Series-MSAG-MSAH-XTBXConfiguration

Supported Applications

The Dwyer Series MSAG, MSAH, and XTBX diaphragm seals are designed for use with Mercoid Series D Bourdon Tube Pressure Switches. These accessories protect the pressure control's Bourdon tube from corrosive, viscous, or damaging media by isolating it with a flexible diaphragm actuated by system pressure.

Key application functions include:

• Preventing contact between process media and the Bourdon tube
• Handling gas, liquid, corrosive, viscous, or damaging media

Operating Conditions & Performance

The series supports pressure ratings of 2500 psig for MSAG and MSAH types, and 100 psig for XTBX. Seals cannot be used below 10" Hg vacuum.

Ambient and system temperature changes can affect controls and gauges with diaphragm seals, particularly at low pressures; ambient temperature compensation is available only when the control is mounted on the seal. Mercoid® diaphragm seals are not available for Range 15S & 16S Mercoid Pressure Controls.

Configuration Options

The series offers configurable options across three primary types: MSAG (Plain), MSAH (Clean-Out), and XTBX. Selection requires specifying the type, pressure range of control, diaphragm seal type desired, diaphragm material, pressure medium-to-seal contact surfaces material, size of seal-to-system connection, temperature range of pressure medium, and ambient temperatures.

Types and Configurations

• Type MSAG: Plain configuration with a 2-5/8" height (listed as 2-5/16" in source).
• Type MSAH: Clean-out configuration allowing field disassembly for cleaning or maintenance; features a 3-1/8" height.
• Type XTBX: Designed with FEP and PVC exposed surfaces.

Materials

Exposed surface materials vary by type as documented in the specification table:

• MSAG: Steel or 316 SS
• MSAH: Steel or 316 SS
• XTBX: FEP and PVC

Housing materials include rust-resistant finish steel or 316SS. Wetted materials are listed as Steel, 316 SS, FEP, and PVC.

Connections and Options

• Process Connection: 1/4" NPT (Flushing Connection) with a removable plug.
• Seal-to-System Connection Sizes: Available in 1/4", 1/2", 1", or 1½" NPT.
• Remote Mounting: Remote copper or S.S. tubing connection between seal and control is available, along with a mounting bracket (No. 33-25) for remote mounted controls.

Key Product Differences

The primary distinction among the series lies in the configuration and material composition:

• MSAG vs. MSAH: MSAG is a plain seal, while MSAH includes a clean-out feature for field disassembly.
• Material Differences: While MSAG and MSAH utilize Steel or 316 SS exposed surfaces, the XTBX type utilizes FEP and PVC.