IEC 61520 pdf download,Metal thermowells for thermometer sensors – Functional dimensions
This International Standard specifies functional dimensions for metal thermowells for thermo- meter sensors of nominal diameters ranging from 3 mm to 8 mm for use in process control.
2 Terms and definitions
For the purposes of this International Standard, the following terms and definitions apply: 2.1 thermowells protective parts machined from solid bar stock. The various types of thermowells are as follows: – type A: threaded type; – type B: extended threaded type; – type C: flanged type; – type D: weld-in type. 2.2 insertion length U portion of the thermowell which can be in contact with the medium 2.3 insertion length U 1 (differs from U only on type d thermowells) portion of the thermowell which is inserted into any means of attachment. This insertion length is usually the reference length for any stress and resonance calculations. This dimension is usually determined by the user of the thermowell 2.4 tip thickness X the minimum thickness of the well at the tip. May be “v” or “w” shaped
3.1 Type A: threaded type Figure 1 illustrates the external configuration of type A thermowells. The immersion length U may be either cylindrical or tapered.