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『Kofloc Flow Meter Sizing: Ultra-Precision Mass Flow Controllers for Chemical Vapor Deposition Gas Skids』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)
Kofloc Flow Meter Sizing for Chemical Vapor Deposition Gas Skids: Ultra-Precision Mass Flow Controllers
Quick Answer: Kofloc flow meter sizing starts with the gas, full scale flow, inlet pressure, differential pressure, and wetted materials. Most CVD gas panels use 10 sccm to 20 slm mass flow controllers with 316L stainless steel bodies, metal seals, and 4-20 mA HART or RS485 output. Send your gas panel data to Silver Instruments for a quote within one working day.
What Gas and Full Scale Flow Should You Confirm First?
Gas type drives the sizing. Silane, ammonia, dichlorosilane, nitrogen, oxygen, argon, and TEOS vapor are common in CVD gas skids. A thermal mass flow controller calibrated for nitrogen needs a gas correction factor for silane or TEOS. Silver Instruments sets the correction factor at the factory. Here is the thing. Full scale flow is not the pipe size. Most engineers skip this part and oversize the MFC. For low pressure CVD, a 10 sccm MFC is often enough for silane. A 500 sccm MFC fits ammonia. A 5 slm or 20 slm MFC fits nitrogen purge or chamber vent.
What Inlet Pressure and Differential Pressure Are Typical?
On a gas skid, inlet pressure usually sits between 1.0 and 3.0 bar. A Kofloc mass flow controller needs stable differential pressure across the thermal sensor and valve. If the differential pressure is too low, the valve cannot hold setpoint at high flow. If the pressure is too high, the valve fights against the inlet. We have seen this on customer sites in Vietnam and Malaysia. The panel pressure regulator sets the inlet. The chamber or vacuum pump sets the outlet. Share both values. A direct replacement MFC from Silver Instruments matches the same pressure window as the original Kofloc unit.
How Accurate and Fast Should the MFC Be?
Chemical vapor deposition is sensitive to flow drift. For ultra-precision work, setpoint accuracy below plus or minus 0.5 percent is common. Repeatability of plus or minus 0.2 percent or better helps with wafer to wafer uniformity. Response time under 1 second is typical for small MFCs. A slow mass flow controller creates thickness variation in the film. For plasma enhanced CVD, overshoot matters. Silver Instruments thermal mass flow controllers can be tuned for fast response with minimal overshoot on silane, ammonia, and nitrous oxide lines.
What Output Signal and Communication Fit the Gas Skid?
4-20 mA HART is still the standard for many gas skid PLCs. RS485 Modbus RTU is common in newer semiconductor tools. Some systems use 0-5 VDC or 0-10 VDC analog signals. A Kofloc flow meter can be ordered with one or two outputs. Silver Instruments MFCs support 4-20 mA, 0-5 VDC, RS485 Modbus RTU, and HART as options. Confirm the PLC card type before you order. A mixed signal list causes startup delay. Do not assume the replacement has the same pinout. Check the connector and cable wiring diagram.
Which Wetted Materials and Valve Type Are Correct?
For CVD gas skids, 316L stainless steel is the base wetted material. PTFE is acceptable for some low temperature seals. Metal to metal seals are better for toxic or pyrophoric gases like silane
Which Kofloc Models and Silver Instruments Replacements Match?
Kofloc 3660 series appears in many CVD gas panels. For metal seal applications, Kofloc 3760 series or an equivalent Silver Instruments MFC is used. For 10 sccm silane, a low flow 3660 size works. For 500 sccm ammonia, use a mid range full scale. For 20 slm nitrogen, a larger orifice model is needed. Silver Instruments supplies drop in replacements for these Kofloc flow controllers. The replacement keeps the same flow range, voltage, signal, and fitting. No pipe size change is required. For new gas skids, Silver Instruments can size the full MFC set from the process recipe.
A Real Example from a CVD Gas Skid in Malaysia
A customer in Penang runs a plasma CVD tool. The gas lines are silane 50 sccm, ammonia 500 sccm, nitrous oxide 200 sccm, and nitrogen 10 slm. Inlet pressure is 1.8 bar. Chamber pressure is 2 mbar. The original Kofloc flow meters drifted at low flow. Silver Instruments supplied four thermal mass flow controllers with 316L bodies, metal seals, and 4-20 mA HART signals. The full scale ranges matched the existing values. The customer started up in two days. That replacement pattern is common in Malaysia, Vietnam, and Thailand.
How to Order a Silver Instruments Replacement
Send the gas name or mixture, full scale flow in sccm or slm, inlet pressure in bar, outlet pressure in bar, operating temperature in °C, fitting type, and signal output. Include the Kofloc part number if you have it. Silver Instruments will cross reference the model and confirm the interface. Contact Silver Instruments. Tel: +86-25-68650347. Whatsapp: +86-25-52155837. WeChat: +86 15365082610.
FAQ on Kofloc Flow Meter Sizing for CVD Gas Skids
Can I use a nitrogen calibrated MFC for silane? Yes if you apply the correct gas correction factor. Silver Instruments programs the factor before shipment. Confirm the actual gas and full scale.
How do I know the full scale flow from a Kofloc part number? The part number often contains the flow range. If not, check the calibration sheet or nameplate. Silver Instruments can decode common Kofloc part numbers.
What happens if the inlet pressure is too low? The valve cannot hold setpoint. You will see flow drop at high demand. Raise the regulator pressure or choose an MFC with a different valve orifice.
Do I need metal seals for all CVD gases? Not for nitrogen, argon, or oxygen. Use metal seals for silane, dichlorosilane, and other toxic or pyrophoric gases. PTFE seats are fine for inert service.
How fast can Silver Instruments quote a replacement? Usually within one working day if you send the gas, flow range, pressure, fitting, and signal. Contact by Tel, Whatsapp, or WeChat.