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Diaphragm Seals
Extend the life and accuracy of your pressure measurement instruments with our high-quality diaphragm seals. Designed to protect gauges, transmitters, and switches from corrosive, viscous, or high-temperature process media, diaphragm seals provide a safe barrier without sacrificing measurement precision. Our selection includes threaded, flanged, inline, and sanitary diaphragm seals, available in a variety of materials, pressure ratings, and connection types to fit your specific application. Commonly used in chemical processing, oil and gas, water treatment, food and beverage, and pharmaceutical industries, these seals help maintain system integrity and reduce costly downtime. Built for durability and compliance, our trusted-brand diaphragm seals deliver leak-free performance, easy maintenance, and long-lasting reliability, making them an essential choice for demanding environments.
Filters 39 Results
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Features a flush mount diaphragm and all welded construction, ideal for food & beverage, pharmaceutical and sanitary marketsCan be used for remote mounting of pressure instrument(s) with capillary, see options & accessories belowWetted parts and all welded housing are constructed of 316 Stainless Steel for greater strength and durabilityAccommodates process connection pipes from 1-1/2" through 3" sizesClamped connection allows ease of installation and removal of seal for maintenance and cleaning
Save 30%$433.88
$305.24
Available for Purchase
Subject to factory lead times
Designed for applications requiring an NPT male threaded process connection and with a flush diaphragmFlush diaphragm construction prevents clogging and process material build-upConstructed with a 316 Stainless Steel housing and diaphragm for strength and durabilityAvailable instrument connection sizes are 1/4” and 1/2" with a process connection size of 1/2" NPT male to 2" NPT male
Save 30%$346.53
$243.79
Should ship between 03 Nov and 07 Nov
Subject to factory lead times
Designed for applications requiring an NPT male threaded process connection and with a flush diaphragmFlush diaphragm construction prevents clogging and process material build-upConstructed with a 316 Stainless Steel housing and diaphragm for strength and durabilityAvailable instrument connection sizes are 1/4” and 1/2" with a process connection size of 1/2" NPT male to 2" NPT male
Save 30%$434.83
$305.90
Should ship between 03 Nov and 07 Nov
Subject to factory lead times
Features a flush mount diaphragm and all welded construction, ideal for food & beverage, pharmaceutical and sanitary marketsCan be used for remote mounting of pressure instrument(s) with capillary, see options & accessories belowWetted parts and all welded housing are constructed of 316 Stainless Steel for greater strength and durabilityAccommodates process connection pipes from 1-1/2" through 3" sizesClamped connection allows ease of installation and removal of seal for maintenance and cleaning
Save 30%$433.88
$305.24
In Stock (58)Ships within 1 business day
Features a flush mount diaphragm and all welded construction, ideal for food & beverage, pharmaceutical and sanitary marketsCan be used for remote mounting of pressure instrument(s) with capillary, see options & accessories belowWetted parts and all welded housing are constructed of 316 Stainless Steel for greater strength and durabilityAccommodates process connection pipes from 1-1/2" through 3" sizesClamped connection allows ease of installation and removal of seal for maintenance and cleaning
Save 30%$433.88
$305.24
In Stock (40)Ships within 1 business day
Designed for applications requiring an NPT male threaded process connection and with a flush diaphragmFlush diaphragm construction prevents clogging and process material build-upConstructed with a 316 Stainless Steel housing and diaphragm for strength and durabilityAvailable instrument connection sizes are 1/4” and 1/2" with a process connection size of 1/2" NPT male to 2" NPT male
Save 30%$346.53
$243.79
Should ship between 03 Nov and 07 Nov
Subject to factory lead times
Designed to isolate the pressure measuring instrument from corrosive or viscous process mediaUtilize an all welded, all metallic housing design to eliminate potential leak pathsFor use with gauges with dial sizes of 2-1/2" and smaller, and pressure ranges no less than 100 psigHousing and diaphragm offered in a variety of materials to suit most applicationsA flushing port is available to clean wetted areas and prevent process media build up
Save 30%$209.46
$147.35
In Stock (7)Ships within 1 business day
Designed for applications requiring an NPT male threaded process connection and with a flush diaphragmFlush diaphragm construction prevents clogging and process material build-upConstructed with a 316 Stainless Steel housing and diaphragm for strength and durabilityAvailable instrument connection sizes are 1/4” and 1/2" with a process connection size of 1/2" NPT male to 2" NPT male
Save 30%$346.53
$243.79
Available for Purchase
Subject to factory lead times
Features a flush mount diaphragm and all welded construction, ideal for food & beverage, pharmaceutical and sanitary marketsCan be used for remote mounting of pressure instrument(s) with capillary, see options & accessories belowWetted parts and all welded housing are constructed of 316 Stainless Steel for greater strength and durabilityAccommodates process connection pipes from 1-1/2" through 3" sizesClamped connection allows ease of installation and removal of seal for maintenance and cleaning
Save 30%$433.88
$305.24
Should ship between 07 Nov and 14 Nov
Subject to factory lead times
The Ashcroft® 310 and 315 mini-diaphragm seals protect pressure measuring instruments. Used to ensure process compatibility, they are also applied when process media exhibit pulsation and the potential for plugging or freeze-up. An ideal choice for limited space installations.
