Section No. 3.6
PT988
Series PT988 Pneumatic Liquid Level Switch Application WellMark’s PT988 Pneumatic Level Switch is designed for horizontal mounting in a tank or vessel through threaded or flanged pipe connections (will work in an API 2" full coupling) and is excellent for applications where space is a factor. It can be externally caged for vessel isolation and can be used as a high or low level alarm, as well as a liquid level control. In addition, it can be switched from direct to indirect action simply by inverting the unit 180˚. The PT988 features a 3-way snap-acting pilot (0 to full output using 20-30 psi supply pressure) or order it with an optional throttling pilot (3 to 15 psi output with a 20 psi supply pressure).
Features • Snap or Throttle • Small, Compact • Direct or Indirect Action • Economical
Specifications
2 1/4 15 10
WELLMARK
30
5
25
psi
5 7/8
Optional Body
15 10
WELLMARK
30
5
25
0
psi
6 15/16 4"
6 1/2 1"NPT (Typ.)
2 1/4
PTP988 Level Switch With External Cage
10
20
25 30
0
psi
5 7/8
15
WELLMARK
Direct Acting
15 10
20
WELLMARK
15 10
20
Indirect Acting
0
psi 15
10
20
0
psi
30
5
25
Will Work In An API 2" Full Coupling
30
5
25
A rise in fluid level resulting in a decrease of pilot output. This is accomplished when the pilot is in the upward position.
psi
30
5
25
0
A rise in fluid level resulting in an increase of pilot output. This is accomplished when the pilot is in the downward position
The
4 9/16
2" NPT
20
As liquid within the vessel varies, linear movement of the float is converted to rotary movement of the actuator assembly. In the snap acting mode, as the actuator pad moves closer to the nozzle, supply pressure is diverted to signal pressure, tripping the shuttle pilot to either full output pressure, energizing end-device, or to zero output pressure, de-energizing end-device. In the throttling mode, as the actuator pad moves closer to the nozzle, supply pressure is diverted to output pressure, resulting in modulating pressure to the end-device.
2" NPT
0
Operation
9 1/4 5 9/16
20
Body . . . . . . . . . . . . . . . . . Plated Steel Std. (S.S. available) Float . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Stainless Steel (Collapse pressure: 2500 psi) Wetted Parts . . . . . . . . . . . . . . . . . . . . . . . . Stainless Steel Pilot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Stainless Steel
PTP988 Level Switch
5
Materials
Dimensional Data
5 3/8
Max. Working Pressure . . . . . . . . . . . . . . . . . . . . . . . 1500 psi Supply Pressure . . . . . . . . . . . . . . . 20 psi Min. – 30 psi Max. Operating Temperature . . . . . . . . . . . . . . . . . . . -40˚F to 275˚F Process Connections . . . . . . . . . . . . . . . . . . 2" MNPT Standard Pilot Connections . . . . . . . . . . . . . . . . . . . . . . . . . . 1/4" FNPT Pilot Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Snap Acting Throttling
Company, L.L.C. • Oklahoma City, Oklahoma • Tel: (405) 672-6660 • Fax: (405) 672-6661 • wellmarkco.com
©2009 The WellMark Company, L.L.C. • Litho USA • WMPT988-5/09 • All registered trademarks are the property of their respective owners.
15
Section No. 3.6
Series
PT988
PT988 Pneumatic Liquid Level Switch Determining the Model Number
Various Pneumatic Hook-Ups
Example given: Standard Model PT988-2S-1, 2" Screwed, SnapActing Level Switch.
