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Quick Answer: Alicat Scientific flow meters are often specified for ultra-low pressure drop gas flow management arrays because they combine mass flow, volumetric flow, pressure and temperature in one device. Silver Automation Instruments supplies compatible thermal mass flow meters and pressure transmitters for these arrays. Send us your pressure (bar), temperature (°C), pipe size (DN), and flow range for a quote.
In gas flow management arrays, pressure drop is a daily operating cost. A 50 mbar extra drop across a flow meter on a 12 mbar budget can stop a pilot plant. This is why engineers look for flow meters with a low internal restriction. Alicat Scientific flow meters use a laminar flow element. This design gives a linear signal and a low pressure drop. We have seen customer sites in Vietnam where the total pressure budget for an array was 15 mbar. Every mbar counted.
Here is the thing. A pressure drop number on a datasheet is only one part. The actual drop depends on gas type, flow rate, temperature and inlet pressure. Air at 20 °C and 1 bar behaves differently from methane at 40 °C and 0.8 bar. You need to state these values before you compare suppliers.
Multi-channel arrays are common in gas blending, burner control, fuel cell testing and bioreactor feeds. A typical array has 4 to 12 channels. Each channel needs a mass flow meter or controller. Alicat Scientific flow meters are often built into these arrays with RS-232, RS-485, analog 0-5 V and 4-20 mA outputs. Some versions include totalizer functions and gas select menus. These features reduce wiring and PLC analog input cards.
We do not sell Alicat devices directly. But we do supply thermal mass flow meters with similar output options. Our meters support 4-20 mA HART, RS-485 Modbus and pulse output. For arrays with DN15 or DN25 process connections, this works well. Most engineers skip the proprietary software part and ask for a standard Modbus map. That is a practical request.
When you specify a gas flow meter for a low pressure drop array, list these parameters. First, the gas type or gas mixture. Second, the minimum and maximum flow rate in kg/h or slpm. Third, the inlet pressure in bar or mbar. Fourth, the temperature in °C. Fifth, the allowed pressure drop in mbar. Sixth, the process connection size such as DN15 or DN25. Seventh, the output signal such as 4-20 mA HART or Modbus RTU. Eighth, the hazardous area rating such as ATEX Zone 1 or Zone 2.
We often see spec sheets with a missing pressure budget. Then the supplier cannot confirm the drop. A flow meter with a 5 mbar drop at 50 slpm may look good. But the pressure drop is not a single number. At 200 slpm the drop can rise to 25 mbar. This is not a linear relationship. It follows the square of the flow rate for turbulent elements. Laminar flow elements such as those in Alicat Scientific flow meters have a more linear relationship. That is why they are preferred for array service.
Install the flow meter with straight inlet and outlet runs. For thermal mass flow meters, a 10 DN straight run before the meter and 5 DN after is enough in most cases. Do not install the meter directly after a control valve or an elbow. Flow disturbances create false readings without raising the pressure drop. In multi-channel arrays, place the pressure sensor downstream of the flow meter. This gives a stable pressure drop value for each channel. Here is the thing. A small leak in the compression fitting can cause a larger reading error than the pressure drop itself. Use a leak test with soap water or a handheld sniffer before startup.
Air, nitrogen, argon, biogas and natural gas are common in low pressure drop arrays. Thermal mass flow meters are calibrated for one gas or a known mixture. If you change the gas after installation, you must change the calibration factor. Alicat Scientific flow meters include a gas select menu with many gases. Silver Instruments thermal mass flow meters can be ordered with multi-gas calibration or a fixed gas curve. For biogas with 60 percent methane and 40 percent carbon dioxide, send the exact composition. A wrong gas curve can shift the reading by more than 5 percent. This is not a small error when you batch gas into a reactor.
Silver Automation Instruments supplies process instruments to industrial users in Southeast Asia, Oceania, Latin America, Africa and the Middle East. Our range includes thermal mass flow meters, pressure transmitters, Coriolis mass flow meters, electromagnetic flow meters, vortex flow meters and oval gear flow meters. For gas flow management arrays, our thermal mass flow meter works with air, nitrogen, biogas, natural gas and light hydrocarbons. You can get a DN15 or DN25 body, PT100 temperature compensation, and a 4-20 mA HART output.
In practice, a paint manufacturer in Southeast Asia asked us last year for a 6-channel air flow array. The pressure drop limit was 8 mbar per channel. We supplied six thermal mass flow meters with a range of 0 to 80 slpm each. The customer connected all six meters to a small PLC over RS-485 Modbus. This saved them one analog input card. The array has been running for nine months without a zero drift issue.
Send us your pressure (bar), temperature (°C), pipe size (DN), and flow range. Also tell us the gas type and allowed pressure drop. So we ask you to send these values first. Our team will reply with a model, a price and a lead time. You can reach us by Tel: +86-25-68650347, WhatsApp: +86-25-52155837, or WeChat: +86 15365082610. You can also visit our website flow-meter.com.au.
Question: What is the typical pressure drop for a gas flow meter in an array?
Answer: For a laminar flow element meter, the drop is often between 1 and 10 mbar at moderate flow. The exact value depends on gas type, flow rate and inlet pressure. Always ask the supplier for a drop curve, not a single point.
Question: Can Alicat Scientific flow meters be replaced with Silver Instruments thermal mass flow meters?
Answer: In many low pressure drop gas arrays, yes. You need to compare the pressure drop curve, output signal, accuracy class and hazardous area certificates. Send us the Alicat model number and your gas conditions. We will propose a compatible Silver Instruments meter.
Question: What output signals do you support for multi-channel arrays?
Answer: We support 4-20 mA, 4-20 mA HART, RS-485 Modbus RTU and pulse output. For arrays with many channels, Modbus often saves wiring and PLC input cards.
Question: Do you supply flow meters for biogas or natural gas?
Answer: Yes. Our thermal mass flow meters handle biogas, natural gas, air, nitrogen and light hydrocarbons. Specify the gas composition if it is a mixture. This affects the accuracy and the pressure drop calculation.
Question: How fast can Silver Instruments deliver after an order?
Answer: Standard thermal mass flow meters usually ship in 10 to 15 working days. Custom ranges or ATEX Zone 1 certificates may add 7 to 10 days. WhatsApp us at +86-25-52155837 for current lead times.