$171.92
In Stock (27)Ships within 1 business day
The Ashcroft® 100 and 101 threaded diaphragm seals protect pressure measuring instruments. Used when process compatibility is required, these are also applied when media exhibit high temperature or has the potential to clog an instrument connection. Ideal for satisfying many challenging applications.
$564.29
Should ship between 21 Nov and 28 Nov
Subject to factory lead times
The Ashcroft® 100 and 101 threaded diaphragm seals protect pressure measuring instruments. Used when process compatibility is required, these are also applied when media exhibit high temperature or has the potential to clog an instrument connection. Ideal for satisfying many challenging applications.
$564.29
Should ship between 21 Nov and 28 Nov
Subject to factory lead times
The Ashcroft® 200 and 201 threaded diaphragm seals protect pressure measuring instruments. Used when process compatibility is required, these are also applied when media exhibit high temperature or the potential to clog an instrument connection. Ideal for satisfying many challenging applications.
$419.54
Should ship between 21 Nov and 28 Nov
Subject to factory lead times
The Ashcroft® 200 and 201 threaded diaphragm seals protect pressure measuring instruments. Used when process compatibility is required, these are also applied when media exhibit high temperature or the potential to clog an instrument connection. Ideal for satisfying many challenging applications.
Save 16%$521.13
$438.24
Low Stock (2)Ships within 1 business day
The Ashcroft® 320 in-line quick-connect diaphragm seals are designed to provide immediate dismantling and reassembly for cleaning process media between scheduled process runs for pharmaceutical and biotech applications. A very useful selection for those applications that do not require 3A sanitary ratings.
$257.04
Available for Purchase
Subject to factory lead times
The Ashcroft® 320 in-line quick-connect diaphragm seals are designed to provide immediate dismantling and reassembly for cleaning process media between scheduled process runs for pharmaceutical and biotech applications. A very useful selection for those applications that do not require 3A sanitary ratings.
Save 3%$271.71
$264.04
Should ship between 21 Nov and 28 Nov
Subject to factory lead times
The Ashcroft® 200 and 201 threaded diaphragm seals protect pressure measuring instruments. Used when process compatibility is required, these are also applied when media exhibit high temperature or the potential to clog an instrument connection. Ideal for satisfying many challenging applications.
$491.48
Should ship between 21 Nov and 28 Nov
Subject to factory lead times
The Ashcroft® 310 and 315 mini-diaphragm seals protect pressure measuring instruments. Used to ensure process compatibility, they are also applied when process media exhibit pulsation and the potential for plugging or freeze-up. An ideal choice for limited space installations.
$172.20
In Stock (150)Ships within 1 business day
The Ashcroft® 100 and 101 threaded diaphragm seals protect pressure measuring instruments. Used when process compatibility is required, these are also applied when media exhibit high temperature or has the potential to clog an instrument connection. Ideal for satisfying many challenging applications.
$564.29
Available for Purchase
Subject to factory lead times
The Ashcroft® 100 and 101 threaded diaphragm seals protect pressure measuring instruments. Used when process compatibility is required, these are also applied when media exhibit high temperature or has the potential to clog an instrument connection. Ideal for satisfying many challenging applications.
