ABOUT PRESSURE INDICATORS
When envisioning complex pressure measurement and monitoring, one usually pictures high-pressure liquid or gas pipelines found in industrial and commercial environments, with their requisite controllers, gauges, and sensors. While complex industrial applications are certainly commonplace, a wide array of pressure applications require a much more low key approach to measuring and monitoring pressure.
This is an excellent job for pressure indicators, which are self-contained and well-suited for low pressure measurement (though some models can measure up to 10,000 psi).
What separates pressure indicators from other measurement devices such as gauges and sensors is the way they are designed and used. Pressure indicators, for example, are very useful for monitoring room pressures in pressure-positive cleanrooms or ventilation systems. They are also ideal for HVAC applications like setting balancing valves and measuring flue draft. Pressure indicators can also test pneumatic controls and regulators, pump performance, and leaks. They can monitor pressure drop across filters, and serve as a temporary test gauge replacement
Pressure indicators come in many shapes and sizes. They are often handheld and portable, (though most room pressure monitors used in demand ventilation systems and cleanrooms are wall mounted).
Pressure indicators are also synonymous with manometers (yet another generic term for pressure measurement device). And barometers -- used for meteorology, aeronautics, and heavy industry -- are also types of pressure indicators.
Pressure indicators, finally, generally utilize an internal pressure sensor. Though many types of sensors can be used, force collector- type sensors are the most common (led by piezoresistive and capacitive sensors). These electronic sensors employ a force collector such as a piston or diaphragm to measure the strain caused by force applied over an area. Simply put, pressure applies force to a piston or diaphragm which causes that element to move in relation to the amount of pressure. Sensors detect that movement (strain) and convert it to a unit of pressure.
Questions to consider when selecting a pressure indicator:
- Does the job at hand require high pressure or low pressure monitoring?
- Does the environment involve a pressure-positive cleanroom or demand ventilation system?
- Does the measurement task involve HVAC applications, pneumatic controls, or pump performance?