degF (degC) Psig (Barg) Main valve seat
St St filled PTFE -50/500 (-46/+260) Upto 1480 (102)
PEEK -85/500 (-65/+260) Over 1480 (102)
Viton -4/400 (-20/+205) Upto 1480 (102)
Buna-N -50/248 (-46/+120) Upto 1480 (102)
Polyurethane -65/300 (-54/+150) 400/1480 (27.6/102) Main valve seat (NACE)
PEEK -85/500 (-65/+260) Over 1480 (102)
Viton -4/400 (-20/+205) Upto 1480 (102)
Polyurethane -65/300 (-54/+150) 400/1480 (27.6/102) Gaskets
Carbon Fibre -50/500 (-46/+260) All pressures
PILOT VALVE - MATERIALS Material Temperature
degF (degC) Body St St 316 All Bonnet St St 316 All Spring St St 316 All Trim St St 316 All Pilot seat and seals
Buna-N -50/248 (-46/+120) Viton -4/400 (-20/+205) EPR -65/300 (-54/+150) EPDM -50/400 (-46/+205) Aflas -20/400 (-29/+205) Heating or cooling coils required above 400degF (205degC) and below
BODY MATERIAL CARBON STEEL STAINLESS STEEL Item Description † -29 to +260 ºC -46 to +260 ºC -46 to +260 ºC
1 Body SA 216 WCB SA 352 LCB SA 351 CF8M
2 Nozzle St. St. 316 St. St. 316 St. St. 316
3 Guide St. St. 17/4 St. St. 17/4 St. St. 17/4
4 Disc holder St. St. 316 St. St. 316 St. St. 316
5 Disc insert Viton * Viton * Viton *
6 Piston St. St. 316 St. St. 316 St. St. 316
7 Locknut St. St. 316 St. St. 316 St. St. 316
8 Lift stop St. St. 316 St. St. 316 St. St. 316
9 Cover St. St. 316 St. St.316 St. St. 316
10 Retaining plate St. St. 316 St. St. 316 St. St. 316
11 Disc holder seal Viton * Viton * Viton *
12 Piston seal Viton * Viton * Viton *
13&25 Guide rings Carbon/PTFE Carbon/PTFE Carbon/PTFE
14 Body stud A193/B7 A193/B8T A193/B8T
15 Body nut A194/2H A194/8T A194/8T
16 Lock ring St. St. 316 St. St. 316 St. St. 316
19 Spring St. St. 316 St. St. 316 St. St. 316
20 Body gasket Carbon fibre Carbon fibre Carbon fibre *
21 Guide seal Viton * Viton * Viton *
22 Nozzle seal Viton * Viton * Viton *
23 Retaining plate screw Viton * Viton * Viton*
24 Counter sunk screw St. St. 316 St. St. 316 St. St. 316
27 Fittings St. St. 316 St. St. 316 St. St. 316
32 Tubes St. St. 316 St. St. 316 St. St. 316
42 Drain plug HTS HOLO-KROME HTS HOLO-KROME ASTM A479-316L
Note:
*Soft goods materials listed above are standard. For a full listing to cover the temperature ranges of the body materials listed above, it is necessary to refer to the seals, gaskets, selection table on the previous page.
†Maximum temperature is limited by the seal material.
Back Flow Preventer
Exterior Supply Filter
Remote pressure sensing
Many codes and standards restrict the inlet pipework pressure loss to 3% of the safety valve set pressure. There are occasions however, when the pipework loss is greater than this. In these instances the safety valve should always be connected for remote sensing. The valve is normally supplied with integral sensing; this means that the pilot senses pressure at the main valve nozzle entry. Under conditions of excessive system pressure loss, the valve, under flowing conditions, may cycle open and closed. This is due to the pilot sensing a reduced (artificial)
Remote Pressure Sensing
In order to overcome this problem the valve should be sensed remotely. The pilot in this case should have its inlet connected directly to the pressure source where the system pressure is stable and not flowing. The main valve nozzle will not contain a sensing tapping in this case.
Excessive system pressure losses will also reduce the flow rate through the valve. This will be in proportion to the absolute system pressure and must be taken into account when sizing the valve.
