Mounting Instructions for Pre-insulated Pipeline Connection
These specifications are valid for its own montage realisation of pre-insulated pipeline systems, i.e. for the working temperatures 130 °C and 180 up to 300 °C, and they are a part of each delivery of above mentioned pre-insulated systems.
1. The pre-insulated pipeline for warm-water, hot-water steam distribution systems are produced in basic dimensions ranges.
2. The branches, fixed points, compensators etc. are in standard dimensions, they can be solved eventually according to real projects of pipe networks.
3. Connecting of particular parts is made with the help of couplings.
Connecting of particular parts – installation of a coupling
On the basic version, i.e. the protection pipe HD-PE, connecting is made as follows:
a) For PIP 130
The particular coupling body is slid on side before connecting of two pre-insulated parts, i.e. on one of the part being connected. The coupling body is welded lengthways and provided with the filling opening with the diameter of 25 mm, which serves for final foaming of the joint.
After completion of welding and making of subsequent tests (the pressure, ultrasonic, eventually X-ray test) the actual installation of couplings may be done.
||If a time delay between welding and subsequent realization of the actual joint occurs, the connection point must be protected against entering of humidity, eventually of mechanical impurities and the like with appropriate material, e.g. to enwind the connection point with a microtene foil and to secure with adhesive tape on the protection pipes. This protection is necessary at pre-insulated pipelines for steam distribution systems!!! The same principle stands for systems equipped with monitoring device.
The coupling is pulled over the joint so that its opening is up and the coupling covers both ends of the protection pipes evenly.
In principle two procedures are possible:
a) The joint is finally foamed and consequently sealing of the coupling body with a contractible PE band is made (e.g. DualSeal - Raychem).
b) Reverse procedure – the joint is sealed with contractible sleeves first and is finally foamed consequently.
The essential difference in use of these variants consists in that if we realize the joint according to the procedure b), the coupling is to be kept not finally foamed for about 24 hours so that the contractible sleeves achieve sufficient strength and no sleeve tearing off by pressure of PUR in foaming occurs.
The actual procedure is evident from the following picture part.
Final foaming of joint:
It is performed with PUR foam consisting of components "A" and "B", which are measured out according to pipeline dimensions and are a part of delivery of PIP. These components will be poured together into agitating container and will be thoroughly shaken. With shaking must be achieved a homogenous mixture. So agitated mixture will be poured into the coupling body through the filling opening.
After hardening of the foam (after 15 up to 20 minutes) the fin will be cut off and the opening will be overlapped (working procedure is the same as at sleeves).
||In the course of work with PUR foam safety regulations must be observed.
Reaction of PUR is noticeably affected by temperature conditions, i.e. temperature of the components "A" and "B", in real use it must be in the range of 19 up to 21 °C. The coupling body is to be preheated in colder weather, too. Not observing of these temperatures results in eventual final non-foaming of the coupling.
Installation company must secure observing of required conditions, inclusive of requirements of foamed space, which must be dry and without mechanical impurities.
b) Performance of the joint of PIP 180 up to 300
The pre-insulated pipeline end is different from the conventional version, i.e. PUR insulation overlaps the inner insulating layer (mineral one) in thickness of 20 - 25 mm.
The difference in comparison with PIP 130 consists in use of casing made of mineral insulation; this casing is inserted as the first insulating layer.
In initial stage, from the bushing there will be cut off a part, which corresponds to a part being jointed with length, elongated by 1 - 2 cm for tighter execution of the joint. Subsequently, the bushing will be divided in two halves lengthways.
||The surface, where the inserted mineral bushing will bear, must be plain!!! Both halves of inserted bushing of inner insulating layer must be divided crosswise into cone (45°) in two parts by reason of inserting into space, which is created by removal of PUR insulation!!!
The bushing will be set on the medium-conducting pipe and will be secured with the delivered adhesive tape (on edges and in the middle), subsequently also the longitudinal joints of mineral bushing will be sealed up.
The subsequent procedure is identical with realization of the joint PIP 130.
c) Performance of the joint of PIP 180 up to 300, when the pre-insulated pipeline is equipped with monitoring system (alarm system)
The wires of the monitoring system (Brandes) are marked und foamed in the inner circumference of the protection pipe.
The layer PUR overlapping the mineral bushing must be carefully removed (cut out) at installing so that no damage of mineral bushing occurs.
The couplings in basic version can be replaced with contractible couplings of Company Raychem construction. In comparison with longitudinal welded couplings they consist of one piece-muff (except patches for filling openings). This one will be slid on one of the pipes before welding of pipelines; subsequently it will be evenly pulled over both pipeline ends and will be firmly jointed with the protection pipe by heating-up. The subsequent foaming is similar to previous procedures.
|Contractible coupling of the Company Raychem|