281.491.2331 13839 West Bellfort Street Sugar Land, TX
281.491.2331 13839 West Bellfort Street Sugar Land, TX
ISO 9001:2015
U.S. Patents
90 + U.S. Patents
Since 1954
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Where to Use

  • Upstream of sensitive pneumatic instruments as a standalone pressure control device or part of a conditioning system


Ready, Set, Go

Powering and protecting your pneumatic instruments just got easier thanks to the spring-loaded Welker I-Series Instrument Regulators. The ISD model reduces higher pressure filtered gas or air to a lower outlet pressure safe for your downstream instrumentation, helping prevent costly damage and interruptions to operation.

Data Sheet ISD Data Sheet

ISD Flow Data

Hex Adjustment
Sensitive Pressure Control

At Close Range

Multiple flow coefficients and pressure control ranges let you adapt the ISD to your instrument and application. The ISD Instrument Regulators are diaphragm-sensing for greater sensitivity, giving you more control when setting the outlet pressure. And with a hex head adjustment screw, field adjustments are quick and easy. A locknut prevents the spring setting from changing due to vibration to help maintain a constant outlet pressure and flow.

3 Part Configurations

Make Arrangements

Why make do with another regulator when you can customize a standard ISD? You have the power to choose the port layout that works best for your application and installation and arrange your accessories accordingly. The compact design and port configuration options allow the ISD to fit easily into a small enclosure or on a panel.

Standard Porting Configurations
Knurled Spring Housing

Get a Grip

Diamonds are a service tech’s best friend. The easy-to-grip knurled spring housing on the ISD keeps hands from slipping during maintenance. Because no special tools are required, maintenance is uncomplicated and quick.


ISD Instrument Regulator
Materials of Construction316/316L Stainless Steel, Buna Nitrile, and PCTFE
Others Available
Maximum Allowable Inlet Pressure6000 psig
Temperature Range*32 °F to 392 °F
Ports¼" FNPT Inlet, Outlet, Relief, and Gauge
Flow Coefficient (CV)0.02
Pressure Control Ranges0–25 psig
0–50 psig
0–100 psig
0–200 psig
Weight2 lb
Options(3) Port Configurations

*Operating at Temperatures Below 32 °F is Not Recommended and Could Result in Major Flow Reduction
*May Vary Based on Seal Material

Note: An upstream filter and downstream relief are required.