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Ashcroft Diaphragm Seals

The comprehensive line of Ashcroft diaphragm seals will meet a wide variety of application or installation requirements.  Over 30,000 variations are possible with the types, connections and materials available.

Model Index for Diaphragm Seals


Capsule Seal

Type 100, 101, 102, 103
 104, 105,106,107,108

Top Welded or Bonded

Type 200, 201, 202, 203
204, 205, 206, 207, 208 

Clamped Seals

Type 300, 301, 302, 303

All Welded Seals

Type 310, 311, 312, 315, 320
 330 400, 401, 500, 511

High Displacement Seals

Type 702,703,740, 741

Isolation Rings

Type 80, 81 

Quick Connect

Type 320

Can be dismantling for cleaning

Ashcroft Diaphragm Seal Selection

When selecting an Ashcroft diaphragm seal, consider the following:

Seal Mounting

- connects directly to the process by means of a female NPT thread.
- the diaphragm seal is attached to the process by means of a flange as specified in ASME B16.5
In-line Welded
- various types of welded-in diaphragm seals for flow-thru applications.

Diaphragm Types

- threaded-in capsule design enables the diaphragm to be removed and/or replaced.
- the diaphragm is welded directly to the top housing.
- Teflon® or Viton® diaphragm bonded directly to the top housing.
- metal, Viton®, Teflon®, or Kalrez® diaphragm materials are clamped between the top and bottom housing.

Top Housing

Ashcroft diaphragm seals (with the exception of Types 310, 320, 400 & 500 series) are normally furnished with a nickel/chrome plated carbon steel top housing. As an option, Ashcroft offers 316 stainless steel.

Types 310, 320, 400 & 500 series come standard with a 316L stainless steel top housing. A standard fill/bleed connection allows the seal and instrument to be evacuated and filled.

Lower Housing

Lower housings are available from Ashcroft in a variety of materials to fit your application needs.

Selection of the lower housing material is important since it is in direct contact with the process media.

Diaphragm Materials

The diaphragm is in direct contact with the process, and selecting the proper Ashcroft diaphragm is important.

Clamping Rings

Black epoxy painted carbon steel is standard for Ashcroft rings. 316 stainless steel is an available option.

Upper Flange Rings

ASME B16.5 nickel/chrome plated carbon steel flanged rings are standard. 316 stainless steel is optional.