USER'S GUIDE Vaisala Humidity Calibrator HMK15 M210185EN-C
PUBLISHED BY Vaisala Oyj P.O. Box 26 FIN-00421 Helsinki Finland Phone (int.): +358 9 8949 1 Fax: +358 9 8949 2227 Visit our Internet pages at http://www.vaisala.com/ © Vaisala 2006 No part of this manual may be reproduced in any form or by any means, electronic or mechanical (including photocopying), nor may its contents be communicated to a third party without prior written permission of the copyright holder. The contents are subject to change without prior notice.
___________________________________________________________________ Table of Contents CHAPTER 1 GENERAL INFORMATION....................................................... 3 About This Manual.................................................. 3 General Safety Considerations............................. 3 Feedback.............................................................. 4 Product Related Safety Precautions ..................... 4 Recycling.................................................................
User's Guide ________________________________________________________ CHAPTER 5 MAINTENANCE ..................................................................... 31 CHAPTER 6 SPARE PARTS AND ACCESSORIES................................... 33 CHAPTER 7 TECHNICAL DATA ................................................................
Chapter 1 ___________________________________________ General Information CHAPTER 1 GENERAL INFORMATION This chapter provides general notes for the manual and the product. About This Manual This manual provides information for operating, and maintaining Vaisala Humidity Calibrator HMK15. General Safety Considerations Throughout the manual, important safety considerations are highlighted as follows: WARNING Warning alerts you to a serious hazard.
User's Guide ________________________________________________________ Feedback Vaisala Customer Documentation Team welcomes your comments and suggestions on the quality and usefulness of this publication. If you find errors or have other suggestions for improvement, please indicate the chapter, section, and page number. You can send comments to us by e-mail: manuals@vaisala.com Product Related Safety Precautions Note the following precautions: CAUTION Do not modify the unit.
Chapter 1 ___________________________________________ General Information Recycling Recycle all applicable material. Dispose of batteries and the unit according to statutory regulations. Do not dispose of with regular household refuse.
User's Guide ________________________________________________________ Warranty Vaisala hereby represents and warrants all Products manufactured by Vaisala and sold hereunder to be free from defects in workmanship or material during a period of twelve (12) months from the date of delivery save for products for which a special warranty is given.
Chapter 2 _____________________________________________Product Overview CHAPTER 2 PRODUCT OVERVIEW Introduction to Vaisala Humidity Calibrator HMK15 General The HMK15 humidity calibrator has been developed for calibration and checking of humidity probes and transmitters. The functioning of the calibrator is based on the fact that certain salt solutions generate a certain relative humidity in the air above them.
User's Guide ________________________________________________________ Calibration is usually performed at least at two different humidities to ensure the sensor accuracy over the entire humidity range (0 … 100 %RH). The HMK15 calibrator is suitable for both laboratory and field usage. During transportation, the chambers can be tightly closed with specially designed transit covers. The optional transit bag (order code HM27032) helps to transport the calibrator in the vertical position.
Chapter 2 _____________________________________________Product Overview 6 = * Ready-dosed salt package with calibration certificate 7 = Calibration certificate for thermometer 8 = * Ion-exchanged water 9 = Measurement cup 10 = Measurement spoon Accessories include additional salt chambers, ion exchanged water, transit bag and ready-dosed salt packages (LiCl 11 %RH, MgCl2 33 %RH, NaCl 75 %RH, K2SO4 97 %RH).
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Chapter 3 _____________________________________Preparing the Salt Solutions CHAPTER 3 PREPARING THE SALT SOLUTIONS General Instructions - Prepare the salts using the equipment provided with the calibrator or make sure that all accessories used are suitable for preparing salt solutions and are absolutely clean. If necessary, wash them carefully and rinse several times before preparing the salt solutions. The last rinse must be made with distilled or ion exchanged water.
User's Guide ________________________________________________________ - At the bottom of the salt chamber there must not be more than 1 cm of undissolved salt and liquid. Otherwise, the sensor to be calibrated can be immersed into the solution. If necessary, verify the amount for example with the measurement spoon. - Various standards (ASTM E104-85, DIN 50008, JIS Z8806) include recommendations and instructions on how to prepare and store salt solutions.