$564.29
Should ship between 21 Nov and 28 Nov
Subject to factory lead times
The Ashcroft® 200 and 201 threaded diaphragm seals protect pressure measuring instruments. Used when process compatibility is required, these are also applied when media exhibit high temperature or the potential to clog an instrument connection. Ideal for satisfying many challenging applications.
$419.54
Low Stock (1)Ships within 1 business day
The Ashcroft® 200 and 201 threaded diaphragm seals protect pressure measuring instruments. Used when process compatibility is required, these are also applied when media exhibit high temperature or the potential to clog an instrument connection. Ideal for satisfying many challenging applications.
$419.54
Should ship between 21 Nov and 28 Nov
Subject to factory lead times
An off-line seal with a threaded connection and all welded, all metallic housing design that does not utilize an o-ring or gasketCan be used for remote mounting of pressure instrument(s) with capillary, see options & accessories belowDesigned with a larger diameter diaphragm for higher displacement capabilityA variety of upper and lower housing and diaphragm materials are available to suit most applicationsA flushing port is available to clean wetted areas and prevent process media build up
Save 30%$345.75
$243.24
In Stock (34)Ships within 1 business day
An off-line seal with a threaded connection and all welded, all metallic housing design that does not utilize an o-ring or gasketCan be used for remote mounting of pressure instrument(s) with capillary, see options & accessories belowDesigned with a larger diameter diaphragm for higher displacement capabilityA variety of upper and lower housing and diaphragm materials are available to suit most applicationsA flushing port is available to clean wetted areas and prevent process media build up
Save 30%$345.75
$243.24
In Stock (13)Ships within 1 business day
Features a flush mount diaphragm and all welded construction, ideal for food & beverage, pharmaceutical and sanitary marketsCan be used for remote mounting of pressure instrument(s) with capillary, see options & accessories belowWetted parts and all welded housing are constructed of 316 Stainless Steel for greater strength and durabilityAccommodates process connection pipes from 1-1/2" through 3" sizesClamped connection allows ease of installation and removal of seal for maintenance and cleaning
Save 30%$433.88
$305.24
Available for Purchase
Subject to factory lead times
Designed for applications requiring an NPT male threaded process connection and with a flush diaphragmFlush diaphragm construction prevents clogging and process material build-upConstructed with a 316 Stainless Steel housing and diaphragm for strength and durabilityAvailable instrument connection sizes are 1/4” and 1/2" with a process connection size of 1/2" NPT male to 2" NPT male
Save 30%$346.53
$243.79
Should ship between 03 Nov and 07 Nov
Subject to factory lead times
Designed for applications requiring an NPT male threaded process connection and with a flush diaphragmFlush diaphragm construction prevents clogging and process material build-upConstructed with a 316 Stainless Steel housing and diaphragm for strength and durabilityAvailable instrument connection sizes are 1/4” and 1/2" with a process connection size of 1/2" NPT male to 2" NPT male
Save 30%$434.83
$305.90
Should ship between 03 Nov and 07 Nov
Subject to factory lead times
Features a flush mount diaphragm and all welded construction, ideal for food & beverage, pharmaceutical and sanitary marketsCan be used for remote mounting of pressure instrument(s) with capillary, see options & accessories belowWetted parts and all welded housing are constructed of 316 Stainless Steel for greater strength and durabilityAccommodates process connection pipes from 1-1/2" through 3" sizesClamped connection allows ease of installation and removal of seal for maintenance and cleaning
Save 30%$433.88
$305.24
In Stock (58)Ships within 1 business day
Features a flush mount diaphragm and all welded construction, ideal for food & beverage, pharmaceutical and sanitary marketsCan be used for remote mounting of pressure instrument(s) with capillary, see options & accessories belowWetted parts and all welded housing are constructed of 316 Stainless Steel for greater strength and durabilityAccommodates process connection pipes from 1-1/2" through 3" sizesClamped connection allows ease of installation and removal of seal for maintenance and cleaning
Save 30%$433.88
$305.24
In Stock (40)Ships within 1 business day
