User manual VAISALA HMK15

[. . . ] 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. Please observe that this manual does not create any legally binding obligations for Vaisala towards the customer or end user. All legally binding commitments and agreements are included exclusively in the applicable supply contract or Conditions of Sale. ___________________________________________________________________ Table of Contents CHAPTER 1 GENERAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] Rinse and dry the cup after every use. LiCl MgCl2 NaCl K2SO4 15 g or 18 ml 30 g or 30 ml 20 g or 15 ml 30 g or 20 ml 14 _____________________________________________________M210185EN-C Chapter 3 _____________________________________Preparing the Salt Solutions 0606-167 Figure 4 4. Sprinkle a correct dose of salt into the chamber stirring constantly When all salt has been sprinkled into the chamber, the saturated salt solution should have the ratio of 60 . . . Close the chamber with the chamber cover (Figure 5). 5. VAISALA _________________________________________________________15 User's Guide ________________________________________________________ 0606-168 Figure 5 6. 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. 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. 5 mm and the third step for the 18. 5 mm hole. Keep the holes always closed when not calibrating. Write the preparation date on a sticker and mark the chamber with it. If you use a ready-dosed salt package, use the sticker with the batch code. Mark all parts of the salt chamber (chamber, chamber cover and transit cover) with stickers. This way, various covers and different salts do not get mixed. 16 _____________________________________________________M210185EN-C Chapter 3 _____________________________________Preparing the Salt Solutions 0606-169 Figure 6 8. Mark the chamber and covers with stickers Allow approximately 24 hours for stabilization before use so that the salt solution reaches the equilibrium humidity. See Chapter 5 Maintenance on page 31 on how to maintain the salt solutions. 9. NOTE If you do not use the instrument for a longer period of time, close the chambers with transit covers. VAISALA _________________________________________________________17 User's Guide ________________________________________________________ This page intentionally left blank. 18 _____________________________________________________M210185EN-C 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. The more the transportation or process temperatures differ from the temperature at the calibration site, the longer the stabilization time required. In laboratory use, the calibrator should be stored in that part of the room where the temperature is most stable. The calibrator must be kept out of direct sunlight and away from localized heat sources, such as spot lights, heaters and soldering irons. If the probe/transmitter is checked against several humidity references, the checking must first be made at the dry end. More detailed instructions are given in individual manuals of transmitters and probes. Do not hold the salt chamber or other parts of the calibrator in hand during calibration as they warm up and cause errors in the readings. VAISALA _________________________________________________________19 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. 1 cm Thermometer Saturated salt solution Undissolved salt 20 _____________________________________________________M210185EN-C 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. The mercury thermometer has been calibrated at five points and the result is traceable to the Measurement Standards Laboratory of the Centre for Metrology and Accreditation in Finland. For more accurate results, use the corrections given in the calibration certificate or their interpolated values. [. . . ] - 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. 5 mm and the third step for the 18. 5 mm hole. - Clean the transit covers with a damp cloth and press them on vacant chamber holders. - Take the thermometer off the holder, turn the sleeve the other way round and perform the calibration according to section Calibration on page 23. [. . . ]