Flow Meters › Target Flow Meters › Insertion Target Flow Meter
Insertion Target Flow Meter
An insertion target flow meter puts a target disc on a probe into a large line through a single boss and measures the drag force the fluid pushes on it. A force sensor turns that drag into a flow reading. With no pressure taps to plug and no moving parts, it meters DN80 to DN5000 pipes that are too large or costly for a full-bore meter, and handles viscous, dirty, corrosive, and extreme-temperature service.
- Principle: Drag force on a target, force sensor
- Best for: Low flow, viscous, dirty, and extreme temperature
- Temperature: -196 C to +500 C
- Pressure: Up to 42 MPa
- Accuracy: 0.5% to 1.5% by connection
- Output: 4-20 mA, pulse, RS485 or HART
Overview
An insertion target flow meter measures flow on large lines where a full-bore meter is impractical or too costly. A target disc on a probe is inserted through a boss in the pipe wall and centered in the stream; the drag force on the disc rises with density and the square of velocity, and a chip-level force sensor reads it as flow. Because the probe enters through one tapping, it fits DN80 to DN5000 lines and can be mounted on an isolation valve for hot-tap installation without shutting the line down.
The insertion build keeps the strengths of the target principle: no pressure taps to plug, no moving parts to wear, and a fully welded sensor that handles viscous, dirty, corrosive, condensing, and extreme-temperature service. It trades a little accuracy, 1.5% of full scale against 0.5% for a full-bore flanged unit, for the ability to meter very large pipes at low installed cost.
Features
Everything here follows from one idea: read flow from the drag force on a target, instead of a pressure tap or a moving rotor.
Reads low flow
It senses the drag force directly, so it stays accurate where the pressure drop across an orifice is too small to read.
Chip-level force sensor
A chip-level force sensor with an anti-overload structure gives high sensitivity and accuracy to 0.5%.
Extreme temperature and pressure
Rated from -196 C to 500 C and up to 42 MPa, for cryogenic, high-temperature, and high-pressure lines.
Handles difficult fluids
No pressure taps to plug, so it reads viscous, dirty, and corrosive liquid, gas, and steam that foul an orifice.
Welded, no moving parts
A solid target and sensor, with no rotor to wear, and a fully welded body with no leak paths.
Standard outputs
4-20 mA, a voltage or pulse signal, and optional RS485, for a display, a PLC, or a DCS.
Working principle
The target is the sensor. A disc of a chosen size sits in the flow on a rod, facing upstream. Moving fluid exerts a drag force on the disc that rises with the fluid density and the square of the velocity, so the force is a direct measure of flow. The rod carries that force to a force sensor outside the flow, which reads the tiny deflection and converts it to a flow rate. Changing the disc size changes the range, which is how one body covers different flows.
Because the reading comes from force rather than a pressure tap, there are no small impulse lines to plug, and the meter resolves low flows that an orifice cannot. The target and rod are the only parts in the stream, so on dirty or corrosive service the whole wetted assembly can be made of one resistant alloy and fully welded.
Technical specifications
| Parameter | Specification |
|---|---|
| Measurement principle | Drag force on an insertion target; force rises with density and the square of velocity, read as flow |
| Sensor | Chip-level force sensor with an anti-overload structure |
| Accuracy | 1.5% of full scale (insertion) |
| Repeatability | 0.05% to 0.08% |
| Turndown | 1:5 for liquid; up to 1:10 for gas and steam |
| Nominal diameter | DN80 to DN5000 (insertion probe) |
| Mounting | Insertion probe through a flanged or threaded boss; target disc centered in the line; hot-tap on isolation valve available |
| Process temperature | -196 C to +500 C across low, normal, and high-temperature builds |
| Working pressure | 0.6 to 42 MPa |
| Media | Liquid (including high viscosity), gas, and steam; corrosive and dirty service |
| Materials | Carbon steel or stainless tube; 316 stainless, Hastelloy, or titanium wetted parts; other materials on request |
| Output | Local display; 4-20 mA (two- or four-wire); pulse; 0-5 V; RS485 or RS232; HART |
| Lowest velocity | 0.08 m/s |
| Pressure loss | About half that of a standard orifice plate |
| Compensation | Optional integrated temperature and pressure compensation for direct mass or standard-volume output |
| Power | Built-in 3.6 V lithium battery or external 24 VDC |
| Explosion-proof | Intrinsically safe (Exia IIC T4) or flameproof (Exd IIC T6 Gb) |
| Protection | IP65 or IP67 |
| Moving parts | None; only the target and the force sensor |
Insertion or full-bore
Both builds use the same drag-force target and force sensor; the choice is about pipe size, accuracy, and installation. For a full-bore flanged, wafer, or clamp meter on lines up to DN500, see the target flow meter.
| Build | When to choose it |
|---|---|
| Insertion (this page) | Large lines DN80 to DN5000; lowest installed cost; hot-tap on a valve; 1.5% of full scale |
| Full-bore flanged, wafer, or clamp | Lines up to DN500; best accuracy at 0.5%; a complete pipe-section meter |
Applications
Insertion target flow meters suit large-diameter lines and difficult media across heavy industry:
- Cooling-water and circulating-water headers in power plants and steel mills
- Crude, heavy oil, and residual oil transfer on large trunk lines
- Flue gas, process gas, and compressed air on wide ducts
- Slurry, paste, and sediment-bearing flows in mineral processing
- Corrosive and condensing service where pressure-tap meters plug
Application example
Challenge: A steel mill needed flow on a DN800 cooling-water header that could not be shut down for a full-bore meter.
Solution: An insertion target probe was hot-tapped onto an existing isolation valve and centered in the line, with 4-20 mA to the plant control system.
Result: The header was metered without an outage, and the fully welded target shrugged off the scale and suspended solids that had fouled an earlier sensor.
Related products
Target Flow MeterFull-bore flanged, wafer, and clamp builds to 0.5% for lines up to DN500.
Insertion Vortex Flow MeterInsertion vortex probe for clean gas, steam, and water on large pipes.
Browse all target flow meters →
FAQ
What is an insertion target flow meter?
It is a drag-force flow meter built as an insertion probe. A target disc on the end of the probe sits in the flowing stream; the force the fluid exerts on the disc is measured by a force sensor and converted to flow. The insertion form lets one probe meter very large pipes through a single tapping.
How is it installed on a large pipe?
The probe is inserted through a flanged or threaded boss welded to the pipe and centered in the line. With an isolation valve fitted, it can be hot-tapped and removed under pressure, so installation and service do not require a shutdown.
How accurate is an insertion target flow meter?
An insertion build reads about 1.5% of full scale, against 0.5% for a full-bore flanged target. The insertion form trades some accuracy for the ability to meter large lines at low cost; for the tightest accuracy on lines up to DN500, use a full-bore target flow meter.
Insertion target or insertion magnetic flow meter?
An insertion magnetic meter is the better choice for clean, conductive liquids such as water. An insertion target flow meter is preferred for non-conductive, viscous, dirty, condensing, or extreme-temperature media, and for gas and steam, where a magnetic meter cannot read.
Request a quote
Send us the fluid, the line size, the flow range, and the pressure and temperature, and we size the target flow meter and set the target.