Designed for applications requiring an NPT male threaded process connection and with a flush diaphragmFlush diaphragm construction prevents clogging and process material build-upConstructed with a 316 Stainless Steel housing and diaphragm for strength and durabilityAvailable instrument connection sizes are 1/4” and 1/2" with a process connection size of 1/2" NPT male to 2" NPT male
Save 30%$346.53
$243.79
Should ship between 03 Nov and 07 Nov
Subject to factory lead times
Designed to isolate the pressure measuring instrument from corrosive or viscous process mediaUtilize an all welded, all metallic housing design to eliminate potential leak pathsFor use with gauges with dial sizes of 2-1/2" and smaller, and pressure ranges no less than 100 psigHousing and diaphragm offered in a variety of materials to suit most applicationsA flushing port is available to clean wetted areas and prevent process media build up
Save 30%$209.46
$147.35
In Stock (7)Ships within 1 business day
Designed for applications requiring an NPT male threaded process connection and with a flush diaphragmFlush diaphragm construction prevents clogging and process material build-upConstructed with a 316 Stainless Steel housing and diaphragm for strength and durabilityAvailable instrument connection sizes are 1/4” and 1/2" with a process connection size of 1/2" NPT male to 2" NPT male
Save 30%$346.53
$243.79
Available for Purchase
Subject to factory lead times
Features a flush mount diaphragm and all welded construction, ideal for food & beverage, pharmaceutical and sanitary marketsCan be used for remote mounting of pressure instrument(s) with capillary, see options & accessories belowWetted parts and all welded housing are constructed of 316 Stainless Steel for greater strength and durabilityAccommodates process connection pipes from 1-1/2" through 3" sizesClamped connection allows ease of installation and removal of seal for maintenance and cleaning
Save 30%$433.88
$305.24
Should ship between 07 Nov and 14 Nov
Subject to factory lead times
The Ashcroft® 310 and 315 mini-diaphragm seals protect pressure measuring instruments. Used to ensure process compatibility, they are also applied when process media exhibit pulsation and the potential for plugging or freeze-up. An ideal choice for limited space installations.
$171.92
In Stock (27)Ships within 1 business day
The Ashcroft® 100 and 101 threaded diaphragm seals protect pressure measuring instruments. Used when process compatibility is required, these are also applied when media exhibit high temperature or has the potential to clog an instrument connection. Ideal for satisfying many challenging applications.
$564.29
Should ship between 21 Nov and 28 Nov
Subject to factory lead times
The Ashcroft® 100 and 101 threaded diaphragm seals protect pressure measuring instruments. Used when process compatibility is required, these are also applied when media exhibit high temperature or has the potential to clog an instrument connection. Ideal for satisfying many challenging applications.
$564.29
Should ship between 21 Nov and 28 Nov
Subject to factory lead times
The Ashcroft® 200 and 201 threaded diaphragm seals protect pressure measuring instruments. Used when process compatibility is required, these are also applied when media exhibit high temperature or the potential to clog an instrument connection. Ideal for satisfying many challenging applications.
$419.54
Should ship between 21 Nov and 28 Nov
Subject to factory lead times
The Ashcroft® 200 and 201 threaded diaphragm seals protect pressure measuring instruments. Used when process compatibility is required, these are also applied when media exhibit high temperature or the potential to clog an instrument connection. Ideal for satisfying many challenging applications.
Save 16%$521.13
$438.24
Low Stock (2)Ships within 1 business day
The Ashcroft® 320 in-line quick-connect diaphragm seals are designed to provide immediate dismantling and reassembly for cleaning process media between scheduled process runs for pharmaceutical and biotech applications. A very useful selection for those applications that do not require 3A sanitary ratings.
$257.04
Available for Purchase
Subject to factory lead times
The Ashcroft® 320 in-line quick-connect diaphragm seals are designed to provide immediate dismantling and reassembly for cleaning process media between scheduled process runs for pharmaceutical and biotech applications. A very useful selection for those applications that do not require 3A sanitary ratings.
Save 3%$271.71
$264.04
Should ship between 21 Nov and 28 Nov
Subject to factory lead times
The Ashcroft® 200 and 201 threaded diaphragm seals protect pressure measuring instruments. Used when process compatibility is required, these are also applied when media exhibit high temperature or the potential to clog an instrument connection. Ideal for satisfying many challenging applications.
