Call Us: (973) 256-3000 Plast-O-Matic Valves, Inc.
1384 Pompton Avenue
Cedar Grove, NJ 07009 USA

PVC Line-Assisted Shutoff Valves

Series BLT • heavy-duty 2-way globe style valves for corrosive & ultra-pure liquids • Liquid Line Pressure to Open; Air Pressure to Close

Formerly Series ELT

Series BLT air shutoff valve

Photo at right is Series BLT, 3/4" through 2" pipe sizes. Below left is Series BLT in the 1/2" version.

Plast-O-Matic Series BLT globe-pattern air operated valves are ideal for handling pureliquids, chemicals, acids, and caustics where high flow and visual verification are important.


  • PTFE shaft & low-friction u-cup seals combine for ultra-smooth, non-sticking operation.
  • Clear acrylic cylinder for visual verification of valve position.
  • Fail-Dry® safety feature.
  • 1,000,000 cycle design,
  • Low pressure drop with high flow rates; pressure or vacuum service.
  • Bubble-tight sealing.
  • Manual set throttling limit stop available.


The valve disk or main seal is automatically opened with a minimum of 15 PSI line pressure from the process liquid. This will keep the valve open indefinitely. Standard shop air or hydraulic power is applied on the opposing side of a piston, attached to the PTFE shaft, to close the valve. The amount of air pressure required depends upon the liquid line pressure present in the valve. Operation requires a 3-way air solenoid valve to control the air or hydraulic pressure used. It is recommended to regulate the air pressure to 60 - 80 PSI. The air should be filtered and lubricated for longer valve life.

A minimum of 15 PSI air pressure (30 PSI for BLT 1/2", 20 PSI for the 1½" & 2" BLT) is required to close the valve at liquid pipeline pressures up to 25 PSI. As liquid process pressure in the pipeline increases, the minimum air pressure required to close the valve increases as well. The maximum pipeline pressure the valve will close against is 125 PSI.

Series BLT air shutoff valve in 1/2 inch pipe size

In situations where air pressure is not available, water pressure can be used so long as the pressure available is sufficient to actuate the valve. If hydraulic media is not clean, a filter should be used.

Valves should be mounted upright for best results and less strain on piping. Flow direction is indicated and should be adhered to for best results.

The Fail-Dry safety feature is a patented Plast-O-Matic design whereby the liquid seals and air pressure seals are separated by a vent, which will give indication of a valve problem before a system shutdown is necessary. For a complete explanation of the Fail-Dry system, please click here.

Sizes & Materials

Series BLT is available in 1/2", 3/4", 1", 1¼", 1½" and 2" pipe sizes. Standard valve body material is Geon® PVC. Cylinder walls are high-strength acrylic. Shaft is PTFE. External fasteners are stainless steel. Elastomeric seals are choice of Viton®, EPDM, or Buna-nitrile. For other materials, please contact the Plast-O-Matic Technical Department at 973-256-3000 or e-mail

Connections, Pressure Ratings

Standard connections are NPT. Optional connections are socket or flanged. Air inlet connection is 1/8" NPT. Maximum air pressure is 100 PSI. Minimum air pressure required to close the valve is 15 PSI (30 PSI for 1/2", 20 PSI for 1½" & 2"). Use of an air flow rate valve may be required to prevent water hammer, depending on your application.

Maximum liquid line pressure is 125 PSI. Minimum liquid line pressure is 15 PSI.


Series BLT automatic valves require air or hydraulic pressure to close and are normally open by liquid line pressure. In both models, dual u-cups seal against a pressure balanced PTFE shaft. This, in conjunction with a poppet seat at the valve orifice, results in a non-sticking design.

Throttling Option:

A very simple and inexpensive throttling limit stop to control flow is available for BLT. This is adjusted in the field to a set opening and the valve will always re-open to that point. If the line pressure remains constant, the flow will then remain constant.

