Current position > Product detail
『Float Flow Meter: Mechanical Tapered Rotameters and Visual Needle Indicators』Related information(v cone flow meter|rotary gas meter|gallon meter|gear meter|metal tube rotameter|glass tube rotameter|nutating disk meter|transit time ultrasonic flow meter|wedge flow meter|pd meters|hydraulic flow meter|ultrasonic water flow meter|water flow meter|air flow meter|magnetic water flow meter|oxygen flow meter|gas flow meter|argon flow meter|air velocity meter|gasoline flow meter|fuel flow meter|ultrasonic water meter|digital water meter|nitrogen flow meter|solid flow meter|Oxygen tank flow meter|digital water flow meter|diesel fuel flow meter|steam flow meter|02 flow meter|compressed air flow meter|oil flow meter|liquid flow meter)
Float Flow Meter: Mechanical Tapered Rotameters and Visual Needle Indicators
A float flow meter, also called a mechanical tapered rotameter, gives you direct flow reading without external power. A visual needle indicator makes the reading clear on a linear scale, often in litres per hour or cubic metres per hour. These meters handle clean liquids and gases like water, air, oil, and chemicals at a low installed cost.
Silver Automation Instruments supplies rugged mechanical rotameters built for local indication only. The flow tube has a tapered bore. As flow increases, the float rises. A needle indicator couples to the float magnetically or via a direct mechanical linkage. The pointer moves across a printed scale. No 4-20 mA loop, no wiring. If you only need to see flow on the pipe, this is the simplest solution.
We have seen these meters in many real installations. A water treatment plant in the Philippines uses DN25 rotameters to monitor reverse osmosis brine flow. A chemical blending facility in South Africa uses PVDF body rotameters for diluted acids at ambient temperature. Last year a customer in Vietnam asked us for a rotameter to measure lube oil at 50 °C on a ship. We supplied a DN20 metal tube unit with a needle indicator calibrated in L/min. It still runs without any trouble.
Mechanical Tapered Rotameter Construction
The meter body comes in SS304, SS316, PVC, or PVDF. Wetted parts exclude electronics, so material compatibility is the key. Glass tubes suit low pressure up to 10 bar and temperatures up to 100 °C. Metal tubes can handle 40 bar and 200 °C for some designs. Float materials include SS316, PTFE, or Hastelloy for corrosive fluids. For higher viscosity fluids, a special float shape keeps reading stable.
Visual Needle Indicator Features
The visual needle indicator is the readout part. It uses a magnetically coupled pointer that stays outside the process fluid. Engineers prefer this for clear reading at a glance, especially in poor lighting near skids. The scale can be custom printed in engineering units such as L/h, m3/h, kg/h, or GPM. Some models include a mechanical switching contact for high/low alarm, but the base indicator remains purely mechanical. In practice, most users only need a quick visual confirmation of flow.
Why Choose a Mechanical Rotameter Over Digital
Here is the thing. You avoid wiring, loop power, and explosion proof certifications. Total in
_600x400.jpg)
Common Applications
Cooling water circuits in steel mills, nitrogen purge lines in oil refineries, diesel fuel flow in generator sets, and detergent dosing in food plants all use these meters. They also fit desalination brine lines, compressed air headers, and lube oil systems on ships. Because the meter has no electronics, it works in high humidity areas like Southeast Asia without drift.
Price and Selection Criteria
Pricing depends on body material, size, and any alarm switch option. A basic DN15 PVC rotameter for water costs less than a metal tube unit at DN50 with high temperature seals. Send us your pressure (bar), temperature (°C), pipe size (DN), and flow range. Also tell us the fluid name and viscosity if it is not water. We will respond with a specific quotation and lead time. Contact Silver Automation Instruments: Tel: +86-25-68650347, Whatsapp: +86-25-52155837, WeChat: +86 15365082610.
Frequently Asked Questions
Q: What fluids can a float flow meter measure?
Clean liquids and gases that do not coat the float or tube. Avoid slurries or dirty fluids that cause sticking or clog the tapered tube.
Q: Does the visual needle indicator show totalized flow?
No, it only shows instantaneous flow rate. For batch control or total volume you need a separate totalizer or an electronic converter.
Q: Can I use a rotameter in a horizontal pipe?
Float flow meters require vertical mounting with flow upward. Horizontal installation will cause measurement errors and float sticking.
Q: What is the maximum pressure rating for a glass tube rotameter?
Typically 10 bar at 20 °C, but always confirm with the supplier. Metal tube designs easily reach 40 bar or more.
Q: How do I order a float flow meter from Silver Instruments?
Provide fluid details, pressure, temperature, pipe size, flow range, and required connection type. We will prepare a datasheet and quote. Use the Tel or WhatsApp above for fast support.