Overview

The porous balanced flowmeter consists of a porous orifice plate throttling device, a differential pressure transmitter, and a display instrument.

The porous balanced flowmeter is a flow measuring instrument based on the principle of differential pressure. The structure of this flowmeter combines the orifice plate with a rectifier, opening several holes on a plate based on certain calculations and functional relationships. By measuring the differential pressure on both sides of the orifice plate, flow measurement is achieved. The porous orifice plate throttling device works in conjunction with the differential pressure transmitter and display instrument to measure, display, and accumulate flow.

Due to its special structure, the porous balanced flowmeter is particularly suitable for flow measurement in situations where the straight pipe section is short, the medium is relatively dirty, the flow rate is low, and there are certain requirements for pressure loss. Additionally, its simple structure and ease of installation and maintenance allow for widespread application in industries such as metallurgy, power generation, chemical engineering, textiles, light industry, and heating.

Working Principle

The porous balanced flowmeter is developed based on the orifice plate and operates on the same principle as standard throttling devices, which is based on Bernoulli's equation and the fluid continuity equation. When fluid flows through the porous balanced flowmeter, its velocity increases, resulting in a decrease in static pressure. This creates a static pressure difference before and after the porous orifice plate, allowing for flow measurement through differential pressure measurement (see Figure 1). The square root of the differential pressure is proportional to the flow rate.

The relationship between mass flow rate and differential pressure is determined by the following formula:

qm——mass flow rate kg/s

C——discharge coefficient dimensionless
β——equivalent diameter ratio of porous orifice plate d/D dimensionless
d——equivalent diameter of porous orifice plate under working conditions m
D——inner diameter of pipeline under working conditions m
ε——expandability coefficient dimensionless
Δp——differential pressure Pa
ρ——density of fluid kg/m³
Product Features³

Due to its geometric structure similar to that of a rectifier, the porous balanced flowmeter retains some advantages of orifice plates while also incorporating many benefits of rectifiers. In practical applications, it has the following characteristics:

1. Unique self-rectifying structural design with uniformly symmetrical distribution of throttling holes greatly reduces requirements for straight pipe sections before and after.

2. High measurement accuracy and good repeatability;

3. The porous structure enhances the instrument's resistance to dirt and makes it less prone to clogging;

4. Wide measurement range with low permanent pressure loss, enabling energy conservation and emission reduction;

5. Suitable for measuring bidirectional flow media;

6. Wear-resistant with long-term stability.

Technical Specifications

Applicable Media

'Type

'ZLDP'

'Code'

'Nominal Diameter (mm)'

For pipe diameters greater than 1000mm, it is expressed as 1/10 of the actual pipe diameter.

Schematic diagram

Pipe-type multi-hole balanced flow meter

Flange sandwich type multi-hole balanced flow meter

Welded integrated multi-hole balanced flow meter

Flange pressure-taking integrated multi-hole balanced flow meter

Insulated jacket type integrated multi-hole balanced flow meter