Blog Pressure Switches

UL-Rated 703-U/UJ Pressure Switches Achieve Long Life in Explosive Environments

Gaseous or liquid fluid systems in hazardous locations demand the toughest pressure switches. These components must incorporate heavy-duty designs that offer exceptional accuracy despite harsh environmental conditions. They must also carry the right safety ratings, guaranteeing reliable operation in applications like offshore exploration and petrochemical processing. 

Our 703-U and 703-UJ Series of UL-rated, explosion-proof pressure switches fit the bill. These heavy-duty components feature a corrosion-resistant stainless steel construction and UL ratings for hazardous locations, including:

  • Class 1: Division 1, Groups A, B, C, D
  • Class 2: Division 1, Groups E, F, G

With high overpressure capabilities and a NEMA Type 7 explosion-proof rating, the 703-U/UJ Series integrate a rugged piston design, which enables these switches to withstand high pressure spikes, shock and vibration. The 703-U Series features factory-set fixed pressure, while the 703-UJ features field-adjustable pressure. Designed for easy field adjustment, the 703-UJ also incorporates a tamper-resistant locking mechanism to maintain set point integrity.

Additional features and specifications of the 703-U/UJ Series include:

  • Pressure range: 6 to 5,000 PSI
  • Temperature range: -40 to +180°F (703-U Series)
  • Pressure connection: 1/4-inch–18 NPT (male) and 1/2-inch–14 NPT (male)
  • Single pole double throw (SPDT) option
  • Double pole double throw (DPDT) option
  • 1/2-inch NPT electrical connection with five full threads for conduit engagement
  • Factory-sealed lead wires — Type UL 1015 AWG #18, 24 inches long
  • Hydraulic and electric modules AISI 316 stainless steel

Thanks to their durable construction, 703-U/UJ pressure switches boast exceptional accuracy and repeatability — even in explosive environments. And, they guarantee a long service life; the units’ snap-action electrical switch is tested to 1 million cycles. For these reasons, the 703-U and 703-UJ Series are ideal for applications like off-shore exploration, petrochemical processing, oil and gas pipelines, control panels and industrial OEM equipment.

To learn more, please visit our product page.


Sensing Elements Take Front and Center On Our New Website

At Sigma-Netics, we’re excited to announce the launch of our brand new website, which has made it easier than ever for you to learn about our new line of pressure transducers. Thanks to the site’s sleek, user-friendly design, you can also explore our technical resources, configure your own sensing element, learn about our company and more.

Browse our products with ease. Whether high pressures, radiation or fatiguing conditions—it doesn’t matter. Our ruggedized sensing elements stand up to the toughest industrial and aerospace applications with high accuracy and reliability. You can find more information about our high-performance products on our newly designed homepage, as well as on the navigation bar along the top.

Get a quote for sensing elements in just a few clicks. You can specify and receive a quick quote for our pressure switches, pressure transducers and metal bellows. Simply click here to fill out your contact information and application details. You also have the option to upload and send us any drawings or related files if you need a custom configuration.

Explore our technical resources. Toward the bottom of our homepage, you’ll find a sampling of our latest technical resources, including featured videos, white papers and blog posts. For a deeper dive into this content, you can click on “technology resources” at the top of our site.

Learn more about our company. In addition to learning more about our products, you can learn more about our company—including our history, manufacturing capabilities, quality certifications and job openings. We even have an option for you to provide us with feedback as part of our quality management system.

To get started, check out our new home page.

Blog Pressure Transducers

Explore the SST 74X-UV Pressure Transducer In Our New Video

Check out this quick overview of our SST 74X-UV Submersible Vehicle Depth Pressure Transducer. This compact, 90-gram model features shallow diaphragm sensors and a configurable flange design for outboard or inboard bulkhead installation. Units include an all-welded hermetic construction that resists shock and vibration.

The SST 74X-UV Series is ideal for many demanding applications, including unmanned underwater vehicles, salt spray environments, high-viscosity fluid applications and more. You can learn more about its features and specifications in our latest video.

Blog Pressure Transducers

Explore Our Radiation-Tolerant MV/V Pressure Transducer [Video]

The SST 64X-RT Series is ideal for a wide range of demanding applications—from satellite propulsion systems to reactor pressure management. Learn more about its features and specifications in our latest video.


An Important Update About Sigma-Netics Operations During the COVID-19 Pandemic

As all of us confront the COVID-19 crisis, we wanted to let you know about the status of our operations. Sigma-Netics is an essential manufacturing business as a critical supplier in defense and medical supply chains. Both our New Jersey and Virginia facilities continue to operate—accepting new orders and shipping existing orders for pressure switches, pressure sensors and metal bellows.

The health and safety of our customers and employees is our primary concern, and we have undertaken additional sanitation measures and are practicing social distancing within our facilities. All employees not directly involved in assembly or manufacturing are working from home.

We will continue to monitor global and domestic conditions, and we will provide updates on changing business conditions if they occur.

Blog Pressure Transducers

Satisfying the Unique Pressure Sensing Needs of Submersible Vehicles

Recent growth in unmanned underwater vehicles (UUVs) across several industries is also creating a need for depth transducers that can satisfy unique sensing and instrumentation requirements. Not only must UUVs operate in difficult conditions, their designs are as varied as their missions. That’s why we introduced a depth measurement device for use with submersible vehicles — the SST 74X-UV Series transducer.

