Pressure gauges are a crucial component of instrumentation toolboxes in a variety of industries. Differential gauges, used to measure the difference between two applied pressures, are specialized pressure gauges with essential applications in the cryogenic transport and HVAC industries.
Modern differential pressure gauges evolved from duplex or dual pressure gauges. While duplex pressure gauges display the individual pressure readings from two separate points, differential pressure gauges simplify the results by calculating the measurements’ difference. They measure pressure at two separate points, take the difference (PSID) between the two, and display that difference in a singular locale (either analog or digital).
Common Applications
WIKA Instrument Corporation produces a full line of differential pressure gauges commonly utilized to monitor the status of a filter in a process or transport stream. When the differential pressure reaches a specified level, this is a clear indication that a filter is blocked–in this way, the differential gauge serves as a monitor for the system.
While filter status is the most frequent application, WIKA’s gauges are the workhorses of choice when production demands careful monitoring of tank fill levels, room or building pressure, or air flow in industrial ovens, laminar flow hoods, or air ducts.
These process industry designed differential pressure gauges are built to withstand stressful operating conditions and therefore feature:
- Stainless steel sealing bellows
- Stainless steel fabrication for corrosive environments
- Accuracy of readings to ± 1.5% of span
WIKA also offers a series of handheld digital pressure transmitters, and several (including Model CPH 6200-S2) are suitable for measuring differential pressure when used in conjunction with connected pressure transmitters. Simply put: these reliable, process-hardened differential pressure gauges will not fail when and where they are most needed.
Cryogenic Utility
Differential pressure gauges are vital tools in the cryogenic transport industry. Gases such as oxygen, argon, and nitrogen are transported in liquid phase, which requires low temperature and applied pressure. Because the gas is pressurized, it’s important to know just how much is present. An accurate reading cannot be accomplished by simply taking the head pressure from the tank, so it is necessary to determine the differential pressure by taking the total pressure and subtracting the head pressure to get the liquid level (the weight of the liquid).
Tank cars in cryogenic transport typically have a liquid-level gauge, as well as a differential pressure gauge to measure the vapor pressure on the tank. Typically these are of stainless steel design, so that most of the transported liquefied gases are not corrosive to the material.
HVAC Utility
Beyond manufacturing and plant applications, the HVAC service industry is increasingly reliant on WIKA’s differential pressure gauges. The air2guide series, developed specifically for HVAC use, outperforms competitor models, whether measuring overpressure, negative pressure or differential pressure. This line, designed for air handling and ventilation-system applications, includes both mechanical and electronic differential pressure gauges that are ideal for filter monitoring in both clean rooms and in dust-collection systems.
Because many details must be taken into consideration when selecting differential pressure gauges, WIKA’s technical advisors can help you identify and produce a differential pressure gauge for your specific application requirements.