Most digital manometer units work by measuring and comparing the weights of fluids or gases between two different pressures. Any piece of equipment that relies upon a liquid or gas to operate requires a certain amount of pressure to function smoothly. Manometers detect the liquid pressure, sometimes in a U-shaped tube. Often featuring numerous settings and reading capabilities, these devices help to isolate pressure problems in systems from propane and natural gas to backyard barbecue grills. They are sometimes employed to troubleshoot heating ventilation and air conditioning (HVAC) systems and a variety of low-pressure pneumatic or gas systems.
Pressures are typically measured in terms of pounds per square inch (PSI) and may be displayed digitally or using a gauge or water-column inches. Other readouts may include pressure units such as pascal (Pa) and millibars (mbar). Devices typically operate within specified ranges of pressure, temperature, and materials. Digital manometer units might report positive, negative, or differential measurements between pressures and sometimes even flow readings with the integration of an anemometer. Some digital manometer products may provide information in imperial and metric units.
Digital manometer equipment operates on a simple yet accurate scientific principle of fluid displacement. In a traditional U-tube type manometer, water fills a tube in the shape of a U. Connecting one end to a gas line introduces gas pressure into the tube that displaces the water. How high the water rises in its other end is measured against a scale. This principle can be reproduced electronically and is so reliable that these devices are often used to calibrate more advanced equipment.
In terms of design, many digital manometer units are handheld, typically featuring digital electronics and resembling either digital stopwatches or handheld, TV-style remotes with alphanumeric readouts. Their functions are typically arrayed in a simple arrangement of a few buttons for a user-friendly interface. Readouts can feature various degrees of legibility, font size, or back lighting for use in low-light environments. Units can function independently or docked via cables or cradles. They may be available with assisting driver software to permit computer analysis.
Devices frequently feature dual output connectors, often at the top of the unit. Some digital manometer products link via a single output connector or cable, or may transmit their information wirelessly. Traditional analog devices rely upon metered gauges, or thermometer-style scales. Others are integrated within self-service blood pressure checking machines, such as those found in retail stores or pharmacies. Fixed and handheld units are used in laboratories, or they might be employed in the field for site and equipment testing in residential or commercial properties.