(1) Choose the cable type according to power supply condition and power net load ,decide if use parallel connection or series connection type cables, single phase or three phase type cables. Generally, series connection type cables are used on long pipes. For pipe net system, constant wattage three phase type cables are suitable, if pipes are shorter, constant wattage single phase type cables are suitable.
(2) Decide the cable type i.e. wattage per meter,according to the highest process temperature of media in pipe.
(3) Calculate the total length of electric heating cables needed according to total heat loss of pipes or tanks and the chosen power per meter. As pipes have bends, valves and brackets, the length to be ordered should add 5%~10%.
(4) According to applying locations select cable type: reinforced type shall be used for sea shore, sea platforms, underground or corrosive locations.
(5)Based on the max usage length of the heating cable, divide the pipeline into certain number of sub systems of electrical accompanying heating.Each sub system must contain at least one power connection box,one temperature controlling system and a certain number of two-way,tree-way junction boxes and terminal junction boxes.For terminal boxes use as many boxes as there are heating belt at the terminal end.
(6) Circumvent the flange,the left length of cable is 0.5m, 0.8m to butterfly valve and ball valve respectively. About pipe valve,not congting overtime. The left length is : to the wires with junction box, it is 2 meters of the box.
(7) Alumina Adhesive tape: calculate the required quantity by multiplying the actual length of heating belt with 1.2 and make sure the quantity ordered is a round number of times of 45meters.
(8) Heat resistance adhesive tape:calculate the required quantity with the equation below and be sure to order a round number of times of 20 meters.
L1=2.5D×L×（n+1.8）………… (3-5)
herinto：
D-external diameter of the pipeline in m
L-total length of the accompanying heating belt in m
N-number of acconmpanying heating belt laid parallel with each pipeling
Calculate the require quantity by multiplying the actual length of heating belt with 0.8.
(9) Fasteners:
Two set for Power box,two-way and three-way box,temperature Controller; One set for terminal box.
(10) Maine Glue:0.5Kg for each junction box of underground pipes.
(11) Explosion Proof Daub:About 0.2Kg for load cable laying in stee tube |
