Fushiman B260 type back pressure valve for steam

Model	Nominal diameter	Primary measurement pressure range	Maximum operating temperature	Body Material	Connection
B260	15–80	0.07 to 1.0 MPa	220°C	FC, FCD, SCPH	Flanges

Compact, lightweight, and high performance.
Designed for continuous discharge.
Large capacity.

Specifications and Materials

Fluid	Primary Side Set Pressure Range (MPa)	Maximum Operating Temperature (°C)	Main Component Materials					Pipe Connection
Fluid	Primary Side Set Pressure Range (MPa)	Maximum Operating Temperature (°C)	Valve Body & Cover	Main Body & Main Valve Seat	Piston & Cylinder	Pilot Valve Body & Pilot Valve Seat	Diaphragm	Pipe Connection
Steam	0.07～0.2	220	Cast Iron (¹)	Stainless Steel	Stainless Steel	Stainless Steel	Stainless Steel	Flange JIS 10K Full Face
	0.1～0.8
	0.5～1.0

Note (¹): The valve body for nominal diameters 15 to 40 is made of ductile cast iron.
Remarks:

Valve bodies made of cast steel or stainless steel castings are also available.
ASME Class 150 products are also available.

Performance

Minimum Set Differential Pressure			10% of Primary Side Pressure (Minimum 0.07 MPa)
Offset	Set Pressure MPa	0.07～0.2, 0.1～0.8	≤ 0.03 MPa
		0.5～1.0 MPa	≤ 0.05 MPa
Shut-off Pressure Drop	Set Pressure MPa	0.07～0.2	≤ 0.02 MPa
		0.1～0.8, 0.5～1.0	≤ 0.04 MPa
Minimum Adjustable Flow Rate			≤ 5% of Rated Flow Rate
Valve Seat Leakage			≤ 0.05% of Rated Flow Rate

Cv Value

Nominal Diameter (mm)	15	20	25	32	40	50	65	80
Cv Value	1.1	2.5	4.5	7	10.1	18	28.1	40.5

Structure and Dimensions

Dimensions and Weight

Nominal Diameter (mm)	L (mm)	H₁ (mm)	H₂ (mm)	K (mm)	Weight (kg)
15	145	81	171	115	8
20	150	76	176	115	8.5
25	160	73	178	115	10
32	175	77	188	115	12
40	190	85	198	111	14
50	210	95	212	111	18
65	235	111	231	111	26
80	265	123	248	111	32

Remarks:

K indicates the dimension when the adjustment screw is free.
Nominal diameters up to 150 can be manufactured. The dimensions and weight are similar to the P260 pressure reducer (see page 6 for reference).

Nominal Diameter Selection

Please select the appropriate nominal diameter using the nominal diameter selection chart.
If the selected diameter is too small, the required flow rate may not be achieved.
If it is too large, issues such as hunting or instability may occur, leading to poor performance.

When the set pressure and outlet pressure remain constant within a certain range,
choose a nominal diameter where the difference between the minimum possible set differential pressure and the outlet pressure allows for stable operation.

Additionally, the minimum required flow rate should not be less than 50% of the selected nominal diameter’s rated flow rate (maximum flow rate at maximum differential pressure).

Example of Use:

Saturated Steam

Set Pressure: 0.48 MPa
Outlet Pressure: 0.25 MPa
Flow Rate: 700 kg/h

To determine the appropriate nominal diameter:

Locate the intersection of 0.48 MPa set pressure and 0.25 MPa outlet pressure on the selection chart.
Identify the intersection with the 700 kg/h flow rate line.
If the intersection falls between nominal diameters 40 and 50, select the larger diameter for stable operation.
Therefore, the appropriate selection is nominal diameter 50.

Remarks:
For superheated steam, refer to the selection chart usage example on page 8.