A segmental wedge flowmeter is a type of differential pressure flow meter used to measure the flow rate of fluids in a pipe. It consists of a segmented wedge-shaped obstruction placed in the flow stream. This obstruction causes a pressure drop across the meter, which is related to the flow rate of the fluid.

Here are the key features and working principles of a segmental wedge flowmeter:

Features:

1. Segmented Wedge Design: The flow meter features a segmented wedge-shaped obstruction that is inserted into the pipe. The shape of the wedge creates a pressure differential across the meter as fluid flows through it.

2. Pressure Taps: Pressure taps are installed upstream and downstream of the segmental wedge to measure the differential pressure generated by the flow obstruction.

3. Material Construction: Segmental wedge flowmeters are typically constructed from materials such as stainless steel, carbon steel, or other corrosion-resistant alloys suitable for the fluid being measured.

Working Principle:

1. Flow Obstruction: As fluid flows through the pipe, it encounters the segmented wedge obstruction placed in the flow path. The segmented shape of the wedge causes the fluid to accelerate and decelerate as it passes through the meter.

2. Pressure Differential: The change in velocity and direction of the fluid flow around the segmented wedge creates a pressure drop across the meter. This pressure drop is proportional to the flow rate of the fluid.

3. Differential Pressure Measurement: Pressure taps located upstream and downstream of the segmental wedge measure the differential pressure across the meter. The magnitude of the pressure drop is related to the flow rate according to the flow meter's calibration.

4. Flow Calculation: The measured differential pressure is used in conjunction with the flow meter's calibration curve or equation to determine the flow rate of the fluid passing through the pipe.

Advantages:

1. Accuracy: Segmental wedge flowmeters can provide accurate flow measurements across a wide range of flow rates and fluid conditions.

2. Wide Rangeability: These flowmeters offer good rangeability, allowing for measurement of both low and high flow rates with the same meter.

3. Low Maintenance: With no moving parts, segmental wedge flowmeters require minimal maintenance and have a long service life.

Disadvantages:

1. Pressure Loss: Like other obstruction-type flow meters, segmental wedge flowmeters can cause a significant pressure drop in the fluid system.

2. Installation Requirements: Proper installation, including sufficient straight pipe lengths upstream and downstream of the meter, is necessary to ensure accurate flow measurement.

Segmental wedge flowmeters are commonly used in industries such as oil and gas, chemical processing, water treatment, and power generation for measuring the flow of liquids, gases, and steam. They are particularly well-suited for applications requiring accurate flow measurement under a wide range of flow rates and fluid conditions.