QINWEIYB · Xi'an Qinwei Instrument Factory

Compact Threaded Electromagnetic Flowmeter for DN6–DN50 OEM and Dosing Lines

Small lines are where flow goes wrong quietly. A dosing pump that over-feeds an additive, a liquid-cooling loop nobody actually measures, an OEM unit shipped without a flowmeter because there was no room — each one leaks money and control every day. This compact threaded electromagnetic flowmeter replaces bulky flanged bodies with standard BSP or NPT threaded ends, so it screws straight into DN6–DN50 pipework. It keeps Faraday-law accuracy at ±0.5% with no moving parts, making it a natural fit for pure-water, chemical-dosing and liquid-cooling equipment. It is one of four connection styles in the QINWEIYB compact electromagnetic flowmeter family.

Why Do Small OEM, Dosing and Cooling Lines Need a Compact Threaded Meter?

On small-bore pipework the pipe itself, not the process, becomes the constraint. A flanged meter needs two flange faces, gaskets and bolting on lines that may be only DN15 or DN25 wide — adding cost, weight and leak paths to equipment that was never designed for it. Many OEM builders therefore leave the small line unmetered, losing the data they need for dosing control, energy accounting and warranty analysis.

A threaded meter screws into the line with a spanner and almost no extra hardware. It fits the pipework that exists, keeps the loop compact and delivers dependable data without a redesign. The table below compares four small-line conditions, the pain each creates and how the threaded design answers it.

Working Principle: Faraday's Law Applied to Small Threaded Lines

The meter uses Faraday's law of electromagnetic induction. A compact coil pair generates a magnetic field across a lined measuring tube; as conductive liquid flows through it, a small voltage appears across two electrodes in the tube wall. That voltage is proportional to the average velocity, so flow rate is calculated from the tube's known bore — even on the very small diameters that threaded connections serve.

There is nothing inside the bore to block or wear, so the sensing stays accurate on low and pulsing flows where mechanical meters struggle. Pressure drop is negligible and the reading is largely independent of pressure, temperature, density and viscosity within the rating. The threaded body simply adapts that principle to DN6–DN50 pipework using standard BSP or NPT ends, so the meter becomes part of the machine rather than an add-on.

Structural Advantages of the Compact Threaded Design

• BSP or NPT threaded ends: external or internal threads screw directly into standard small-bore pipework.
• Very compact body: short overall length suits OEM equipment, dosing skids and liquid-cooling loops.
• Fewer fittings, fewer leaks: a single threaded seal replaces the flange, gasket and bolt set of a conventional meter.
• Fast installation: a spanner and thread sealant are all that is needed to fit the meter.
• Flexible wetted materials: PTFE, F46 or rubber liners with 316L, Hastelloy C or titanium electrodes.
• Sealed and readable: IP65 / IP67 housing with an LCD display for local flow checks.

Typical Application Cases

The QWDC-TH120 threaded flowmeter serves OEM machine builders, chemical-dosing system integrators and cooling-equipment suppliers working in the DN6–DN50 range.

Key Product Advantages

• Threaded BSP or NPT ends: fits standard small-bore pipework with minimal hardware.
• Ultra-compact body: designed for OEM machines, dosing skids and tight cooling loops.
• Leak-tight installation: one threaded seal in place of multiple flange interfaces.
• Fast to fit and service: installed and removed with ordinary hand tools.
• Accurate and stable: ±0.5% of reading with ±0.1% repeatability.
• No moving parts: full-bore sensing resists clogging on low, pulsing flows.
• Material flexibility: PTFE, F46 or rubber liners with 316L, Hastelloy C or titanium electrodes.
• Clear local display: LCD indication with 4-20mA, pulse or RS485 output options.

