Type SMJ/SNJ Pipeline Diaphragm Seals

Type SMJ and SNJ Series diaphragm seals are flow thru type seals designed for pressure measurement applications involving jacketed pipelines where heated process fluids are used.

Theses diaphragm seals have slip-on flanges for ease of installation and alignment. Socket weld jacket connections are included for field installation.

The SMJ model is butt welded directly into the customer’s jacketed pipeline, whereas the SNJ includes a flange. Type SMJ and SNJ seals are continuous duty and feature a welded diaphragm seal design with the diaphragm welded directly onto the instrument housing.

The interior of the diaphragm top is contoured to fit the movement of the diaphragm at maximum allowable deflection. This minimizes distortion. A filling screw is provided standard.

SMJ and SNJ jacketed seals are available with 316 ELC stainless steel diaphragms and exposed parts. Other materials are available.

Jacket pipe, connections, and flanges are Schedule 40 carbon steel. Standard seals are furnished with ANSI Class 150 or 300 flanges.

The SMJ operating pressure is flange dependent. The SMJ seal pressure rating conforms to the Schedule 40 process pipe rating of 1500 psig at 100°F (103 bar at 38°C).

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