Remote sensing will ensure that the pilot operated safety valve operates without cycling or chatter Back flow preventer
High back pressures may exist in the outlet for various reasons such as common disposal systems. If this back pressure can be more than the inlet system operating pressure, the main valve could lift allowing reverse flow from the outlet to inlet system.
A back flow preventer is a two-way check valve, which is fitted into the dome line. It allows the highest pressure from either the inlet system or outlet system to enter the dome, ensuring the main valve remains closed and prevents the possibility of reverse flow.
All modulating pilots (Types 4 + 8) should be fitted with a back flow preventer.
A back flow preventer should always be fitted if a vacuum can exist in the inlet pipework.
When using back flow preventers with back pressure above 50% of the set pressure, the actual service conditions must be reviewed by the factory.
External supply filter
This unit protects the pilot valve when working under
“dirty” flow stream conditions. All Safeset pilots are fitted with integral filters as standard; however, under conditions where there is likely to be large amounts of particulate matter in the flow stream, a supply filter should be used. This unit is fitted into the pilot sensing pipe, upstream of the pilot, and is suitable for gas and liquid duty. It is removed easily for maintenance.
Sense Line (Max 100ft/30m including one 90° bend. Min inside diameter 0.254"/6mm)
Field Test Connector
Remote Pressure Sensing
Heating or Cooling Coils
Heating or cooling coils
High or low temperature duties may require the addition of coils to act as heat exchangers to either warm or cool the medium before it enters the pilot valve or main valve dome. This ensures that extremeties of temperature do not affect the operation of the safety valve.
The use of such coils allows us to use standard pilots on valves with inlet temperatures in the range of -196°C (-320°F) to 260°C (500°F).
Field test connector
This provides verification of set pressure setting during normal system operation. The field test
An external pressure supply needs to be connected to the check valve via an isolating valve and pressure gauge. The external pressure should be admitted slowly through the supply isolating valve. When the supply pressure is greater than the system pressure the check valve delivery seat will open and the system seat will close.
Pressure can now be applied to the pilot and dome.
When set pressure is reached the pilot will open.
N.B. Pop action pilots will ‘pop’ open; this is the main valve set pressure. Modulating pilots will start to vent from their drain seat; this will occur at approximately 2% below the main valve set pressure.
Others
Similar to the spring loaded safety relief valves (see page 15), pilot valves can be fitted with:
•Packed lift levers.
•Ferrules (government rings).
•Test gags (max pressure 1480 Psig).
Available options
•Dual pilot assemblies.
•Dual pilot interlock system.
•Heated or unheated control cabinets.
•Dual outlet/full bore design.
•Differential pressure switch.
Dual pilots
If a process plant is running, it is earning a profit for its operator. Traditionally, when a valve required maintenance the plant had to be shut down, resulting in reduced earning time.
A solution to this is to install a second pilot on to the main valve and install a simple system of ball valves or an interlocked changeover valve system, thus allowing one pilot to be removed while the plant is still operating. We can offer either solution.
Remote unloader
This device enables the main valve to be opened remotely. It is a three way spool valve which can be operated electronically or pneumatically.
The valve is mounted into the dome line and allows a free flow from the pilot into the dome.
When remote operation is required, a signal (pneumatic or electrical) opens the exhaust vent of the spool valve and vents the dome, allowing the main valve to open.
The valve will normally be supplied mounted onto the main valve with the dome connected directly to the pilot.
When the spool valve is energised the dome will
vent directly to atmosphere. Remote Unloader
Inlet diameter 1 - 8"
Pilot description 2 Pop action, gas 4 Modulating, LP 8 Modulating, HP
Flange type 1 ANSI RF x RF 2 ANSI RTJ x RF O Special ANSI flange rating
1 150 x 150
Orifice designation D-T X = 8" x 10" x 10" full bore
Outlet diameter 2" - 10"
Accessories
A Remote pressure sensing B Back flow preventer C Cooling/heating coils D Screwed cap E External filter
**G Test gag
*L Liquid duty P Packed lever T Field test connector U Remote unloader S Special
Pressure range Psig (Barg)
Range Type 2 Type 4 Type 8
1 29 - 6170 29 - 100 1480 - 6170 (2.0 - 425.5) (2.0 - 6.8) (102 - 425.5)
2 >100 - 1480
(>6.8 - 102) These are min/max pressures of the pilot.