Series BLT Dimensions:

dimensional drawing of Series BLT or BAT air shutoff valve
Size1/2" 3/4" 1" 1¼" 1½" 2"
A2 3/860.33 1/288.93 3/495.34 9/16115.95127.06152.4
B1 3/444.51 3/444.51 3/444.51 5/841.31 3/444.52 3/860.3
C5 3/8136.55 5/16 134.95 9/16141.26 3/8161.86 5/8168.28 7/8225.3
D7/819.91 5/3229.21 3/834.81 5/841.11 7/847.51 15/3229.2
E..1 15/1649.22 1/854.02 5/1650.82 1/263.5376.2
F2 3/860.33 76.24101.64 1/2114.36152.47 177.8
G..4 101.65127.05 3/4146.17 3/8187.28 1/2215.9

Point of clarification: The "D" dimension indicates distance from center of piping connection to bottom of valve. The "E" height indicates distance from center of piping connection to bottom of optional flange. The "G" dimension indicates length with optional flanges. The "B" dimension is a "maximum" dimension.

Please note that dimensions for 1/2" Series BLT shown here do not use the same letter references as the printed catalog or .pdf file.

Specifications & Ordering Information:

Pipe SizeCv FactorPressure RatingsModel Numbers
Minimum Air to Close
w/0-50 PSI Line Pressure
Minimum Air to Close
w/125 PSI Line Pressure
1/2"3.630 PSI
2,06 BAR
30 PSI
2,06 BAR
BLT050V-PV (Viton Seals)
BLT050EP-PV (EPDM Seals)
3/4"8.520 PSI
1,38 BAR
40 PSI
2,76 BAR
BLT075V-PV (Viton Seals)
BLT075EP-PV (EPDM Seals)
1"15.020 PSI
1,38 BAR
45 PSI
3,11 BAR
BLT100V-PV (Viton Seals)
BLT100EP-PV (EPDM Seals)
1¼"24.025 PSI
1,73 BAR
45 PSI
3,11 BAR
BLT125V-PV (Viton Seals)
BLT125EP-PV (EPDM Seals)
1½"33.035 PSI
2,42 BAR
60 PSI
4,14 BAR
BLT150V-PV (Viton Seals)
BLT150EP-PV (EPDM Seals)
2"60.030 PSI
2,07 BAR
55 PSI
3,80 BAR
BLT200V-PV (Viton Seals)
BLT200EP-PV (EPDM Seals)
Please Note: The air pressures required for closing, listed above, are not complete for all liquid line combinations. For example, the BLT150EP-PV requires 55 PSI air to close against 100 PSI liquid line pressure. The table above is not complete simply because it would be too cumbersome for this website. For more precise data, please refer to the catalog, or click here for the .pdf file.

To order with throttling limit stops, add "LS" to part number, after the seal material.
Example: BLT075V-LS-PV.
For Buna-nitrile seals, replace "V" or "EP" with "B". Example: BLT075B-PV
Maximum air pressure rating is 100 PSI/6,90 BAR
15 PSI minimum liquid process pressure is required for the valve to open or close.
Please note that the catalog and/or .pdf file documentation may refer to the previous part numbers for 3/4" through 2" sizes. The part number may say "ELT" instead of "BLT." Simply change the "E" to "B" and use the dimensions on this page.

Helpful Links:

.PDF file of Catalog ASO This catalog provides complete data and sample specifications for Globe Style Air Shut-off & Diverter Valves Series BAT, BLT, BST-NC, BST-NO, F, BFS.

Series BST-NC Normally-Closed designs similar in size and appearance, except the valve is fail-safe to close. Spring force keeps the valve closed and air is used to open the valve; no minimum line pressure requirement.

Series BST Normally-Closed designs similar in size and appearance, except the valve is fail-safe to open. Spring force keeps the valve open and air is used to close the valve; no minimum line pressure requirement.

Series BAT double-acting design similar in size and appearance, except the valve require air or hydraulic power to open and close; no minimum line pressure requirement.

Series BSD & BSDA Air-actuated shutoff valves for pressure and drain applications.

Index Page to all Air-Actuated Globe style Valves with a brief description of each. Includes compact valves, diverter valves, valves that use line pressure to open, double-acting valves, and more. This may be the page you used to arrive here.

Plast-O-Matic Valves, Inc. 1384 Pompton Avenue Cedar Grove,
NJ 07009 USA Phone: (973) 256-3000 Fax: (973) 256-4745
California Warehouse 4054 Brewster Way Riverside, CA 92501
USA phone: (951) 686-2852 Fax: (951) 686-6328
Email: Legacy home page: please click here