Company Profile

In Line Flow Meters: Threaded High-Pressure Brass and Steel Fluid Loop Components

Quick Answer: We supply inline flow meters with threaded brass or steel fluid loop components for pressures up to 400 bar. These meters cover DN6 to DN25 pipe sizes and give you pulse, 4-20 mA, or HART outputs. They suit fuel oil, hydraulic test loops, chemical dosing, and cooling water circuits.

Silver Automation Instruments builds these inline meters for engineers who need a compact device that mounts directly into a threaded pipe run. No welding is required. The meter body is available in C360 brass for non-corrosive liquids and 316L stainless steel for aggressive fluids or higher temperatures. The threaded connections can be G1/4, G3/8, G1/2, NPT1/2, NPT3/4, or M14x1.5 depending on the line size.

We have seen these meters used on engine test benches in Vietnam and on desalination skids in Oman. A paint manufacturer in Brazil uses one DN12 steel meter on a solvent dosing line. One customer in Malaysia runs a DN15 brass oval gear meter on a diesel fuel return line at 12 bar.

What Threaded High-Pressure Inline Meters Do We Offer?

The main models are oval gear positive displacement meters and turbine meters. The oval gear meter works well with viscous fluids from 1 to 1000 cP. It gives an accuracy of 0.5% of reading on diesel, lube oil, and heating oil. The turbine meter fits low-viscosity fluids like water and light solvents. Accuracy for the turbine type is 1.0% of reading. Both types can be built with threaded brass or steel bodies.

For a DN15 brass meter with NPT1/2 threads, we usually recommend the SI-OG-15-THP. The pressure rating is 250 bar for brass and 400 bar for the 316L steel version. The flow range starts at 0.05 L/min and goes up to 5 L/min depending on viscosity. For water lines from DN20 to DN25, the SI-TF-20-THP turbine model is a better match.

Brass or Steel: How to Choose

Brass is the lower cost option for diesel, fuel oil, kerosene, and clean water. It machines well and resists corrosion in most non-seawater systems. Do not use brass with seawater, ammonia, or hot condensate. Steel is the better choice for seawater, glycol, hydraulic oils above 120°C, and any fluid with a risk of dezincification. If you are unsure, send us the fluid name and temperature. We will specify the wetted parts.

Here is the thing: pressure rating depends on the seal as much as the body. A brass body with Viton seals has a lower temperature limit than a 316L steel body with PTFE seals. The threaded connection style also matters. NPT threads are common in North America and the Middle East. G threads are common in Europe, Southeast Asia, and Australia. A high-pressure loop with G1/2 threads is not the same as one with NPT1/2. We machine both types, so you do not need an adapter fitting.

Output and Wiring Options

Standard outputs include pulse, 4-20 mA, and 4-20 mA HART. Pulse output is used by PLC counters and fuel consumption loggers. The 4-20 mA signal fits most process control panels. HART gives you remote access to flow rate, total, and diagnostic status without opening the cabinet. Most meters can also include a PT100 temperature sensor for mass flow compensation when the fluid density changes with temperature.

For hazardous areas, we can build the meter with an ATEX Zone 1 approved sensor housing. The display can be local or remote. In a compact thread-mounted meter, the display is often omitted to save space. The electronics then sit in a small aluminium head or in a remote panel.

Where These Meters Are Used

Inline threaded flow meters fit fluid loops where space is tight and the pipe is already threaded. Common industries include oil and gas, water treatment, chemical processing, food and beverage, and marine auxiliaries.

We sell to distributors and end users in the Philippines, Indonesia, Saudi Arabia, Me