Several springs are required to cover these ranges
Main valve spring material 2 St steel 316
Z Inconel X750 (NACE) O Special
Main valve trim 1 St St 316 and PEEK 2 St St 316 and Viton 4 St St 316 and Buna N 8 St St 316 and Polyurethane 9 St St 316 and PTFE O Special
Main valve body code
1 Carbon steel SA 216-WCB
2 Carbon Steel SA 216-WCB (NACE) 3 St steel SA 351-CF8M (NACE) 4 St steel SA 351-CF8M
O Special
P
*Dual phase duties should use the liquid trim versions of the modulating pilot Types 4 and 8
**Test gag available to a max pressure of 1480 Psig
Size Orifice Rating A (ins) D (ins) B (ins) C (ins) C (ins) C (ins) Weight
(ins) Type 2 Type Remote lbs (kg)
4 and 8 pilot
1 x 2 D, E, F 150x150 4.13 4.50 1.69 14.00 19.00 9.00 42 (19)
300x150 4.38 4.50 1.69 14.00 19.00 9.00 45 (20.5)
600x150 4.38 4.50 1.69 14.00 19.00 9.00 45 (20.5)
900x300 4.94 4.75 2.25 16.00 21.00 11.50 53 (24)
1500x300 4.94 4.75 2.25 16.00 21.00 11.50 53 (24)
2500x300 4.94 4.75 2.25 16.00 21.00 11.50 53 (24)
1.5 x 2 D, E, F 150x150 4.88 4.75 1.69 14.50 19.50 9.50 46 (21)
300x150 4.88 4.75 1.69 14.50 19.50 9.50 49 (22)
600x150 4.88 4.75 1.69 14.50 19.50 9.50 49 (22)
900x300 5.88 5.50 2.63 17.00 22.00 12.50 57 (26)
1500x300 5.88 5.50 2.63 17.00 22.00 12.50 57 (26)
2500x300 5.88 5.50 2.63 17.00 22.00 12.50 57 (26)
1.5 x 3 G, H 150x150 5.13 4.88 1.69 15.00 20.00 10.25 55 (25)
300x150 5.13 4.88 1.69 15.00 20.00 10.25 62 (28)
600x150 5.13 4.88 1.69 15.00 20.00 10.25 62 (28)
900x300 6.38 6.75 2.62 18.25 23.25 13.50 79 (36)
1500x300 6.38 6.75 2.62 18.25 23.25 13.50 79 (36)
2500x300 6.38 6.75 2.62 18.25 23.25 13.50 79 (36)
2 x 3 G, H, J 150x150 5.38 4.88 1.81 15.25 20.25 10.50 55 (25)
300x150 5.38 4.88 1.81 15.25 20.25 10.50 60 (27)
600x150 5.38 4.88 1.81 15.25 20.25 10.50 64 (29)
900x300 6.56 6.75 2.44 19.25 24.25 14.50 93 (42)
1500x300 6.56 6.75 2.44 19.25 24.25 14.50 93 (42)
1500x600 6.56 6.75 2.44 19.25 24.25 14.50 93 (42)
2500x300 7.00 6.75 2.88 19.25 24.25 15.00 104 (47)
2500x600 7.00 6.75 2.88 19.25 24.25 15.00 104 (47)
Notes:
• Certified dimensions available on request.
• Dimensions A and B are for RF inlet, sensed integrally and remotely.
• Dimensions A and B are for RTJ inlet, sensed remotely.
• Add 1/2" to dimensions A and B for RTJ inlets 1" to 3" when sensed integrally.
• Add 3/4" to dimensions A and B for RTJ inlets 4" to 6" when sensed integrally.
• Add 1" to dimensions A and B for RTJ inlet 8"
when sensed integrally.
• Height may vary.
• Weight is approximate for Type 2 Pilot. For Types 4 and 8 Pilots add approx. 5kg.
• Cap withdrawal 40mm (1.6").