$491.48
Should ship between 21 Nov and 28 Nov
Subject to factory lead times
The Ashcroft® 310 and 315 mini-diaphragm seals protect pressure measuring instruments. Used to ensure process compatibility, they are also applied when process media exhibit pulsation and the potential for plugging or freeze-up. An ideal choice for limited space installations.
$172.20
In Stock (150)Ships within 1 business day
The Ashcroft® 100 and 101 threaded diaphragm seals protect pressure measuring instruments. Used when process compatibility is required, these are also applied when media exhibit high temperature or has the potential to clog an instrument connection. Ideal for satisfying many challenging applications.
$564.29
Available for Purchase
Subject to factory lead times
The Ashcroft® 100 and 101 threaded diaphragm seals protect pressure measuring instruments. Used when process compatibility is required, these are also applied when media exhibit high temperature or has the potential to clog an instrument connection. Ideal for satisfying many challenging applications.
$564.29
Should ship between 21 Nov and 28 Nov
Subject to factory lead times
The Ashcroft® 200 and 201 threaded diaphragm seals protect pressure measuring instruments. Used when process compatibility is required, these are also applied when media exhibit high temperature or the potential to clog an instrument connection. Ideal for satisfying many challenging applications.
$419.54
Low Stock (1)Ships within 1 business day
The Ashcroft® 200 and 201 threaded diaphragm seals protect pressure measuring instruments. Used when process compatibility is required, these are also applied when media exhibit high temperature or the potential to clog an instrument connection. Ideal for satisfying many challenging applications.
$419.54
Should ship between 21 Nov and 28 Nov
Subject to factory lead times
An off-line seal with a threaded connection and all welded, all metallic housing design that does not utilize an o-ring or gasketCan be used for remote mounting of pressure instrument(s) with capillary, see options & accessories belowDesigned with a larger diameter diaphragm for higher displacement capabilityA variety of upper and lower housing and diaphragm materials are available to suit most applicationsA flushing port is available to clean wetted areas and prevent process media build up
Save 30%$345.75
$243.24
In Stock (34)Ships within 1 business day
An off-line seal with a threaded connection and all welded, all metallic housing design that does not utilize an o-ring or gasketCan be used for remote mounting of pressure instrument(s) with capillary, see options & accessories belowDesigned with a larger diameter diaphragm for higher displacement capabilityA variety of upper and lower housing and diaphragm materials are available to suit most applicationsA flushing port is available to clean wetted areas and prevent process media build up
Save 30%$345.75
$243.24
In Stock (13)Ships within 1 business day
FAQ
- A diaphragm seal isolates a pressure instrument (gauge, transmitter, switch) from the process. A flexible diaphragm contacts the process fluid; behind the diaphragm is a sealed chamber of fill fluid that transmits pressure to the instrument. The instrument never touches the process. Used wherever the process would attack, plug, or freeze a standard instrument.
- Use one when the process is corrosive, viscous, hot, slurried, prone to crystallizing, contains solids, or has to stay sealed for sanitary reasons. Also when the instrument needs to be remote-mounted (off the process line). Adds cost and slightly slows response, but the seal protects an expensive transmitter for the life of the plant.
- Silicone oil is the default for general industrial service. Glycerin for food-safe and pharmaceutical work. Halocarbon and fluorinated oils for oxygen service or aggressive chemistry. Mineral oil and high-temperature oils for hot processes. The fill fluid has to be compatible with the process (in case the diaphragm ever fails) and stable at the operating temperature.
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About NISCO Inc.
NISCO offers a wide range of pressure gauges & instruments, diaphragm seals, thermometers, valves, and flow control products to the industrial and commercial marketplaces, as well as other resellers like ourselves. We can also provide other value-added services such as gauge repair, NIST traceable calibration, diaphragm seal assembly, and valve automation. NISCO takes pride in providing extensive product knowledge, helpful customer service, and market competitive pricing to help fit whatever need you may have because it is our goal to be regarded by our customers as the best supplier of pressure, temperature, and flow control products.