressure reducing valve. To enable the pressure reducing valve to show a maximum flow characteristic, do not select a small piping diameter, as a countermeasure against the effect of piping resistance.

When selecting the nominal size of a pressure reducing valve whose inlet pressure (P1), reduced pressure (P2), and flow rate are 0.6 MPa, 0.4 MPa, and 600 kg/h, respectively, first find intersection point (a) of the inlet pressure of 0.6 MPa and the reduced pressure of 0.4 MPa. Trace down vertically from this intersection point to find intersection point (b) with the flow rate of 600 kg/h. Since intersection point (b) lies between nominal sizes 20A and 25A, select the larger one, 25A. Set the safety factor at 80 to 90%.

Characteristic Charts

This chart shows variation in reduced pressure when the inlet pressure of 1.75 MPa is changed between 0.2 MPa and 2.0 MPa while the reduced pressure is set at 0.14 MPa.

Loading Air Pressure-set Pressure Chart

Basically, the set pressure to the loading air pressure is as shown in the chart above. The set pressure is slightly different depending on the working conditions. For the actual use, adjust loading air pressure suitable for the necessary set pressure.

This chart shows variation in reduced pressure when the inlet pressure of 1.4 MPa is changed between 0.2 MPa and 1.4 MPa while the reduced pressure is set at 0.14 MPa.

How to read the chart (GDK-2000)

When the nominal size is 25A, the inlet pressure (P1) is 1.0 MPa, and the reduced pressure (P2) is 0.2 MPa, the loading air pressure is calculated as follows: Trace up vertically from the differential pressure (∆P) before and after the pressure reducing valve (1.0 MPa – 0.2 MPa = 0.8 MPa) to find intersection point (a) with the nominal size of 25A. Calculate ΔPa [loading air pressure (Pa) – set pressure (P2)] = 0.037 MPa by horizontally tracing to the left from intersection point (a). Thus, the loading air pressure is: (Pa) = ∆Pa + P2 = 0.037 + 0.2 = 0.237 MPa.