Product Introduction

The NHJ-400NM Helium Mass Spectrometer Leak Detector is a high-sensitivity instrument designed to detect and locate leaks in vacuum systems, sealed components, and industrial products. Based on helium mass spectrometry and reverse-diffusion technology, it combines an imported molecular pump, a 180° non-uniform magnetic field, and automatic control functions for efficient leak detection.

The NHJ-400NM supports automatic peak scanning, zero adjustment, calibration, and range switching, reducing the need for repeated manual adjustments. With a minimum detectable leak rate of 5 × 10⁻¹³ Pa·m³/s, a response time of no more than 1 second, and a startup time of no more than 2 minutes, it is designed for applications requiring sensitive and rapid leak testing.

Its vacuum and sniffer detection capabilities, multiple signal interfaces, and contamination-resistant gas-path design make it suitable for industrial manufacturing, vacuum equipment inspection, sealed-component testing, and quality control.

Performance Features

1. High-Sensitivity Helium Leak Detection: Provides a minimum detectable leak rate of 5 × 10⁻¹³ Pa·m³/s for sensitive leak testing.

2. Wide Measurement Range: The specified leak-rate display range extends from 1 × 10⁻³ to 1 × 10⁻¹³ Pa·m³/s.

3. Automatic Operation: Supports automatic peak scanning, zero adjustment, calibration, and measurement range switching.

4. Fast Startup and Response: Startup time is ≤2 minutes, with a specified response time of ≤1 second.

5. Advanced Vacuum Technology: Uses an imported molecular pump and reverse-diffusion technology to support vacuum leak detection.

6. Contamination-Resistant Gas Path: The gas-path design is intended to improve pumping performance, shorten background recovery time, and reduce internal contamination.

7.  Precision Leak Detection Port: A customized filter helps prevent debris and copper particles from entering the instrument.

8.  Vacuum and Sniffer Modes: Supports vacuum leak testing and sniffer-based leak localization, with separate specified detection ranges.

9. Electromagnetic and Thermal Isolation: Separation of the machine structure and circuitry is designed to reduce temperature-related and electromagnetic interference.

10. Multiple Integration Interfaces: Multi-mode inputs and outputs facilitate connection to compatible automation and control systems.

12. Multiple Display Units: Displays leak rates in Pa·m³/s, mbar·L/s, atm·cc/s, or ppm, depending on the selected mode and configuration.

Working Principle

The NHJ-400NM uses helium mass spectrometry to identify helium entering a test system through leaks.

1. Evacuation and Gas Sampling

In vacuum testing, the connected test component is evacuated using the leak detector's pumping system. Helium is introduced around potential leak locations or into the test environment, depending on the selected procedure.

2. Helium Detection

Helium entering the instrument is analyzed using the mass spectrometer. The magnetic field separates ions according to their mass-to-charge ratio, enabling the instrument to identify the helium signal against the background.

3. Signal Processing and Leak-Rate Calculation

The instrument processes the detected helium signal and converts it into a leak-rate reading. Automatic zero adjustment, peak scanning, calibration, and range switching help maintain convenient operation over a wide measurement range.

4. Sniffer Leak Localization

In sniffer mode, a probe samples gas near the suspected leak location. The instrument detects helium above the background level, helping the operator identify the location of a leak.

Actual detection sensitivity depends on the test setup, background helium concentration, system cleanliness, calibration, and the selected detection method.

Technical Parameters

Note: Confirm the precise definition and operating conditions of the specified 1,500 Pa leak-detection pressure with the manufacturer. Detection performance may vary with the test configuration and method.

Application Scenarios

The NHJ-400NM helium mass spectrometer leak detector is suitable for applications where reliable detection of small leaks is important.

• Vacuum Equipment Manufacturing: Testing vacuum chambers, vacuum pipelines, valves, and vacuum assemblies.

• Sealed Components: Detecting leaks in sealed housings, enclosures, and components designed to maintain gas tightness.

• Automotive and Industrial Components: Supporting leak testing of compatible components and assemblies during manufacturing and quality inspection.

• Refrigeration and Heat-Transfer Equipment: Testing suitable sealed components, joints, and assemblies using an appropriate helium test procedure.

• Electronics Manufacturing: Inspecting compatible sealed electronic components and vacuum-related assemblies.

•  Industrial Automation: Integrating leak detection into production lines and automated inspection systems through compatible input/output interfaces.

•   Quality Control Laboratories: Performing sensitive leak tests during product development, incoming inspection, and production verification.

•   Maintenance and Troubleshooting: Using sniffer mode to help locate helium leaks in accessible test systems.

NHJ-400NM vs. Conventional Leak Detection Methods

The methods serve different purposes. The most suitable approach depends on the required leak-rate sensitivity, test object, production process, and applicable acceptance criteria.

Frequently Asked Questions (FAQ)

1. What is the NHJ-400NM helium mass spectrometer leak detector used for?

It detects and helps locate leaks in vacuum systems, sealed components, and industrial assemblies using helium as a tracer gas.

2. What is the minimum detectable leak rate?

The specified minimum detectable leak rate is 5 × 10⁻¹³ Pa·m³/s. The minimum detectable leak rate in sniffer mode is 1 × 10⁻⁸ Pa·m³/s.

3. What is the difference between vacuum mode and sniffer mode?

Vacuum testing detects helium entering an evacuated test system. Sniffer testing samples gas near a suspected leak to help locate the leak. The appropriate mode depends on the test object's design and accessibility.

4. How quickly can the NHJ-400NM start and respond?

The specified startup time is no more than 2 minutes, and the response time is no more than 1 second. Actual test-cycle time depends on the system volume, background level, and test procedure.

5. Does the instrument support automatic calibration?

Yes. It supports automatic calibration, peak scanning, zero adjustment, and measurement range switching.

6. Which units can be used to display leak rates?

Available display units include Pa·m³/s, mbar·L/s, atm·cc/s, and ppm. The suitability of each unit depends on the selected measurement mode and configuration.

7. Can the NHJ-400NM be integrated into an automated production line?

Yes. Its multiple input and output modes are designed to support integration with compatible automation equipment. Confirm the exact signal types and communication requirements before installation.

8. What environmental conditions are required?

The specified operating temperature is 5–40°C, with relative humidity no greater than 80%. The instrument requires a 220 V ±10%, 50 Hz power supply.

9. What factors affect helium leak detection accuracy?

Performance can be affected by background helium, contamination, calibration, pumping conditions, test fixture design, and the selected test procedure. Proper setup and calibration are important for reliable results.