Sigma-Netics SST74X UV Transducer

Our SST 74X-UV transducer meets the submersible industry’s demand for precise depth measurement, boasting accuracy of ±0.15 percent full scale output (FSO) total error band (TEB). The sensor is also versatile, featuring a configurable-flange design that allows outboard or inboard bulkhead installation along with digital and analog outputs to allow designers to connect to their choice of instrumentation. Additional features and specifications include:

  • An easily cleanable wetted area.
  • Outer diameter: 0.75 inches (19 millimeters) max.
  • Lightweight: <0.2 pounds (90 grams).
  • Standard ranges: 0-100, 250, 500, -750, 1500, 2000, 3000, 5000, 7000, 10000 psia/psig/psis.
  • Wetted parts made from 15-5 PH stainless steel or Inconel.

Greater Design Freedom

The SST 74X-UV is the latest in our growing line of Sigma-Netics pressure transducers that perform in harsh operating environments. By combining accurate pressure sensing with a configurable-flange design and both analog and digital outputs, the SST 74X-UV transducer gives engineers the freedom they need to implement depth measurement into their UUV designs.

For more information about Sigma-Netics’ SST SST 74X-UV depth transducer, visit


Announcing Our Recent AS9100D Certification

We’re pleased to announce we were recently awarded AS9100D approval for the design and manufacture of our pressure switches, pressure transducers, metal bellows and other products.

Developed by SAE International, AS9100D is a globally recognized quality management standard for the aviation, space and defense industries and incorporates the latest ISO 9001:2015 requirements.

The certification represents our ongoing commitment to improving our product quality even further while also satisfying our growing base of aerospace, defense and commercial space customers.

Blog Pressure Switches

Pressure Switches Combine Accuracy and Reliability for Oil and Gas Operations

Pressure switches for oil and gas facilities have to meet a set of challenging requirements. Not only should the switch provide exceptional accuracy and reliability, but it also must be suitable for use in hazardous locations—and carry the safety ratings to prove it.

Our Model 703-U and 703-UJ explosion-proof pressure switches with piston actuation combine uncompromising safety and protection with the accurate, reliable switching that mission-critical operations demand. The switches are listed for use in hazardous locations as specified by UL Class 1 Division 1, Groups A, B, C and D and Class 2 Groups E, F and G. And, they are NEMA Type 7 Rated for explosion protection.

They also feature a rugged, piston-actuation design to ensure optimal reliability. That’s because switches with a piston-based design are particularly able to manage high pressure spikes, leaks, vibration, shock and thermal extremes without losing accuracy or failing prematurely.

The pressure switches provide two options for safe and secure control of set points:

  • Model 703-UJ has been designed for easy field adjustment, letting users adjust pressure levels as conditions change. Once the setting is in place, 703-UJ’s tamper-resistant locking mechanism keeps it secure.
  • Model 703-U, which has factory-set pressure.

Along with its piston design, the highly rugged Model 703-U/UJ features:

  • NEMA Type 7 Rating for explosion protection.
  • 316 stainless steel construction to resist corrosion.
  • High overpressure capability.
  • Pressure handling up to 5000 psig.
  • Wide operating temperature range of -40°F to 180°F
  • Long lifetime — the snap-action switch has been tested to 1 million cycles.

Model 703U/UJ pressure switches are suitable for a wide range of upstream and downstream oil and gas operations such as offshore exploration, petrochemical processing and oil and gas pipelines. Additional applications include industrial OEM equipment and control panels.

To learn more about pressure switches for harsh environments, download our white paper.

Blog Pressure Switches

New Paper Explores How Pressure Switch Customizations Overcome Design Challenges

Download The White Paper

Pressure switches are often considered commodity items. But for many mission-critical or demanding applications—including aerospace, pharmaceuticals and chemical processing—your switch may require a custom mechanical design or electrical features that go beyond what commercial off-the-shelf switches can offer. With a little extra engineering, you can boost the performance of your switch and even overcome challenges your pressure system may be experiencing as a result of its operating environment.

In a new white paper, we explore some recent applications that demonstrate how custom-engineering our pressure switches has improved the functionality of the switch—as well as the reliability of the overall system.

Blog Custom Pressure Switches Pressure Switches Pressure Transducers

Flush-Mount Pressure Switches—And Transducers Too

Food, pharmaceutical and chemical processes often use tubular equipment to mix, transport or store materials. In these applications, it’s a good idea to keep any internal switches or sensors from protruding too far into the tube—where they can create a toehold for material buildup or impede flow. That’s where our newest pressure switch design comes into play.

This custom switch’s sensing element has been designed and manufactured to match the interior curvature of a specific food processing machine. The only part that protrudes into the flow within the machine is a low-profile, seamless seal that provides no place for materials to hang up during production.

While this particular flush-mount switch was designed for a specific use, the same approach can be applied to a wide variety of processing machines. We can alter the design of the switch for tubular structures with internal diameters as small as three inches.

We’ve also created a similar design for flush-mount pressure transducers.

Click here to learn more about our custom pressure switch capabilities.