NKFD-L Digital Mass Flow Meter / Controller (Low Flow Range)

Thermal Mass Flow Measurement and Control for Low-Flow Gas Applications

Product Name: Digital Mass Flow Meter/Controller
Series: NKFD-L
Product Types: NKFD-LM Mass Flow Meter / NKFD-LC Mass Flow Controller

Direct Answer

The NKFD Digital Mass Flow Meter/Controller is designed for low-flow gas mass flow measurement and control. Based on the thermal measurement principle, the instrument detects gas mass flow and converts the measurement into electrical signals for display, monitoring, communication, or control.

The NKFD-L series includes two configurations: NKFD-LM Mass Flow Meter, primarily for gas mass flow measurement, and NKFD-LC Mass Flow Controller, which combines flow measurement with closed-loop flow control.

According to the supplied product specifications, the available flow ranges cover 15 SCCM to 30 SLM, with analog signal, RS232/RS485 communication, and MODBUS protocol options.

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Key Takeaways

• Uses a thermal measurement principle for low-flow gas mass flow measurement.
• Flow ranges cover 15 SCCM to 30 SLM, with specific ranges selected according to the model code.
• NKFD-LM is designed for mass flow measurement.
• NKFD-LC combines mass flow measurement with automatic flow control.
• The controller provides a valve control range of up to 50:1, while the mass flow meter provides a range ratio of 100:1.
• Supports 0–5 VDC, 1–5 VDC, and 4–20 mA signal options.
• Supports RS232/RS485 communication and MODBUS protocol.

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What Is the NKFD Digital Mass Flow Meter / Controller?

The NKFD Digital Mass Flow Meter/Controller is a digital instrument designed for measuring and controlling the mass flow of gases at relatively low flow rates.

The series is based on a thermal mass flow measurement principle. According to the supplied product information, the sensor uses the change in heat transfer associated with flowing gas to obtain a flow-related measurement signal.

The NKFD-L series is available in two main configurations:

NKFD-LM — Digital Mass Flow Meter

The NKFD-LM is primarily used for gas mass flow measurement. It can provide local digital display and electrical output signals according to the selected configuration.

NKFD-LC — Digital Mass Flow Controller

The NKFD-LC combines mass flow measurement and flow control. The measured flow signal is compared with the preset flow value, and the controller drives the control valve according to the deviation to regulate the gas flow.

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How Does the NKFD Mass Flow Meter Work?

The NKFD uses a thermal flow measurement principle.

As gas flows through the sensing section, heat transfer characteristics change with the flow condition. The sensor detects the corresponding thermal change and generates a flow-related electrical signal.

For the NKFD-LC Mass Flow Controller, the measured flow signal is amplified and compared with the preset control signal. The controller then adjusts the control valve according to the difference between the measured value and the setpoint.

This creates a closed-loop flow control process, allowing the actual flow rate to be regulated toward the specified setpoint.

The basic functional difference is:

NKFD-LM:
Gas Flow → Thermal Sensor → Flow Measurement → Signal Output

NKFD-LC:
Gas Flow → Thermal Sensor → Flow Measurement → Setpoint Comparison → Valve Control → Flow Regulation

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NKFD-L Series Key Technical Parameters

The following specifications are organized from the supplied product information. The actual configuration should be confirmed according to the selected model and technical requirements.

Note: Some pressure, power supply, sealing, fitting, and signal parameters vary according to the selected configuration. Please confirm the final specification with NOIKE-AH before ordering.

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Available Flow Ranges

The NKFD-L series provides multiple low-flow measurement ranges.

SCCM Ranges

• 15 SCCM
• 200 SCCM
• 300 SCCM
• 500 SCCM

SLM Ranges

• 1 SLM
• 2 SLM
• 3 SLM
• 5 SLM
• 10 SLM
• 20 SLM
• 30 SLM
• 55 SLM

Important: The general technical specification provided for the product indicates a flow range of 15 SCCM–30 SLM, while the selection table also lists a 55 SLM option. Therefore, the applicable flow range should be confirmed against the specific model code and final technical configuration.

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NKFD-L Product Selection

The NKFD-L series uses a model coding system to define the product configuration.

