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Actuator Systems RMG 670, RMG 671

General Description

Serving the Gas Industry - WORLDWIDE

670.00

edition 10/2000

Actuator Systems RMG 670, RMG 671 Application The actuators RMG 670 (K 16, K 18) and RMG 671 (K 17, K 19) are designed to operate safety devices (SSV).

They can be used as: • actuator of a safety shut-off valve (SSV, e.g. RMG 711, RMG 721, and RMG 731) Their function is to automatically close the main valve in order to shut off the gas flow in gas pressure regulating stations, as soon as the pressure to be controlled rises above or falls below the pre-set adjustable limits.

• measuring unit of a safety relief valve (SBV, e.g. RMG 850) To automatically open the valve, as soon as the pressure to be controlled reaches a pre-set overpressure limit. The highly sensitive diaphragm systems of these actuators offer the advantage of a high response accuracy across a large temperature range and the response pressure can be closely approached to the pressure to be controlled.

Advantages • • • •

high response accuracy low pressure differential between release pressure and the service pressure to be monitored easy maintenance and operation suitable for natural gas and all non-corrosive gaseous media

1. Technical data max. operating pressure pmax

100 bar

type

K 16, K 17 for response pressure ranges from 0,8 to 40 bar with diaphragm type measuring unit K 18, K 19 for response pressure ranges from 20 to 90 bar with metal-harmonica type measuring unit

for safety shut-off valves

RMG 670 / K 16, K 18 upper response pressure range Who = 0,8 bar to 90 bar RMG 671/ K 17, K 19 lower response pressure range Whu = 2 bar to 40 bar

for safety relief valves

RMG 670 / K16, K18 response pressure range Wh 0,8 bar to 90 bar

connections

screw connection without brazing acc. to DIN 2353 for pipe diameter measuring line vent line bleed line switching pressure line

ambient temperature range

-20 C to +70 C

materials

body parts internal parts o-rings diaphragms

weight

approx. 1,5 kg

2

12 mm 12 mm 12 mm 10 mm

aluminium alloy aluminium alloy, stainless steel rubber-like_plastic_material rubber-like_plastic_material

Actuator Systems RMG 670, RMG 671 2. Measurements actuator K 16 / K 17 connection for measuring line only for safety relief valve

actuator K18, K 19 connection for measuring line only for safety relief valve

measurements in mm type

A K16 / K17 26 for safety shut-off valve K18 / K19 60 K16 26 for safety relief valve K18 60

B 100 131 100 131

C

40 37

D(max) 195 340 195 340

E

F

G

G

60 60 60 60

75 85 75 85

50 60 50 60

20 18

J

38 38

3

Actuator Systems RMG 670, RMG 671 3. Construction The actuator consists of the measuring unit and the base plate. The double diaphragm system in the measuring unit has an integrated nozzle and baffle plate as amplifying valve. The measuring unit also incorporates the setpoint spring and the setpoint adjusting screw. The base plate incorporates a throttle valve and the connecting lines within the actuator.

The only difference in the principal designs of the actuators RMG 670 for safety shut-off release or safety relief action lies in the position of the throttle valve.

- safety shut-off operation: The pressure to be controlled is fed to the upper side of the highly sensitive double diaphragm system through a measuring impulse line and compared to the pressure adjusted by the set-point spring (force of the setpoint spring). In the normal service condition the amplifying valve is closed. The pipe system to the pressure converter and the pressure converter itself are de-pressurized.

If the service pressure in the line rises to the pre-set overpressure limit of the RMG 670 actuator (or falls to the underpressure limit of the actuator RMG 671), the the amplifying valve opens to let gas flow from the measuring line to the pressure converter. The resulting pressure build-up releases the tripping unit of the safety shut-off valve, and the SSV shuts off the gas flow in the mains.

If the faults causing the closing of the valve are found and eliminated, and if the pressure to be controlled has again fallen below the necessary re-engagement differential (RMG 671: risen above the re-engagement differential), the amplifying valve closes again. The pressure in the pressure converter is then quickly vented to the atmosphere via the throttle in the discharge line, and the safety shut-off main valve can be opened again.

actuator RMG 670 K16 (for overpressure release) breathing- / vent line

setpoint adjuster setpoint spring

throttle valve pressure converter amplifying valve connection for measuring line double diaphragm system

4

Actuator Systems RMG 670, RMG 671 actuator RMG 671 / K17 (for underpressure release) setpoint adjuster breathing- / vent line

setpoint spring

throttle valve

pressure converter

amplifying valve connection for measuring line double diaphragm system

actuator RMG 670 / K18 (for overpressure release) with metal-harmonica type measuring unit

setpoint adjuster breathing line

setpoint spring

throttle valve

pressure converter

double diaphragm system amplifying valve connection for measuring line metal-harmonica type measuring unit

5

Actuator Systems RMG 670, RMG 671 Safety Relief Valve Operation: The safety relief valve (i.e. RMG 850) opens as soon as the pressure to be monitored reaches the pre-set level, thus venting the surplus gas into the atmosphere. The safety relief valve consists of the main valve and the actuator RMG 670. A fine filter is placed as protection against dust or dirt in front of the actuator and the bleed.

