– Valid for Germany –
Identification and marking of existing immersion sleeves with lengths up to 60 mm
1. General
In accordance with the calibration requirements for Germany (PTB - Technical Guidelines K8 + K9) for the use of immersion sleeves, these must be tested for conformity exclusively with the temperature sensors used.
In the event of a replacement during the periodic change (calibration exchange) of temperature sensors and the operation of existing immersion sleeves up to and including 60 mm with MID-compliant temperature sensors, the immersion sleeve must be clearly identified and marked according to the inventory list filed with the PTB.
The legal background to the marking of existing immersion sleeves, as well as the list of granted tolerances for existing immersion sleeves, can be found on the website of Working Group 7.51 of the German National Metrology Institute (PTB). This information is available under the heading "Documents".
2. Identification and verification of the dimensions of existing immersion sleeves
The thermowells are identified based on significant characteristics that can be verified in the field using measuring tools. The values have been rounded to verifiable sizes (e.g., to whole millimeters).
Procedure:
- Assignment of immersion sleeves based on construction type
- Determining the inner diameter using a diameter gauge
- Examination of the further dimensions of the assigned building type
- Identification of the immersion sleeve according to the table – asymmetric temperature sensor installation page 3 – symmetric temperature sensor installation pages 3/4
- Labeling of the nameplate with the PTB TH No.: xxx
- Attach the label to the immersion sleeve and the pipe using sealing wire and a self-locking seal.
Building types:
3. Marking the immersion sleeve with sensor
Label the thermowell with the determined PTB TH number; ideally, write on it with a waterproof pen. Attach the label to the sensor and thermowell installation location and seal it.
4. Approved existing immersion sleeves for asymmetrical sensor installation
Installation of flow temperature sensor in existing immersion sleeve, installation of return temperature sensor in the flow sensor
5. Tolerated existing immersion sleeves for symmetrical sensor installation
Installation of flow and return temperature sensors in existing immersion sleeves
Author
Quelle: Handbuch der Wärmekostenabrechnung | Frank Peters Minol Messtechnik W. Lehmann GmbH & Co. KG, 2019
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