What Is a Digital Pressure Gauge?
A digital pressure gauge is a machine used to measure pressure.
They are used for monitoring and controlling oil pressure, water pressure, and atmospheric pressure in various industrial machines, facilities, and analytical instruments. Depending on the application, there are waterproofed gauges and other types of gauges. The choice should be made according to the fluid (dry air, mist air, steam, oil, etc.) for which pressure is to be measured and the upper limit of applied pressure.
In recent years, many pressure sensors use a method in which pressure is measured by a part called a diaphragm, converted into an electrical signal, and output to a monitor.
Uses of Digital Pressure Gauges
Pressure gauges are used in semiconductor gas supply systems, machinery and equipment in various industries such as petroleum, paper, and chemicals, and in chemical analysis equipment. Therefore, the nature of the fluid to be measured varies. It is necessary to select the appropriate sensor according to the target fluid to be measured (gas, liquid, flammable, corrosive, etc.).
The reference pressure (absolute or atmospheric) also differs depending on the device. In addition, there are two types of instruments that use atmospheric pressure as a reference: those that measure negative pressure and those that measure positive pressure.
Principle of Digital Pressure Gauges
Pressure gauges used in recent years measure pressure using a pressure-receiving element called a diaphragm. The pressure received from the fluid causes the diaphragm to deform slightly. There are two types of pressure measurement methods using a diaphragm that show the deformation and change of the diaphragm: semiconductor strain gage type and capacitance type.
1. Semiconductor Strain Gauge Type
This method uses an electrical conversion element to detect the strain of the diaphragm and measure the pressure. There are three types of semiconductor strain gages depending on the internal structure: bulk type semiconductor strain gages, vapor-deposited (thin-film) type semiconductor strain gages, and diffusion type semiconductor strain gages.
Bulk Semiconductor Strain Gages
Bulk semiconductor strain gages are used by bonding a semiconductor strain gage to a metal diaphragm.
Evaporated (Thin-Film) Semiconductor Strain Gages
A thin film of semiconductor strain gage is formed directly on a metal diaphragm. This type is widely used because it is not affected by adhesion.
Diffusion-Type Semiconductor Strain Gages
This method uses a single-crystal silicon wafer to create a diaphragm. Although it cannot handle high pressure, it can be mass-produced and is inexpensive.
2. Capacitance Type
This is a method in which an electrode is placed across from the diaphragm and the displacement between the electrode and the diaphragm is caught as capacitance. In this method, the diaphragm is made of metal, ceramic, or silicon.
How to Select a Digital Pressure Gauge
When selecting a digital pressure gauge, you should pay attention to the following
1. Measuring Range
The most important factor in selecting a digital pressure gauge is whether or not it can handle the pressure range you wish to measure. Since the pressure range varies depending on the type of fluid, it is necessary to confirm in advance whether the pressure gauge can measure in the range suitable for the purpose of use.
2. Measurement Accuracy
Measurement accuracy is not necessarily important for pressure gauges, depending on the purpose or application. On the other hand, in advanced industrial applications or in demanding environments, high accuracy may be required, so it is necessary to clarify what the measured values will be used for.
3. Display
Make sure that the measured values are designed to be easily readable. The key is to choose a display with a clear digital readout that makes it easy to read the units and numerical values. A backlit display is also useful for use in dark environments.
4. Operability and Ease of Use
It is important to select a digital pressure gauge that has an intuitive operation with easy-to-understand button layout and menu structure. Preferably one with a user-friendly interface and easy to set up and read data.
5. Power Supply and Battery Life
Digital pressure gauges require a power supply, and it is important to check the status of power supply options, such as battery operation or AC adapter compatibility, depending on the environment in which they will be used. It is also important to select a product with a long battery life and short recharging time, so it is important to envision what situations you will be using the product.