Chapter 3 _____________________________________Preparing the Salt Solutions Potassium sulphate generates a reference humidity of approximately 97 %RH. Potassium sulphate is used as the wet end reference (gain) for probes measuring in applications with very high humidities (90 … 100 %RH, for example outdoor and concrete measurements). Prepare the salt solutions according to the following instructions. Measure the salts carefully if you do not use the ready-dosed packages. 1.
User's Guide ________________________________________________________ 0606-166 Figure 3 3. Pour a correct dose of ion exchanged water into the chamber; dry the measurement cup Sprinkle the contents of a salt package (or measure the salt according to the table) in small quantities into the chamber, stirring constantly. When measuring with the measurement cup, make sure that the cup is clean and dry. Rinse and dry the cup after every use.
Chapter 3 _____________________________________Preparing the Salt Solutions 0606-167 Figure 4 Sprinkle a correct dose of salt into the chamber stirring constantly 4. When all salt has been sprinkled into the chamber, the saturated salt solution should have the ratio of 60 … 90 % undissolved salt to 10 … 40 % liquid. 5. Close the chamber with the chamber cover (Figure 5).
User's Guide ________________________________________________________ 0606-168 Figure 5 6. NOTE Close the chamber with the chamber cover Fasten the salt chamber on the holder in the base plate and close the measurement holes with rubber plugs. The chambers can also be used as individual checkers without the base plate. The plugs have three steps, each of which is suitable for a certain hole diameter: the first step for the 12 mm, the second step for the 13.5 mm and the third step for the 18.5 mm hole.
Chapter 3 _____________________________________Preparing the Salt Solutions 0606-169 Figure 6 NOTE Mark the chamber and covers with stickers 8. Allow approximately 24 hours for stabilization before use so that the salt solution reaches the equilibrium humidity. 9. See Chapter 5 Maintenance on page 31 on how to maintain the salt solutions. If you do not use the instrument for a longer period of time, close the chambers with transit covers.
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Chapter 4 ________________Instructions for the Calibration of Humidity Instruments CHAPTER 4 INSTRUCTIONS FOR THE CALIBRATION OF HUMIDITY INSTRUMENTS General Instructions Usually, the errors during humidity calibration are due to temperature differences. A temperature difference of ±1 °C at +20 °C between the air in the chamber and the sensor causes an error of ±3 %RH at 50 %RH and an error of ±6 %RH at 97 %RH.
User's Guide ________________________________________________________ NOTE Even the smallest water drop on the probe near the sensors distorts the readings. Make sure that chamber covers and plugs are carefully closed. 0606-170 Figure 7 Salt chamber The following numbers refer to Figure 7 above 1 2 3 4 5 6 7 = = = = = = = HMP233 probe O-rings Sensors Max.
Chapter 4 ________________Instructions for the Calibration of Humidity Instruments Thermometer The calibrator includes a thermometer which can contain either mercury or red capillary liquid. If the thermometer contains mercury, it is delivered with a calibration certificate. The accuracy of the mercury thermometer is sufficient for checking the transmitter's temperature channel if desired.
User's Guide ________________________________________________________ During calibration, the thermometer is inserted into the 13.5 mm hole of a salt chamber. Press it downwards until it passes the O-rings. The thermometer is correctly in place when you can feel a resistance while pressing it downwards. 0606-172 Figure 9 During calibration, the thermometer is inserted into the 13.
Chapter 4 ________________Instructions for the Calibration of Humidity Instruments 0606-173 Figure 10 Place the thermometer in holders when not in use Calibration Perform the calibration according to the following instructions: - Leave the HMK15 calibrator and the probe at the calibration site for at least 30 minutes before starting the calibration in order to let the probe temperature stabilize to the room temperature.