The main valve RMG 850 controls the gas flow via the valve cone and the valve sleeve. The piston is fixed onto the valve sleeve. The upper and lower chamber of the piston are connected via the base plate of the actuator RMG 670. Thus the pressure at the piston is compensated, and the closing spring holds the valve sleeve in the CLOSED position.

The pressure within the system to be monitored is led via the measuring line to the lower side of the double diaphragm system in the actuator. The force of the pressure is then compared with the pre-set value of the setpoint spring.

Should the pressure to be monitored reach the pre-set value, then the nozzle within the double diaphragm system opens and thus vents the pressure from the lower side of the piston to the atmosphere. The prevailing service pressure on the top side presses the piston and the valve sleeve downward, and the surplus gas in the main pipe is released to the atmosphere.

If the line pressure then falls again below the pre-set value, the actuator valve closes, and the pressure underneath the piston increases again via the throttle to service pressure value. The pressure compensation at the piston enables the closing spring to shut the safety relief valve automatically.

For first pressurization in the line the start-up valve should be pressed to enable quick pressure compensation at the piston, thus keeping the main valve of the safety relief valve closed during pressure build-up.

safety relief valve RMG 850 with actuator RMG 670 / K16 vent line manual release (optional)

main valve valve cone

actuator RMG 670 / K16

vent line

valve sleeve

start-up valve

piston throttle closing spring filter

6

double diaphragm system

measuring line

Actuator Systems RMG 670, RMG 671 4. Type Description (example)

RMG 670

-

A

-

3 -

So

type RMG 670 RMG 671

RMG 670 RMG 671

version for safety shut-off valve safety relief valve actuator K16 K16 K16 / K17 K16 / K17 K16 / K17 K18*

A B

setpoint range in bar Who Whu 0.8 ... 1.5 1.0 ... 5.0 2.0 ... 10,0 5.0 ... 20.0 10.0 ... 40.0 20.0 ... 90.0

2.0 ... 10.0 5.0 ... 20.0 10.0 ... 40.0 -

special version (to be described in detail)

0 1 2 3 4 5 So

* with metal-harmonica type measuring unit

7

We supply you with products for gas pressure regulation: RMG REGEL + MESSTECHNIK GMBH Osterholzstrasse 45, D-34123 Kassel, Germany Telephone (++49) 561 5007-0 • Fax (++49) 561 5007-107 gas pressure regulators and safety devices

RMG-GASELAN Regel + Meßtechnik GmbH Julius-Pintsch-Ring 3, D-15517 Fürstenwalde, Germany Telephone (++49) 3361 356-60 • Fax (++49) 3361 356-836 gas pressure regulating equipment, displacement meters, complete stations

Bryan Donkin RMG Gas Controls Ltd. Enterprise Drive, Holmewood, Chesterfield S42 5UZ, England Telephone (++44) 1246 501-501 • Fax (++44) 1246 501-500 gas pressure regulating equipment, below ground gas control modules

Bryan Donkin RMG Co. of Canada Ltd. 50 Clarke Street South, Woodstock, Ontario N4S 7Y5, Canada Telephone (++1) 519 5398531 • Fax (++1) 519 5373339 domestic regulators and safety devices

The other RMG Companies: RMG Messtechnik GmbH Otto-Hahn-Strasse 5, D-35510 Butzbach, Germany Telephone (++49) 6033 897-0 • Fax (++49) 6033 897-130 turbine meters, vortex meters, correctors, flow computers, odorizers

Karl Wieser GmbH Anzinger Strasse 14, D-85560 Ebersberg, Germany Telephone (++49) 8092 2097-0 • Fax (++49) 8092 2097-10

works Beindersheim Heinrich-Lanz-Strasse 9, D-67259 Beindersheim/Pfalz, Germany Telephone (++49) 6233 3762-0 • Fax (++49) 6233 3762-40 data logging, monitor systems, danger alarm systems

WÄGA Wärme-Gastechnik GmbH Osterholzstrasse 45, D-34123 Kassel, Germany Telephone (++49) 561 5007-0 • Fax (++49) 561 5007-207 design and assembly of gas pressure regulating and metering stations

The RMG Group of Companies on the internet: http://www.rmg.de

Serving the Gas Industry - WORLDWIDE

We reserve the right for technical changes