Technical Specifications

Model QWDC-TH120 | Brand QINWEIYB | Connection thread BSP / NPT | Output 4-20mA / pulse / RS485 | Media pure water, chemicals, coolant | Display LCD | Origin China

Frequently Asked Questions

1. What is a threaded electromagnetic flowmeter?

A threaded electromagnetic flowmeter is a compact sensor whose inlet and outlet are finished with standard screw threads — commonly BSP or NPT — instead of flanges. It screws directly into small-bore pipework, typically from DN6 to DN50, using ordinary hand tools and a thread sealant. Like all electromagnetic meters it works on Faraday's law of induction, so it has no moving parts and adds almost no pressure drop. The threaded format is chosen where lines are small, space is limited and installation must be quick: OEM machines, chemical-dosing systems, liquid-cooling units and pure-water skids. It delivers the same measurement principle as larger meters in a body small enough to disappear into the machine.

2. Which thread standards are available, BSP or NPT?

Both are offered. BSP (British Standard Pipe) threads are common in Europe, Asia and many process markets, while NPT (National Pipe Taper) threads are standard in North America. The meter can be supplied with either external or internal threads to match your mating fitting. Choosing the correct standard matters because the two are not interchangeable and a mismatch will leak under pressure. The thread size is normally quoted against the pipe diameter, for example 1/2 inch BSP or 1 inch NPT, and must match the process connection on the line. When ordering, state the exact thread type, size and gender so the meter is built to fit first time.

3. What pipe sizes and media can this threaded meter handle?

The threaded model covers DN6 to DN50, the small-bore range where screw connections are practical. It measures any sufficiently conductive liquid, including pure and process water, chemical additive solutions, water-glycol coolant and many light process liquids. The medium must have enough conductivity to generate a measurable signal, typically a few microsiemens per centimetre and above; deionised water, oils and most solvents fall outside this range and are not suitable. For aggressive chemicals choose a PTFE or F46 liner with a Hastelloy C or titanium electrode, and for standard cooling or water loops a rubber liner with a 316L electrode is usually sufficient.

4. How accurate is the threaded electromagnetic flowmeter?

It is rated at ±0.5% of reading with ±0.1% repeatability, which is ample for dosing control, cooling-loop monitoring and OEM performance data. Accuracy in practice also depends on correct installation: keep the tube full, allow reasonable straight pipe upstream and downstream of the meter, and avoid fitting it immediately after a pump, elbow or partly closed valve. On very small diameters, following the recommended straight lengths matters even more, because disturbances occupy a larger share of the pipe. Used within its intended scope, the threaded meter delivers repeatable, dependable readings that support closed-loop control and accurate sub-metering on small lines.

5. Is the meter affected by pressure drop or clogging?

No. Because the sensing electrodes sit flush in the bore and there are no internal moving parts, the meter adds virtually no pressure drop and has nothing that can clog or jam. This is a major advantage over turbine, paddle-wheel or positive-displacement meters on small lines, where low and pulsing flows cause moving parts to wear or stick. The full-bore electromagnetic design handles dirty water, light solids and chemical additives without the maintenance burden of mechanical sensing. For the very smallest diameters, simply ensure the medium stays conductive and full, and the meter will continue to read reliably over a long service life.

6. What power supply and outputs are available?

The meter runs on 24 VDC or 220 VAC, so it suits both plant panels and standard mains supply. Outputs include 4-20mA analogue, pulse and RS485 digital communication, allowing the signal to feed a PLC, controller, data logger or SCADA system. A local LCD display shows flow in real time for commissioning and routine checks. Confirm the available supply voltage and the signal your control system needs before ordering, so the unit is configured correctly at the factory. Our engineers can advise on matching the power supply and output options to your equipment or process-control setup.

Why Choose Our Electromagnetic Flowmeter?

QINWEIYB builds this threaded electromagnetic flowmeter for OEM machines and small process lines where space, speed and reliability all matter. It keeps the trusted electromagnetic principle while making the meter small enough to screw straight into DN6–DN50 pipework.

You buy directly from the factory for thread selection, liner and electrode advice and spare parts, and every meter is configured with a wetted-material combination matched to your medium before it ships.