Description
JRM Sling Psychrometer Whirling Hygrometer Thermometer, Dry Bulb Range -10°C to 50°C & Wet Bulb Range -10°C to 50°C, Mercury-Based for Accurate Humidity Measurement
Precision Sling Psychrometer for Accurate Humidity and Ambient Temperature Measurement
The JRM Sling Psychrometer Whirling Hygrometer Thermometer is a precision-engineered meteorological instrument designed for accurate measurement of relative humidity (RH) and ambient air temperature. Equipped with Dry Bulb and Wet Bulb Mercury Thermometers, each having a measuring range of -10°C to +50°C, this instrument provides reliable humidity calculations using the psychrometric principle.
Widely used in meteorological stations, laboratories, pharmaceutical industries, HVAC systems, agriculture, educational institutions, environmental monitoring, textile industries, research centers, warehouses, and industrial quality control, the JRM Sling Psychrometer offers dependable performance without requiring electricity or batteries.
Manufactured with precision glass thermometers and a durable whirling frame, the instrument allows quick air circulation around the thermometers, ensuring highly accurate wet bulb and dry bulb temperature readings for precise humidity determination.
The JRM Sling Psychrometer remains one of the most trusted instruments for field humidity measurements due to its simplicity, portability, accuracy, and long operational life.
Accurate Measurement of Relative Humidity
Humidity is an important environmental parameter that affects manufacturing processes, storage conditions, product quality, human comfort, and scientific research.
The JRM Sling Psychrometer measures humidity by comparing the temperatures recorded by two precision thermometers:
- Dry Bulb Thermometer
- Wet Bulb Thermometer
The difference between these two readings is used to calculate Relative Humidity (RH) using standard psychrometric tables or charts.
This internationally accepted measuring method provides reliable humidity measurements without electronic sensors.
Wide Temperature Measuring Range
The instrument incorporates two precision mercury thermometers with identical measuring ranges.
Dry Bulb Range
- -10°C to +50°C
Wet Bulb Range
- -10°C to +50°C
This measuring range makes the instrument suitable for monitoring indoor and outdoor environmental conditions across various climatic regions.
Applications include:
- Weather observation
- Greenhouses
- Industrial plants
- Pharmaceutical storage
- Air conditioning systems
- Warehouses
- Laboratories
- Agricultural research
- Textile manufacturing
- Educational experiments
Mercury-Based Precision Thermometers
The JRM Sling Psychrometer uses high-quality mercury-filled thermometers, known for their excellent accuracy, stability, and long-term reliability.
Advantages
- High measurement accuracy
- Excellent repeatability
- Fast response
- Long calibration stability
- Reliable field performance
- No electronic drift
Mercury thermometers have traditionally been the preferred choice for laboratory-grade environmental measurements due to their precision.
Whirling Psychrometer Design
The sling psychrometer operates by manually rotating (whirling) the instrument through the air.
During rotation:
- Air flows rapidly over both thermometers.
- The wet bulb thermometer cools through evaporation.
- The dry bulb remains unaffected.
- The temperature difference is established.
- Relative humidity can then be accurately calculated.
Benefits
- Uniform airflow
- Improved measurement accuracy
- Fast stabilization
- Reliable humidity determination
- Suitable for outdoor measurements
The whirling mechanism ensures consistent airflow, which is essential for obtaining accurate psychrometric readings.
Durable and Portable Construction
The JRM Sling Psychrometer is designed for convenient field use.
Its lightweight yet rugged construction provides:
- Easy portability
- Comfortable handling
- Strong mechanical durability
- Reliable outdoor performance
- Long service life
The compact design makes it an ideal instrument for engineers, technicians, researchers, meteorologists, and field inspectors.
No Electricity Required
Unlike digital humidity meters, the JRM Sling Psychrometer requires no electrical power.
Advantages
- No batteries
- No charging
- No electronic sensors
- No electrical interference
- Reliable in remote areas
- Suitable for field applications
This makes it particularly valuable for environmental monitoring where power availability is limited.
Accurate Humidity Determination
After obtaining the wet bulb and dry bulb temperatures, humidity can be determined using:
- Psychrometric tables
- Humidity charts
- Psychrometric calculator
- Standard humidity formulas
The instrument provides dependable data for:
- Relative Humidity (RH)
- Dew Point (using charts)
- Moisture analysis
- Environmental studies
- Climate monitoring
Suitable for Multiple Industries
The JRM Sling Psychrometer is widely used in numerous industries requiring precise environmental monitoring.
1. Meteorological Departments
Measures atmospheric temperature and humidity for weather forecasting and climate studies.
2. Pharmaceutical Industry
Monitors environmental conditions in production areas, storage rooms, and laboratories.
3. HVAC Industry
Measures humidity levels during commissioning and maintenance of air-conditioning systems.
4. Textile Industry
Maintains optimum humidity levels during spinning, weaving, dyeing, and finishing operations.
5. Agriculture
Monitors environmental conditions in farms, nurseries, and greenhouses.
6. Food Industry
Ensures proper humidity during food processing and storage.
7. Educational Institutions
Used in physics laboratories, environmental science experiments, and engineering education.
8. Research Laboratories
Supports environmental research and controlled testing applications.
9. Warehouses
Monitors storage conditions for moisture-sensitive products.
10. Industrial Manufacturing
Measures workplace environmental conditions for quality assurance.
Easy to Operate
Operating the sling psychrometer is simple:
- Moisten the wet bulb wick using clean distilled water.
- Rotate the instrument using the handle for approximately 20–30 seconds.
- Record both thermometer readings.
- Refer to a psychrometric chart or humidity table.
- Determine relative humidity.
This straightforward procedure delivers accurate and repeatable results without complex calibration.
Low Maintenance Instrument
The JRM Sling Psychrometer is designed for long-term reliability with minimal maintenance.
Routine maintenance includes:
- Keeping thermometers clean
- Replacing the wet bulb wick when necessary
- Using clean distilled water
- Protecting glass thermometers during storage
- Periodic calibration verification
Its mechanical construction minimizes maintenance costs and enhances operational life.
Long Operational Life
Manufactured using precision glass thermometers and high-quality mechanical components, the JRM Sling Psychrometer delivers years of dependable performance.
The instrument offers:
- Stable calibration
- Accurate readings
- Rugged construction
- Reliable field operation
- Long service life
- Consistent measurement performance
It continues to be one of the most trusted humidity measurement instruments worldwide.
Why Choose JRM Sling Psychrometer?
The JRM Sling Psychrometer Whirling Hygrometer Thermometer combines proven psychrometric measurement principles with precision mercury thermometers to provide accurate and dependable humidity monitoring in laboratories, industries, and field applications.
Whether used in meteorological stations, pharmaceutical laboratories, HVAC systems, agricultural research, environmental monitoring, textile industries, warehouses, educational institutions, food processing plants, or industrial quality control, the JRM Sling Psychrometer Whirling Hygrometer Thermometer provides precise humidity measurement, dependable temperature monitoring, and long-lasting performance. Its rugged mechanical design, proven measuring principle, and precision mercury thermometers make it a preferred choice for professionals requiring accurate environmental monitoring.
Japsin Instrumentation – Since 1974


Meera Desai –
Great investment
Neev Choudhury –
Good Product
Saanvi Menon –
Nice Product