Differential pressure gauges are instruments used to measure the difference in pressure between two points in a system. They come in various types, each suited for different applications and operating conditions. Here are some of the different types of differential pressure gauges:

1. Bourdon Tube Differential Pressure Gauge: This type of gauge uses two Bourdon tubes connected in parallel to measure the pressure difference between two points. The differential pressure causes one tube to expand while the other contracts, resulting in a deflection of the gauge needle. Bourdon tube differential pressure gauges are commonly used in HVAC systems, filtration systems, and process industries.

2. Diaphragm Differential Pressure Gauge: Diaphragm differential pressure gauges use flexible diaphragms to sense pressure differences. The pressure difference causes deflection in the diaphragm, which is translated into a reading on the gauge. Diaphragm differential pressure gauges are suitable for low-pressure applications and can handle corrosive or viscous fluids.

3. Piston Differential Pressure Gauge: Piston differential pressure gauges use a piston or piston-like mechanism to measure pressure differences. The pressure difference acting on the piston creates a force imbalance, which is indicated on the gauge. Piston differential pressure gauges are often used in industrial applications where high accuracy and reliability are required.

4. Bellows Differential Pressure Gauge: Bellows differential pressure gauges use bellows, which are flexible, accordion-like structures, to measure pressure differences. The bellows expand or contract in response to the pressure difference, causing a corresponding movement of the gauge needle. Bellows differential pressure gauges are suitable for high-pressure and high-temperature applications.

5. Manometer Differential Pressure Gauge: Manometer differential pressure gauges use a column of liquid (such as mercury or water) to measure pressure differences. The difference in the heights of the liquid columns in two connected tubes indicates the pressure difference. Manometer differential pressure gauges are simple and inexpensive but are primarily used for low-pressure applications.

6. Electronic Differential Pressure Gauge: Electronic differential pressure gauges use electronic sensors, such as strain gauges or capacitive sensors, to measure pressure differences. The sensor outputs an electrical signal proportional to the pressure difference, which is then displayed on a digital screen. Electronic differential pressure gauges offer high accuracy, reliability, and versatility and are suitable for various industrial applications.

These are some of the common types of differential pressure gauges available in the market. The choice of gauge depends on factors such as the pressure range, fluid compatibility, accuracy requirements, and environmental conditions of the application.