Supply
In
Single Unit Hook-Up
MODEL PT988-2 S-1
Out
End-Device
PT988
End-Device Out PT988
In In In Multiple Unit Hook-Up with Output If any of above should alarm, the “Supply” would be blocked and the output would
Supply In Out PT988
Parts List
Out PT988
Out PT988
In In In Should the alarm device be something with a restricted orifice (such as an AMOT 2400), the “Supply” to the alarm and the “Supply” to the PT988 should be the same. CAUTION: The “Trip” port of the “AMOT” CANNOT be utilized as the “Supply” to the “IN” port of the PT988. On alarm, the PT988 blocks the “IN” port and opens “OUT” to “EXHAUST.” 3
14
7
4
8
9
15
1
19
18 21
11
33 17
36
13
37 32
2
23
14 30 34 24
38
12
40
10 15
28 26 27
25
psi
39
15
29
20
WELLMARK 25
34 25 41 31
WELLMARK
30
5 6
5
20
20
16
Part No. 30216 30215 20433 20432 20434 20431 10482 20439 20783 004102-P 20558 10485 10500 10602 10603 20136 20562 10601 20436 05000-0173 10575 10642 20035 30276 30277 30278 20000 10024 10025 10003 10004 10522 20606 10604 10001 20519 20559 20549 10530 10063 10273 10005
Trip
0
The
Qty. 1 1 1 1 1 2 1 1 1 1 1 1 1 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 4 1 1 2 1 1 1 1 2 1 1
AMOT
0
Item Description 1 BODY, CARBON STEEL 2 PORT, STAINLESS STEEL 3 RETAINER, STAINLESS STEEL 4 FLOAT ARM, STAINLESS STEEL 5 PIN, STAINLESS STEEL 6 SPACER, STAINLESS STEEL 7* POLYPAK, FLUOROMYTE 8 WIRE, SNAP, S.S. (SNAP PILOT ONLY) 8 WIRE, THROTTLE, S.S. (THROTTLE PILOT ONLY) 9* O-RING, VITON ® 10 PORT, STAINLESS STEEL 11 SET SCREW, STAINLESS STEEL 12 NYLOCK NUT, STAINLESS STEEL 13 WASHER, PLASTIC 14 WASHER, PLASTIC 15 VENT ASSEMBLY, BRASS 16 PILOT BODY, S.S. (THROTTLE PILOT ONLY) 17 INSERT, NYLON 18 CAP, STAINLESS STEEL 19* O-RING, BUNA-N 20 FLOAT, STAINLESS STEEL 21 NAME PLATE 22 ORIFICE PLATE, S.S. (THROTTLE PILOT ONLY) 23 PILOT NOSE, S.S. (SNAP PILOT ONLY) 24 PILOT SEAT, S.S. (SNAP PILOT ONLY) 25 PILOT CAP, S.S. (SNAP PILOT ONLY) 26 PILOT SPOOL, DELRIN ® (SNAP PILOT ONLY) 27* PILOT SEAT, URETHANE (SNAP PILOT ONLY) 28* PILOT SEAT, URETHANE (SNAP PILOT ONLY) 29* PILOT GASKET, CORPRENE (SNAP PILOT ONLY) 30* DIAPHRAGM, BUNA-N (SNAP PILOT ONLY) 31 SCREW, S.S. (SNAP PILOT ONLY) 32* SEAT, VITON ® 33 SCREW, STAINLESS STEEL 34* SCREW, S.S. (SNAP PILOT ONLY) 35 CAP TUBE, S.S. (SNAP PILOT ONLY) 36 CAM, STAINLESS STEEL 37 ACTUATOR, STAINLESS STEEL 38 FLAPPER, STAINLESS STEEL 39 PRESSURE GAUGE 40 JAM NUT, STAINLESS STEEL 41 SPRING, S.S. (SNAP PILOT ONLY) *Recommended Spare Part
Out PT988
psi
30
Pilot Mode S • Snap T • Throttle
Out PT988
10
Size 2 • 2" Screwed F • ANSI Flange (Specify: Size,Rating)
Supply
5
Options 1 • Standard
10
Series PT988
SNAP PILOT
16 22
39
THROTTLE PILOT
Company, L.L.C. • Oklahoma City, Oklahoma • Tel: (405) 672-6660 • Fax: (405) 672-6661 • wellmarkco.com ©2009 The WellMark Company, L.L.C. • Litho USA • WMPT988-5/09 • All registered trademarks are the property of their respective owners.