The main selection parameters include:

1. Product Type

• C — Mass Flow Controller
• M — Mass Flow Meter

2. Pressure Rating

• M — 3 MPa
• Z — 10 MPa, for mass flow meter only

3. Local Display

• N — Without LCD display
• X — With LCD display

4. Flow Range

Available selections include:

• 15 SCCM
• 200 SCCM
• 300 SCCM
• 500 SCCM
• 1 SLM
• 2 SLM
• 3 SLM
• 5 SLM
• 10 SLM
• 20 SLM
• 30 SLM
• 55 SLM

5. Flow Input Signal

• 0–5 VDC
• 4–20 mA
• 1–5 VDC

6. Output Signal

• 0–5 VDC
• 4–20 mA
• 1–5 VDC

7. Power Supply

• ±15 VDC
• 24 VDC

8. Communication Interface

• RS485
• RS232

9. Seal Material

• Fluororubber
• PTFE
• Chloroprene rubber
• Other options

10. Process Connection

• φ3
• φ6
• 1/8″
• 1/4″
• Other connections available upon consultation

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How to Select the NKFD Mass Flow Meter or Controller?

Correct selection should be based on the actual gas and operating conditions of the application.

1. Determine the Required Flow Range

First determine the minimum, normal, and maximum gas flow rates.

Then select an appropriate NKFD flow range based on the actual operating conditions.

For very low-flow applications, SCCM ranges may be applicable. Higher flow requirements can be matched with the corresponding SLM range.

2. Select the Product Type

For applications requiring flow measurement only:

NKFD-LM Digital Mass Flow Meter

For applications requiring automatic flow regulation according to a setpoint:

NKFD-LC Digital Mass Flow Controller

3. Confirm the Operating Pressure

The operating pressure and differential pressure should be confirmed before selecting the model.

The maximum pressure rating should not be treated as the normal operating pressure. The actual operating pressure, differential pressure, and pressure resistance requirements should all be considered during selection.

4. Select the Signal Interface

The signal interface should match the PLC, data acquisition system, control system, or other connected equipment.

Available options include:

• 0–5 VDC
• 1–5 VDC
• 4–20 mA
• RS232
• RS485 / MODBUS

5. Confirm the Process Connection

Select the appropriate connection according to the gas piping and equipment interface:

φ3, φ6, 1/8″, or 1/4″.

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NKFD Mass Flow Meter / Controller Applications

According to the supplied product information, NKFD can be used in a variety of applications involving low-flow gas measurement and control, including:

• Vacuum systems
• Coating and thin-film processes
• Solar energy equipment
• Semiconductor applications
• Petrochemical processes
• Coal and metallurgy
• Gas generation and gas distribution
• Environmental protection equipment
• Instrument analysis

The NKFD series is particularly suitable for systems requiring low-flow gas measurement, monitoring, signal transmission, or closed-loop flow control.

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NKFD-LM vs. NKFD-LC

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Frequently Asked Questions

1. Is the NKFD designed for liquid or gas measurement?

The supplied product information describes the NKFD as a thermal mass flow instrument for gas mass flow measurement and control. The applicable gas and calibration conditions should be confirmed according to the specific model and application.

2. What is the difference between NKFD-LM and NKFD-LC?

The NKFD-LM is a mass flow meter designed primarily for flow measurement.

The NKFD-LC is a mass flow controller that combines flow measurement with automatic flow regulation through a control valve.

3. What is the flow range of the NKFD?

The general product specification indicates a range of 15 SCCM to 30 SLM. The selection table provides several specific flow ranges, and the final range should be confirmed according to the selected model.

4. Does the NKFD support 4–20 mA output?

Yes. The selection table provides 4–20 mA signal options, as well as 0–5 VDC and 1–5 VDC options.

5. Does the NKFD support digital communication?

Yes. The supplied specifications include RS232, RS485, and MODBUS protocol options.

6. What power supplies are available?

The selection table provides ±15 VDC and 24 VDC power supply options. The applicable power supply should be confirmed according to the selected configuration.

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Conclusion

The NKFD Digital Mass Flow Meter/Controller is designed for low-flow gas mass flow measurement and control using a thermal measurement principle.

The series includes the NKFD-LM Mass Flow Meter and NKFD-LC Mass Flow Controller, with multiple SCCM and SLM flow ranges. Depending on the configuration, the instrument supports 0–5 VDC, 1–5 VDC, 4–20 mA, RS232, RS485, and MODBUS interfaces.

For applications such as vacuum systems, coating, solar energy, semiconductor equipment, petrochemical processes, gas distribution, environmental equipment, and instrument analysis, selection should be based on the gas medium, required flow range, operating pressure, differential pressure, signal type, power supply, communication interface, and process connection.

For detailed specifications and model selection, please contact NOIKE-AH staff for consultation.