Steam Pressure Reducing Valves - Series RE |
Pressure reducing Valves (PRV) are designed for regulating downstream pressure and maintaining it within certain acceptable limits.
Ideally, a PRV should provide constant downstream pressure while delivering the required flow, i.e. the PRV automatically adjusts the steam flow to meet the
downstream system demand.
MIYAWAKI's pressure reducing valves are designed only for steam.
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| Types
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MIYAWAKI is manufacturing two types of PRV:
- Direct acting pressure reducing valves RE1, REC1 and RE2.
- Pilot operated pressure reducing valves RE3 and RE10N.
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| Model Name
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Available
Sizes
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Available
Connections
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Max.Operating
Pressure
MPa (psig)
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Max.Operating
Temperature
AC (AF)
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Secondary
Pressure
Range
MPa (psig)
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Body and
Cover Material
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Download
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| DIRECT ACTING PRV
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| RE1
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1/2" – 1"
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Screwed Rc & NPT
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1,6 (230)
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204 (399)
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0,05 – 1,0
(7 – 145)
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Brass
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(548 KB)
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| RE2
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3/8"
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1,0 (145)
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184 (363)
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0,1 – 0,5
(14 – 72)
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| REC1
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1/2"– 1"
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Screwed Rc & NPT
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1,6 (230)
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220 (428)
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0,03 – 1,0
(4.4 – 145)
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Stainless
Steel
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(559 KB)
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| REC1F
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DN15-DN25
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Flanged JIS, ANSI, DIN
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1,6 (230)
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220 (428)
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0,03 – 1,0
(4.4 – 145)
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| PILOT OPERATED PRV
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| RE3
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1/2" – 2"
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Screwed Rc & NPT
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1,6 (230)
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220 (428)
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0,03 – 1,2
(4.4 – 174)
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Brass
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(925 KB)
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| RE10N
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DN15 - DN50
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Flanged JIS, ANSI, DIN
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1,6 (230)
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220 (428)
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0,03 – 1,2
(4.4 – 174)
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Ductile
Cast Iron
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(502 KB)
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| Operating principle - General
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Direct Acting PRV
The direct acting PRV has 3 essential elements:
A Main Valve Unit
B Pressure Measuring Element (Bellows)
C Adjust Spring
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Pilot Operated PRV
The pilot operated PRV has 4 essential elements:
A Main Valve Unit
B Pilot Valve (same structure as the direct-acting PRV)
C Adjusting Unit (piston and cylinder liner)
D Signal Line
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Changes in downstream pressure are sensed by the bellows, which expands or contracts depending on the pressure change.
The movement of the bellows will be directly transferred to the spring, which will open or close the main valve, thus keeping the downstream pressure at a
certain level.
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Changes in downstream pressure are sensed by the pilot valve mechanism (bellows connected with a pilot valve unit)
through a signal line D, which connects the pilot valve regulator with the secondary pressure side.
Movement of the bellows will open or close the pilot valve, regulating the amount of steam influencing the movement of the piston, which will close or
open the main valve, thus keeping downstream pressure on a stable level.
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| Operating principle - Pilot Operated PRV RE3 & RE10N
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 Inlet Steam Pressure
 Secondary Steam Pressure
 Adjusting Steam Pressure
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Before adjusting the secondary pressure the green handle must be turned clockwise to relea se the adjust spring No.15 until the
handle moves freely. In this position the main valve (4) is closed by the force of the spring No. 6 and the pilot valve (11) is closed by the force of the
spring No. 13. When steam enters the valve, part of the steam enters the pilot chamber (X) through the orifice (Y).
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To adjust the secondary pressure the handle must be turned counterclockwise. As a result, the adjust spring (15) will be
pressed into the bellows (14). The bellows will expand and the pilot valve shaft (47) will open the pilot valve (11). The steam, which has entered
the pilot chamber (X) will flow through the pilot valve unit into the chamber above the piston (7). Due to the steam pressure the piston (7) will move downwards
and open the main valve (4). Steam will flow towards the secondary side.
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Part of the steam, which flows to the secondary side will enter the pressure sensing chamber (Z) through the pressure signal line (D).
Due to the pressure influence, the bellows (14) will contract. Depending on the secondary pressure value the force exerted by the bellows and the force exerted by the
adjust spring (15) will be balanced and the opening degree of the pilot valve (11) will be adjusted, thus regulating the amount of steam flowing through the pilot
valve to the piston. Consequently, the opening degree of the main valve (4) will be also adjusted to regulate the steam flow in the direction of the secondary
side maintaining a stable steam flow and steam pressure on the secondary side.
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