HNB Portable Wet Bulb Hygrometer – Complete Data Sheet
📦 Product information
Item code: HNB
Italian name: Portable wet bulb hygrometer
English name: Incubation Hygrometer
Type: Analog humidity control instrument
Compatibility: Universal - all incubators
💡 ESSENTIAL TOOL: The wet bulb hygrometer is the gold standard for checking the accuracy of digital sensors. Even the best monitors can fail over time. Having independent monitoring means protecting every incubation cycle.
🔍 What is a wet bulb hygrometer?
The wet-bulb hygrometer (or psychrometer ) is an instrument that measures the relative humidity of the air using the principle of water evaporation. This method, developed in the 19th century, is still considered one of the most accurate and reliable for measuring humidity.
A quail farmer from Treviso wrote to me: "The control unit showed 55%, but the eggs were too dry, resulting in poor hatchability. I bought a wet-bulb hygrometer as a check and discovered that the actual humidity was only 42%. The control unit's sensor was faulty. Using the analog hygrometer as a reference, I corrected the parameters, and the subsequent hatchability was 82%.
Operating principle:
- A glass bulb contains thermometric alcohol
- The bulb is wrapped in a muslin stocking (moistening cloth) commonly known as a wick.
- The sock is soaked in a water tank and always stays moist.
- Evaporation of water from the sock lowers the temperature of the bulb
- The temperature difference indicates the relative humidity
- The lower the humidity in the air → greater evaporation → lower temperature
Unique advantage of this model: It is factory calibrated to operate at 37.8°C (100°F) , the optimum incubation temperature. The graduated scale directly indicates the percentage of relative humidity (%RH) without the need for conversion tables .
⚙ Technical features
| Characteristic | Value |
|---|
| Measurement type | Psychrometric (wet bulb) |
| Precision | ±3% RH |
| Temperature calibration | 37.8°C / 100°F |
| Humidity range | 40% - 100% RH |
| Graduated scale | Aluminum with direct %RH indication |
| Diet | None (analog) |
| Dimensions | 20 × 5 × 5 cm |
| Weight | 0.3 kg |
| Include | Moisturizing cloth (muslin stocking) |
📊 Comparison: Wet Bulb vs. Hair Hygrometer
Many breeders wonder which system is best for incubation. Here's a detailed comparison:
| Characteristic | Wet Bulb | Hair |
|---|
| Precision | ±3% RH | ±5-10% RH |
| Speed of response | Medium-high (minutes) | Slow (hours) |
| Calibration | Factory, stable | Frequent, unstable |
| Maintenance | Periodic sock change | Hair regeneration |
| Wear sensitivity | Low | High (hair degrades) |
| Temperature influence | Calibrated for 37.8°C | Errors below -30°C |
| Diet | None | None |
| Ideal for incubation | YES | Partially |
✅ Advantages of a hair hygrometer
- It works without electronics, without power supply or batteries
- Well-made models claim accuracies of approximately ±3% RH
- It can be robust, suitable for less than perfect conditions
- For general use or complementary control it may be fine
❌ Disadvantages of hair hygrometer for incubation
- Slower reaction speed: It may take hours for the hair to stabilize
- Extremely sensitive to calibration and maintenance: If the hair is worn, dirty or not regenerated, the readings become inaccurate
- Accuracy ±5-10%: For professional incubation ±1-3% is required
- Not incubation specific: Many models are made for general environments (homes, archives)
- Nonlinearity of response: Temperature and operating range influence accuracy
- Calibration difficulty: In professional systems, an easily calibratable sensor is needed
🏆 Comparison conclusion
For professional incubation, the wet bulb hygrometer is the best choice thanks to: specific calibration for 37.8°C, faster response, superior accuracy, and direct reading in %RH without tables.
🔧 Instructions for use
Preparation
- Fill the glass tube completely with water (preferably demineralized)
- Make sure the cotton sock is attached correctly
- Make sure the sock is clean and wet
- Use distilled or demineralized water
Measurement
- Place the hygrometer in the incubator
- Wait at least 1 hour for stabilization
- Read the humidity value on the graduated scale
Corrections for incubator type
FORCED VENTILATION INCUBATORS:
- When the temperature reaches 37.8°C or 100°F, read the humidity level directly
- This is the correct relative humidity value
⚠️ Important warnings
FOR CORRECT OPERATION:
- If it reads 100%: Check that the sock is outside the tube and is wet. If necessary, moisten manually.
- Changing the sock: Replace the moistening cloth if it is dirty or hardened by limescale.
- Demineralized water: Prolongs the life of the sock (avoids limescale deposits)
- Sock position: It must completely fill the thermometer bulb, tighten well
- Water level: Keep the glass tube at least 1/3 full at all times
💡 Applications
- Digital sensor check: Accuracy check of EVO PLUS, MiniLED Advanced control units, etc.
- Reference instrument: To calibrate other hygrometers
- Diagnosing Problems: When Hatching Goes Wrong
- Incubators without hygrometers: As the primary tool for humidity control
- Hatching: Check high humidity in the last few days
- Backup: Standalone instrument without batteries
🔧 Maintenance
- Sock change: Replace with each new incubation cycle or when it shows signs of wear/dirt
- Pipe cleaning: If limescale deposits form, clean with diluted vinegar
- Fresh Water: Change water regularly to avoid algae/bacteria
- Storage: When not in use, empty the tube and store dry.
Replacement socks: Available with item code 28
🛒 Commercial information
Price: €24.50 (VAT excluded, shipping excluded)
Includes: Complete hygrometer + moistening cloth (muslin sock) - ready to use
FIEM COMO WAREHOUSE – Padovan Poultry Farming: professional tools for incubation.
💡 Related products
- Spare socks code 28 – Spare moistening cloth
- Analog Thermometer °F (0.5/A) – Temperature Control
- T/H Probe for EVO PLUS/MiniLED Advanced – Digital Sensor
📦 Logistics and times
- Shipping: 1 business day
- Delivery: 2-4 working days
- Departure: FIEM Como Warehouse
- Packaging: Protected for precision instruments
✅ Guarantee
❓ Frequently Asked Questions (FAQ)
Q: Do I need to use tables to convert the reading to %RH?
A: No! This hygrometer is calibrated to 37.8°C and displays the relative humidity percentage directly on the graduated scale. No calculations required.
Q: How often should I change my socks?
A: We recommend replacing it when it becomes dirty, damaged, or starts to become stiff due to limescale. Using demineralized water extends its life.
Q: Is this more accurate than my ECU sensor?
A: The wet bulb hygrometer has an accuracy of ±3% RH, similar to the best digital sensors. The advantage is that it doesn't "fail" over time and serves as an independent reference.
Q: How long does it take to read?
A: Wait at least 1 hour after placement for a stable and accurate reading.
Q: Why is it better than the hair hygrometer?
A: Faster response, superior accuracy, specific calibration for incubation at 37.8°C, and does not degrade with wear like hair.
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📋 Legal Notice and Rights
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PLAGIARISM PROHIBITED: Total or partial reproduction of this text/data on other websites is monitored and will be legally prosecuted (DMCA and Law 633/41) without notice.
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