The IDT-manhole safety sealing ring and sealing tapes made from biaxial oriented MultiTex® ePTFE have been developed in order to meet the high requirements for tightness and security when using hand, head and manhole covers on boilers.
With the ban on asbestos-containing materials asbestos-free soft gaskets from various manufacturers have been developed and used for closure systems of steam boilers.
Unfortunately, some of these designs suffered serious accidents due to the squeeze out of their seat.
As a result, the VdTÜV and FDBR were forced to point out possible dangers and to develop requirements for seals for oval hand, head and manhole closures on steam boiler systems „Merkblatt Dichtung 100“.
This instruction sets out the requirements for the clamping system and the seal, specifies the test conditions and specifies the marking of the seal.
The tests are carried out by the VdTÜV.
If the result of the test is positive, the component designation is assigned, with which the component-tested seals are to be provided. After notification and transitional period, only TÜV-approved seals may be installed.
With the following objectives, IDT has developed the seal constructions shown in Figure 2 in cross-section and obtained test certificates:
Blow-out safety (corrugated ring, flare)
high level of compensation (corrugated ring)
Prevention of graphite removal by the operating medium (flange)
high aging and chemical resistance
The IDT seals fulfill the test requirements of the VdTÜV broschure „Dichtungen 100“ TRD 401, Appendix
All constructions have the following TÜV approval:
permissible operating pressure p = 40 bar
permissible operating temperature T = 250 ° C
permissible cold water test pressure p’ = 88 bar
The selection of the most effective design variant takes place according to the state of the voltage supply system.
For each seal a detailed installation and assembly instructions are included, the u. a. contains:
Requirements for the bracing system
Requirements for the gaskets
Assembly, disassembly of the seal
Specification of the tightening torque