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HFRR (High Frequency Reciprocating Rig)
/ Accessories
HFRR/HFR2 Humidity Controlled Cabinet (Part code: HFRHCAB)
On this page: Overview | Humidity and temperature control | Humidity and temperature measurement | Dimensions
Overview
The HFRR Humidity Controlled Cabinet (HFRHCAB) is designed as an accessory for the HFRR High Frequency Reciprocating Rig to allow tests to be carried out at constant temperature and relative humidity.
The cabinet, which is supplied with a stainless steel stand for the HFR test head and a coated desiccant tray, is easy to use and virtually maintenance free. Preliminary tests using the humidity controlled cabinet show increased repeatability and reduced scatter.
Items supplied:
- Humidity cabinet including cables
- Temperature and humidity sensor
- HFRR stand and tray
Items not supplied and are required to control the humidity:
- Salt (chosen from the table below)
- De-ionised water
Humidity and temperature control
The cabinet temperature can be controlled electronically from the prevailing ambient temperature up to 50°C with stability of ±1°C. The relative humidity within the cabinet is controlled using appropriate salt solutions. Particular combinations of temperature and salt solution are available which will give an internal absolute vapour pressure of 1.4kPa. This is the "standard" AVP as defined in CEC-F-06-A-96.
The choice of salt depends on the ambient temperature range in the laboratory where the cabinet it located. A saturated solution is made up from one of the following chemicals below in de-ionised water. This is then filled into the desiccant tray where both the temperature and humidity can then stabilise.
*Please note that salts below are not supplied with the humidity cabinet and need to be purchased either independently, from your distributor or PCS Instruments.
Ambient Temperature
Less than 20°C
Less than 25°C
Less than 30°C
Less than 30°C
Recommended Salt
Sodium Bromide(NaBr)
Potassium Carbonate (K2CO3)
Sodium Iodide (Nal)
Magnesium Chloride (MgCl2)
Cabinet Temperature (°C)
20
25
28
30
Rapid air circulation over the desiccant tray and support platform combined with a large heat dissipating back plate promotes quick and even heat distribution within the unit. The plate glass door features a spring-loaded mechanism which maintains an air-tight seal, ensuring that the internal atmosphere remains constant.
Creating the saturated solution
When making a saturated solution from the chosen chemical in de-ionised water take care to observe all precautions appropriate to the particular chemical.
To make-up the saturated solution you will need 500ml of de-ionised water and at least 750ml of chosen salt from the table shown above. Start by filling a beaker with the 500ml of de-ionised water and gradually add 500ml of the salt while mixing. When the salt is mixed with the de-ionised water the beaker will get slightly warm so caution must be taken while handing the beaker. Once saturation is complete then pour the solution into the tray inside the humidity cabinet.
Applying the saturated solution to the desiccant tray
Add 250ml more of the chosen salt to the tray and mix until there is undissolved solid in the bottom of the tray as shown below. In order for the humidity control to work properly there must always be a mixture of free liquid and undissolved solid in the tray.
Undissolved solution in the desiccant tray
Slide the tray beneath the support platform so that the back edge of the tray is level with the front edge of the flat ledge on the back plate.
Humidity and temperature measurement
The humidity and temperature is recorded either using a manual recording humidity/temperature measuring instrument (HFR2) or an automatic recording humidity/temperature probe (HFRR) that can be integrated with the latest HFRR, allowing measurement of 5 to 95% RH within a 0 to 50°C range.
HFRR integrated humidity probe
Dimensions
External (overall)
Internal
Width
640mm
530mm
Depth
390mm
350mm
Height
630mm
500mm
Construction
Cabinet - Stainless steel
Fittings - Plated/Painted steel
Door - Plate glass
Interior - Stainless steel
Exterior - Powder coated
Power Supply
Proven by a third party test house to meet the requirements of the European EMC Directive, the unit also complies with the safety requirements of the Machinery and Low Voltage Directives.
Voltage - 220/240volts 50Hz (100/110V 60Hz also available)
Power- 200 Watts
Weight
Net - 17 kg
*This cabinet as supplied is NOT SUITABLE for gasoline testing. Please consult PCS for further information concerning gasoline tests.
