Heating cable for plant greenhouse cultivation
The heating elements of the heating cable used in the greenhouse cultivation are usually composed of high resistance alloy materials, such as copper, nickel, chromium, aluminum, iron and other metals. A cable core wire for copper wire, the other one is the high resistance alloy wire, using single stranded or solid conductor insulation structure; the best use of available heat-resisting PVC, silane crosslinking polyethylene, two core wire placed in parallel together with heat resistance and insulation sheath; most oil resistant PVC sheath, and not contains lead, cadmium and other harmful heavy metal materials; most do not require armoured cable. The heating power of this kind of cable is arbitrary, and it is determined by the user's demand of the use of voltage, delivery length and the total heating power, which is determined by the cable section and the insulation thickness. But the cable must be complete supply, namely the end of copper alloy wire and reliable welding or crimping, injection molding and sealing head; the other end of the injection power supply connector.
Cultivated plants for greenhouse heating cable can also be used in parallel power supply cable constant power, it only need to determine the heating power to the unit of length, the user can arbitrarily cut within a certain length, the installation is very convenient. But the constant power band high cost, taking into account the cable temperature is not high, in order to reduce the cost without the use of fluorine plastic insulation, silane crosslinked polyethylene has been able to meet the temperature requirements; copper wire braided layer can be considered canceled, using wrapping copper plastic composite film instead of the same, can improve the heat dissipation but, in order to ensure the safety and can not ignore the copper wiring; sheath materials shall be selected with the same. Finally: as a heating element winding alloy wire, after several thermal cycles should not loose, otherwise it will cause local alloy wire and the current carrying wire is bad, and may even lose circuit, heating function, it needs to make proper improvements on insulation support structure.