Mass Flow Control Units for Ultra Precise Laboratory Gas Mixing and Dosing Hardware

Quick Answer: Silver Automation Instruments supplies mass flow control units for laboratory gas mixing and dosing hardware. The MFC units control gas flow directly in sccm or slm with an accuracy of plus or minus 1 percent of full scale. Send your gas type, flow range in sccm or slm, and fitting size to get a quote from our engineers.

What a Mass Flow Control Unit Does in a Lab

A mass flow control unit measures gas mass flow and adjusts a built in valve to hold the setpoint. The sensor is thermal. The valve is electromagnetic or piezo driven. A closed loop electronics board reads the sensor signal and commands the valve. The control loop runs many times per second. Most engineers skip this part but the control loop keeps the flow accurate even when inlet pressure drifts.

In laboratory gas mixing, one MFC unit feeds one gas line. Several MFC units feed a common mixing chamber. A PLC or a laptop sends the flow setpoints to each unit. The MFC units then deliver fixed gas ratios. Common gases are nitrogen, argon, oxygen, carbon dioxide, methane, hydrogen, and dry air. Standard flow ranges run from 0 to 10 sccm up to 0 to 20 slm.

Do not confuse these MFC units with inline flow meters sized DN15 or DN25. Lab gas dosing uses small tube fittings like 1/8 inch NPT or 1/4 inch VCR. Response time is under 1 second. Repeatability is plus or minus 0.2 percent of full scale. Warm up time is less than 5 minutes. These are values we see on customer test benches in Vietnam, Indonesia, and Malaysia.

Why Silver Instruments MFC Units Fit Lab Gas Mixing Rigs

Silver Instruments mass flow control units use 316L stainless steel wetted parts. Wetted seals are Viton, Kalrez, or EPDM. Seal choice matters when a lab works with aggressive gases or high purity gases. A wrong seal swells or leaks. We have seen this on customer sites many times in humid coastal areas.

The MFC units accept a setpoint from a 0 to 5 VDC signal, a 4 to 20 mA signal, or RS485 Modbus. Power supply is 24 VDC. Output options include 0 to 5 VDC, 4 to 20 mA, and RS485 Modbus. Fittings are 1/4 inch VCR, 1/8 inch NPT, or 6 mm Swagelok. These fittings cover most laboratory gas panels in Southeast Asia and Australia.

Because the body is compact, one DIN rail or panel can hold multiple MFC units. A gas mixing skid for catalyst testing may use four or six units side by side. The units do not need a separate flow computer. The setpoint can come from a simple potentiometer or a PLC analog output.

Key Parameters for Ultra Precise Gas Dosing

Send us the gas type first. The thermal sensor is calibrated for a specific gas. Silver Instruments calibrates standard units with nitrogen at 20 degrees Celsius. For other gases, we apply correction factors. Some gases need a dedicated calibration. Hydrogen and helium have different thermal conductivity. Carbon dioxide and argon also differ from nitrogen. A wrong correction factor shifts the flow reading by 5 to 15 percent.

Flow range is next. Pick a range that covers your actual dosing rate. Most lab processes operate best between 10 percent and 90 percent of full scale. A 0 to 100 sccm MFC unit is not ideal for a 2 sccm dosing task. In practice, the low end accuracy drops near zero flow. A 0 to 10 sccm or 0 to 20 sccm range works better for small flows.

Inlet pressure and outlet pressure matter too. Standard MFC units need a differential pressure across the valve. A typical inlet pressure is 2 to 5 bar gauge. Outlet pressure can be atmospheric or up to 1 bar gauge depending on the back pressure. High pressure options go up to 10 bar inlet. Low pressure drop versions are available for vacuum outlet or near atmospheric mixing chambers.

Signal output is the last point. Many labs use 0 to 5 VDC because their data loggers accept that signal. Industrial plants often request 4 to 20 mA with HART. For multiple MFC units on one bus, RS485 Modbus cuts wiring. Specify the fitting type and seal material in the RFQ.

Common Applications and Customer Sites

A university chemistry lab in Malaysia blends argon and hydrogen at 50 sccm each for catalyst testing. The lab uses two Silver Instruments MFC units with 0 to 100 sccm ranges and 1/4 inch VCR fittings. The gas mixture goes into a tube furnace. The lab reports stable flow within plus or minus 0.5 sccm over a six hour run.

A food packaging plant in Vietnam mixes nitrogen and carbon dioxide for modified atmosphere packaging. The plant uses three MFC units with ranges of 0 to 5 slm, 0 to 10 slm, and 0 to 20 slm. The units receive setpoints from a small PLC on the packaging line. The gas blend keeps oxygen out of snack packs.

A pharmaceutical lab in Saudi Arabia doses oxygen into benchtop bioreactors at 0 to 1 slm. The lab chose Kalrez seals and 316L stainless steel bodies to handle clean steam sanitation. The MFC units sit inside a stainless steel panel with a 0 to 5 VDC signal output.

A wastewater research station in Chile feeds methane and air into a lab scale anaerobic digester. The methane flow is 0 to 50 sccm. The air flow is 0 to 500 sccm. The station logs flow data over RS485 Modbus. The digester setup runs 24 hours a day during a two month trial.

An aquaculture research center in Australia controls dissolved oxygen in small test tanks. The center uses an MFC unit for air at 0 to 2 slm. The unit ramps flow up and down based on a dissolved oxygen probe signal. No mass flow controller failure was reported after 18 months of operation.

Pricing and Lead Time

Price depends on flow range, seal material, signal output, and fitting type. A standard Silver Instruments MFC unit with a 0 to 500 sccm range, 316L body, Viton seals, 4 to 20 mA output, and 1/4 inch VCR fittings starts from 480 USD. A unit with Kalrez seals and RS485 Modbus costs more. A 0 to 20 slm range costs more than a 0 to 500 sccm range because the sensor and valve are larger.

Standard models ship in 7 to 12 days. Custom ranges or special gas calibrations take 15 to 20 days. We ship by DHL, FedEx, or TNT to Australia, Vietnam, Indonesia, Malaysia, Saudi Arabia, Chile, Nigeria, and other countries. Send your gas type, flow range in sccm or slm, inlet pressure in bar, outlet pressure, fitting type, and signal output to get a formal quote.

Contact Silver Automation Instruments for mass flow control units and lab gas mixing hardware. Tel: +86-25-68650347. Whatsapp: +86-25-52155837. WeChat: +86 15365082610.

FAQ

Can a mass flow control unit handle corrosive gases? Wetted parts are 316L stainless steel. Seals are available in Viton, EPDM, or Kalrez. For gases like hydrogen chloride or sulfur dioxide, choose Kalrez seals. Tell us the gas name and concentration before ordering.

What flow range should I order for laboratory gas mixing? Pick the smallest range that covers your maximum flow. A 0 to 100 sccm range works for many catalyst and reactor tests. A 0 to 5 slm range is common for food packaging gas blends. Avoid using a range that is ten times larger than your actual flow.

Does the MFC unit include a display? Standard units have no local display. You can read the flow signal through 0 to 5 VDC, 4 to 20 mA, or RS485 Modbus. A small local display module is an option for labs that want a direct reading.

Can I use one MFC unit for multiple gas types? You can but the calibration must match the gas. A unit calibrated for nitrogen will not read carbon dioxide correctly without a correction factor. Silver Instruments applies gas correction factors at the factory. For high accuracy, order a dedicated gas calibration.

What is the minimum order quantity for mass flow control units? One unit is enough for a trial order. Most lab customers start with one to three MFC units. For gas mixing skids with four or more channels, we offer a package price.

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