User's Guide ________________________________________________________ - Take off the grid or filter protecting the sensor. Take care not to damage the sensor. - Some 12 mm probes need a adapter fitting to fit into the 13.5 mm hole. Adapter fitting prevents sensor from soaking in the salt liquid. In case you need an adapter fitting, take off the grid or filter and replace it with the adapter fitting. Two adapter fittings are attached on the base plate of the HMK15, see Figure 1 on page 8.
Chapter 4 ________________Instructions for the Calibration of Humidity Instruments - Insert the probe into a suitable hole of the NaCl (or K2SO4) salt chamber. The shorter the time the hole stays open before inserting the probe, the shorter the stabilization time required. - Wait until the humidity reading stabilizes; this takes about 10 … 30 minutes. Note that in high humidities the risk for errors increases. Therefore, the stabilization time should be longer (approximately 20 … 40 minutes).
User's Guide ________________________________________________________ On-Site Calibrations and Transportation The HMK15 calibrator is easily trasferred from one place to another. Two O-rings seal the transit cover on the chamber. The optional transit bag helps to transport the calibrator so that chambers stay in the vertical position. Furthermore, the bag can be used for housing the calibrator during calibration.
Chapter 4 ________________Instructions for the Calibration of Humidity Instruments transportation temperature is below +18 °C, the LiCl salt chamber should be transported separately to keep the solution warm. - When the calibrator is at the calibration site, remove transit covers and fasten chamber covers on salt chambers. Close the holes with plugs. NOTE The plugs have three steps each of which is suitable for a certain hole diameter: the first step for the 12 mm, the second step for the 13.
User's Guide ________________________________________________________ The following figure illustrates an example of temperature and humidity stabilization. In this example, an HMP233 probe has been transferred from a temperature of 75 °C (oven) to a suitable hole of the NaCl salt chamber; the calibrator is at room temperature. The figure shows that after 40 minutes, the humidity reading differs 0.2 %RH from the final reading.
Chapter 4 ________________Instructions for the Calibration of Humidity Instruments In the following example, the transportation temperature of the calibrator (without the LiCl) is +5 °C; the calibrator is then transferred into room temperature. After this, an HMP233 probe that has been stored at room temperature, is inserted into a suitable hole of the NaCl salt chamber. The figure shows that after 40 minutes, the reading differs 1.4 %RH from the final reading.
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Chapter 5 ________________________________________________ Maintenance CHAPTER 5 MAINTENANCE Depending on the frequency of use and the general operating conditions, the salt solutions maintain their characteristics for 6 … 12 months. After that, they must be replaced. A visual check should be performed at intervals of 2 … 3 months. There must be a minimum of approximately 10% of undissolved salt at the bottom of the chamber (max. 90 %) and the salt must be clean, otherwise it must be reprepared.
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Chapter 6 ____________________________________Spare Parts and Accessories CHAPTER 6 SPARE PARTS AND ACCESSORIES Order code 19728HM 25130HM 19729HM 19730HM 19731HM 19732HM 19746HM 19766HM 19767HM 211302SP HM27032 Description Mercury thermometer with calibration certificate Thermometer with red capillary liquid Ready-dosed LiCl salt package with calibration certificate Ready-dosed MgCl2 salt package with calibration certificate Ready-dosed NaCl salt package with calibration certificate Ready-dosed K2S
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Chapter 7 _______________________________________________ Technical Data CHAPTER 7 TECHNICAL DATA Operating temperature range NOTE +0 ... +50 ºC If the LiCl solution is used or stored in temperatures below +18 ºC, its equilibrium humidity changes permanently. Accuracy: lithium chloride LiCl magnesium chloride MgCl2 natrium chloride NaCl potassium sulphate K2SO4 *) ±1.0 %RH + Greenspan's uncertainty* ±1.0 %RH + Greenspan's uncertainty* ±1.4 %RH + Greenspan's uncertainty* ±1.
User's Guide ________________________________________________________ Response time (probe and calibrator at the same temperature) with Vaisala sensors typically 10 min (deviation of the final value < ±1 %RH) Accuracy of the thermometer: with mercury ±0.
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