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How a Digital Pressure Gauge Works

Digital pressure gauges measure the difference between a system and its surrounding atmosphere. They can quantify water pressure and air pressure. These gauges are mainly used in fields in which precision and accuracy are critical, such as chemical processing plants. Unlike its mechanical counterpart, this type of gauge gives the user a larger reading range because of its high accuracy and very specific digital readouts.

Anatomy
- The digital pressure gauge used for reading tire pressure is one of its simplest forms. A pressure sensor is located at one terminal and it communicates the data to a central processing unit called the ̶0;microcontroller.̶1; An LCD, which is connected to the microcontroller, shows the value in different units. The whole system is battery operated and is usually enclosed in a plastic or metal casing.
Mechanism
- Using the strain gage sensing technology, a digital pressure gauge converts mechanical motion into an electronic signal. Pressure affects the physical properties of a wire (sensor) held under tension, therefore proportionally affecting resistance. This, in turn, makes the pressure measurable up to the decimal unit. The mechanical pressure gauge, on the other hand, employs the Bourdon tube technology. It uses a curved tube that directs the pressure from one end to a needle that flexes on the other end. The needle is positioned like the hands of a clock on a panel with a number readout. This is prone to parallax error, since it has limited resolution at different angles. The parallax error is a type of manual error in which a person̵7;s eye sees something different from what the gauge is showing because of visual perspective.
Other Features
- Portable handheld gauges are available for pressure tests such as leak testing, preventive maintenance, quality check and troubleshooting. Some displays are made of LED, which enables reading from a distance and in the dark. Some can be connected to a laptop or a desktop computer to produce charts in real time.
Maintenance
- Digital pressure gauges usually come standard with a shutoff valve between the gauge and the machine. This is used when any part of the process needs cleaning or calibration. Pipe coils or siphons are added to protect the gauge from extreme temperatures. Dampeners absorb pressure shocks and fluctuations. Chemical seals prevent corrosion and unwanted substances from reaching the sensor.

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