Insertion Vortex Flow Meter

Basic Components

Probe Section: This is the component that is inserted into the pipeline, containing a miniature turbine rotor, support bearings, and sensors (such as magnetic induction or photoelectric sensors) for detecting rotor rotation.
Insertion Rod: The rod connecting the probe to the external mounting section.
Sealing Device and Installation Interface: Used to connect to the pipeline and ensure sealing, typically featuring flanges or threads. Many insertion flow meters also include special hot-swap mechanisms, allowing the probe to be installed or removed without stopping the system or depressurizing the pipeline.
External Converter/Display Instrument: Receives signals from the probe, processes them, displays instantaneous and cumulative flow rates, and may provide standard output signals (e.g., 4-20mA).

Working principle

After inserting the probe into the pipeline, the turbine on the probe is located in the fluid flow path. The fluid flows over the turbine blades, driving the turbine to rotate. The sensor inside the probe detects the rotation speed of the turbine and outputs a pulse signal proportional to the rotational speed.

It is important to note that since the probe only measures the fluid velocity at a specific point or area within the pipe cross-section (typically positioned at the pipe center to measure the center flow velocity), rather than the average velocity across the entire cross-section, the flowmeter must estimate the total volume flow rate across the entire pipe cross-section based on the measured local velocity, combined with the pipe’s inner diameter and an assumed model of the fluid velocity distribution within the pipe (e.g., assuming a fixed proportional relationship between center flow velocity and average flow velocity).

Advantages

Primarily used for large-diameter pipes: For pipes with a diameter of DN300 (approximately 12 inches) or larger, manufacturing and installing pipe-type (full-bore) flow meters is costly and inconvenient, making insertion-type flow meters a more economical and practical choice.
Suitable for existing pipe retrofits or situations where production cannot be interrupted: Especially models with hot-swap functionality, which can be installed and maintained without cutting the pipe or stopping production.
Relatively high installation convenience (under large-diameter and no-shutdown requirements).
Cost is typically lower than that of pipe-mounted flow meters of the same diameter.

Limitations

Since it measures local velocity to estimate total flow, its measurement accuracy is generally lower than that of pipe-mounted flow meters of the same type, and it is more susceptible to uneven fluid velocity distribution (e.g., insufficient straight pipe sections, upstream disturbances).

In summary, an insertable turbine flowmeter is an instrument that measures local velocity using a probe inserted into the pipeline to estimate total flow. Its primary advantages lie in installation convenience and cost-effectiveness for large-diameter pipelines or applications where production cannot be interrupted, making it an alternative to pipeline-mounted flowmeters in large-diameter applications, though typically at the expense of some measurement accuracy.

Applications

Large-diameter pipeline measurement:

This is the most typical application. When the pipe diameter is large (typically greater than DN300mm or DN400mm), full-bore pipe-mounted flow meters are expensive and bulky. Insertion turbine flow meters, with their relatively low cost and compact probe structure, become a more economical and practical choice.
Suitable for measuring fluids such as water, clean gases (e.g., natural gas), and oil in large-diameter pipes.

Existing pipeline retrofits or expansions:

In situations where it is inconvenient or not permitted to shut down existing pipelines for extended periods during renovation, insertable turbine flow meters (especially models with hot-swap functionality) can be installed by making openings in the pipeline, significantly reducing downtime and construction complexity.

Cost-sensitive large-diameter pipeline applications:

In scenarios where absolute measurement accuracy is not the highest priority but monitoring of large-diameter pipeline flow is required with limited budget constraints, insertable turbine flow meters are a suitable option.

Certain utility networks:

In large-scale networks such as urban water supply and gas distribution systems, they may be used for regional flow monitoring or segmented metering to manage and balance flow.
In summary, insertable turbine flow meters are primarily used in applications where pipeline diameters are very large, installation conditions are constrained (e.g., shutdown is not feasible), and a certain degree of compromise in accuracy compared to pipeline-mounted flow meters is acceptable.