『Dial Flow Meter: Visual Thorpe Tube Needle Valve Gas Scale Regulators』Related information(clamp on meter|electromagnetic meter|venturi meterrotameter|orifice meter|ultrasonic flow meter|mass flow meter|coriolis mass flow meter|coriolis flow meter|magnetic flow meter|magmeter flow meter|magflow flow meter|mag meter flow meter|electromagnetic flow meter|vortex flow meter|turbine flow meter|thermal mass flow meter|thermal flow meter|rotameter flow meter)
Dial Flow Meter: Visual Thorpe Tube Needle Valve Gas Scale Regulators
Quick Answer
As a flow meter manufacturer, Silver Automation Instruments supplies dial flow meters with visual Thorpe tube and needle valve gas scale regulators for low gas flow from 0.05 L/min to 100 L/min. These units give direct reading and manual control for nitrogen, argon, oxygen, CO2 and biogas lines. Send your gas type, pressure in bar, temperature in °C, pipe size and required flow range for a quote.
What Is a Visual Thorpe Tube Dial Flow Meter
This type of meter combines a vertical tapered glass or acrylic tube, a float, a calibrated dial scale and a needle valve. Gas enters the bottom, lifts the float, and you read the flow rate at the widest point of the float. That is the standard Thorpe tube method. Because the tube is clear, you see the float position at any time. This helps in gas purging, blanketing, lab gas supply and pilot plant lines.
In practice, most engineers skip electronic transmitters for these low flow jobs. A visual meter costs less to install, needs no power, and lasts for years with clean dry gas.
Needle Valve Gas Scale Regulator: What Changes
The needle valve sets the gas flow manually. A fine thread gives smooth adjustment from very low to full scale. The dial scale is printed on the tube or mounted beside it. Some units have a dual scale, such as L/min and SCFH. We have seen customers in Indonesia use the dual scale for nitrogen blanketing on small storage tanks.
This combination works well when the supply pressure stays within a known band. Typical inlet pressure ranges are 0.1 to 0.6 MPa depending on the tube body. If the pressure moves more than 20 percent, you will see the float shift.
Key Specifications and Model Pairing
Silver Instruments recommends Model DFM-TT for general gas flow. Standard ranges include 0.05 to 0.5 L/min, 0.1 to 1 L/min, 1 to 10 L/min and 10 to 100 L/min for air equivalent. Accuracy is plus or minus 4 percent of full scale. This is enough for purge and seal gas, not for custody transfer.
Standard connections are 1/8 inch NPT, 1/4 inch NPT or 6 mm and 8 mm tube fittings. Body options include acrylic for noncorrosive gas and glass for solvents or higher chemical resistance. Wetted parts use stainless steel 316, PTFE and borosilicate glass. Maximum operating temperature is 60 °C. Maximum pressure for acrylic is 0.6 MPa. For glass, it is 0.4 MPa.
A paint manufacturer in Vietnam ordered 30 units last year for nitrogen purge lines on solvent drums. They needed a simple dial flow meter with a visual Thorpe tube and needle valve gas scale regulator because the line pressure stays at 1.5 bar. The flow range was 0.5 to 5 L/min. The order shipped from China in 12 days.
Common Application Scenarios We See
Customers in the Middle East use these meters for gas blanketing on ch
For a DN15 or DN20 process tap, use a 1/4 inch NPT adapter. This avoids long tube runs that lag the reading.
Installation and Maintenance Notes
Install the tube in a vertical position. Read the float at eye level. The needle valve can sit upstream or downstream of the tube depending on model. Upstream control is standard for low flow stability. Keep the gas clean. A 5 micron filter before the inlet is enough for most sites. For sticky gas or liquids mixed in the line, do not use this meter.
Because the meter has no electronics, it can be used in gas areas where a passive device is accepted. If your site needs ATEX Zone 1 certification, ask us first.
Cleaning is simple. You can remove the outer shield and wipe the acrylic body with a soft cloth. For glass tubes, use warm soapy water and dry fully. Do not use acetone on acrylic. That cracks the body.
How to Get a Quote from Silver Instruments
Send us your gas type, flow range, inlet pressure in bar, temperature in °C, connection size and whether you need a needle valve on the inlet or outlet. We will reply with a price, lead time and shipping cost. Tel: +86-25-68650347. Whatsapp: +86-25-52155837. WeChat: +86 15365082610. You can also search Silver Automation Instruments on flow-meter.com.au.
FAQ
Here are the five most common questions from our customers about these dial flow meters.
1. What is the difference between a dial flow meter and a rotameter?
A dial flow meter with a Thorpe tube is a type of rotameter. The main difference is the direct reading dial scale and the built-in needle valve. A standard rotameter often has no valve or uses a separate one.
2. Can I use this meter for oxygen service?
Yes. You can order an oxygen cleaned version. Specify oxygen service when you send the inquiry. This affects degreasing and packaging.
3. What gas flow range should I select?
Pick a range where your normal flow sits between 30 and 80 percent of full scale. For example, if your nitrogen flow is 3 L/min, choose a 1 to 5 L/min or 1 to 10 L/min meter. Do not operate below 10 percent of full scale because accuracy drops.
4. Can I use this for high pressure gas?
The standard body is rated to 0.6 MPa for acrylic and 0.4 MPa for glass. For higher pressure, ask us about stainless steel tube options. That costs more but handles 10 bar and above.
5. How do I read the float?
Use the widest point of the float as the reading line. For a ball float, read the center of the ball. Keep your eye level with the float to avoid parallax error.
Hot Blog
Related AD
