Pressure & Temperature

Pressure instruments are a critical category of measurement devices used in various industries to monitor and control pressure levels in a wide range of applications. Pressure measurement is vital for ensuring the safety, efficiency, and functionality of processes and equipment. Omni offers a wide array of pressure instruments including: 

  • Analog Pressure Gauges
  • Digital Pressure Gauges
  • Differential pressure Gauges
  • Absolute Pressure Gauges
  • High Accuracy Test Gauges
  • Vacuum Gauges & Strain Gauges
  • Pressure Switches
  • Pressure Transducers
  • Digital or Analog Transmitters & Manifolds  

There are three general types of pressure instruments each with its own principle of operation including pressure gauges, pressure transmitters and pressure switches. Pressure gauges are among the most commonly used pressure instruments in manufacturing industries. These gauges can either be digital or mechanical. Mechanical gauges use elements like bourdon tubes, diaphragms, or bellows to convert applied pressure into a mechanical motion that will be shown on a dial. 


They are typically used for relatively low to medium pressure ranges and come in various designs, including dial gauges, capsule gauges, and differential pressure gauges. Digital pressure gauges are used when higher precision and digital data output are required and to do that the gauge uses electronic sensors to measure that pressure and provides a digital read of the pressure value. Pressure transmitters are either analog or digital. While analog converts pressure signals into analog electrical signals, typically 4-20 mA or 0-10 V, for transmission to a control system or data acquisition equipment, they offer high accuracy and are commonly used in industrial process control.

Digital transmitters convert pressure signals into digital data, often using protocols like HART or Profibus, this allows for more advanced communication and diagnostics capabilities. Lastly is pressure switches, which can be either mechanical or digital. Mechanical switches are designed to open or close an electrical circuit when pressure crosses a specific threshold. These are used more often in situations with the need for simple on/off switches such as pump protection and safety interlocks. Electronic pressure switches use electronic sensors and circuits to provide more precise pressure control and can offer programmable setpoints and hysteresis.

 Temperature instruments are essential tools to measure temperature in various industrial, scientific, and environmental applications. These instruments employ different technologies and principles to measure temperature accurately. We offer: 

  • Thermocouples
  • RTD’s
  • Digital & Analog Thermometers
  • Fluid Expansion Temperature Devises
  • Digital & Electric Temperature Sensors 

Thermocouples are one of the most commonly used temperature measurement devices. These devices consist of two different metal wires joined together at one end, when this area is exposed to a temperature change, voltage is produced proportional to the temperature change. This voltage is measured and converted to a temperature reading.

Resistance temperature detectors or RTD’s are sensors that rely on a change in the electrical resistance of a material, usually pure elements like platinum, that changes the temperature. As the temperature increases, the resistance of the RTD element increases as well, offering high accuracy and stability. Infrared thermometers or pyrometers measure temperature by detecting the amount of infrared energy emitted from an object. The amount of emitted infrared energy is directly proportional to the temperature of the object; this is what allows pyrometers to be used as non-contact temperature measurement devices.

While there are many more types of temperature measurement instruments available like fiber optic or digital sensors, gas or liquid-in-gas thermometers and more, it is important to remember temperature process instruments are often installed in harsh environments, so they may need periodic verification, maintenance, and adjustments to ensure they are measuring temperature within expected limits. Omni Services can offer these in exotic alloys such as Monel & Hastelloy C-276.



The Northeast's leading hose and accessories distributor with retail service stores located throughout Massachusetts, New Hampshire, Connecticut, Maine, New Jersey, New York, North Carolina, Delaware and Canada. With over 40 years of specializing in fluid conveyance, we continue to provide products of the highest quality and excellent service.


Corporate Address: 12 East Worcester Street Worcester, MA 01604 USA View Map on Google