LV13670B - Flow type electrical heater - Google Patents

Abstract

Flow type three-phase electrical heater for current-conducting liquid, comprising leak-proof grounded casing with enclosed therein at least three phasic electrodes and at least one neutral electrode and inlet and outlet pipes for the current-conducting liquid, is characterized by mutual dielectric isolation of said electrodes and said casing.

Description

ELECTRIC HEATER IN THE PIPE

The invention relates to electrical engineering, in particular to electrode-type electric heating devices, and can be applied to autonomous heating of living spaces by liquid heat carrier.

Electrode-type heaters for conductive fluids such as ordinary tap water or water with electrolyte additives such as various salts are known. Electric heaters with three-phase current are most effective. Typical technical solutions for this type of electric heaters are described in Bulgarian Patent 61590, Czech Patents 277796 and 290263 and VFR Patent 3421807. The electrode heater described in these patents is typical of electric heaters using a three-phase current, in which the the number is a multiple of three or three, and at least one zero electrode connected to a grounded heater housing. When used as heat carrier tap water or electrolyte aqueous solution, this design allows for the improvement of the uniform load distribution across the entire surface of the heater and reduces the size of the zero electrode. However, all heaters built on this principle have the common drawback: low electrical safety. In the event of a break in the neutral conductor, incorrect phase, or in the phases of the connection of the neutral conductor or voltage unbalance, a voltage dangerous to man appears on the housing of the electric heater. This deficiency is solved by using electrical heaters in industrial conditions, either electrically - with electrical and electronic safety systems, or constructively - by placing the electric heater in an insulating sheath or by making special electrodes (Russian Patent 2062960). None of these methods is satisfactory, because even when the heater housing is insulated, the heat transfer fluid, which is an electrically conductive fluid, connects the heater housing to the entire heating system. Separating the heating system from the heater with insulating short pipes or using plastic pipes does not solve the problem either.

The electrical safety problem has become particularly acute with the introduction of electrode-type electric heaters in living rooms. The use of modern special heat carriers based on water - organic component - electrolyte made it possible to simplify the design of electric heaters and reduce their size. A typical solution of this type is the Galan electrode heater (see, for example, a description at http://www.mirtepla.ru), which is taken as a prototype. However, the design principle of these heaters remains the same - the zero electrode and the housing are connected and grounded. The already known disadvantage of low electrical safety has remained.

Our goal was to develop an electrode wheel electric heater design that works with a mixture of water - an organic component - an electrolyte that does not suffer from this disadvantage.

Unexpectedly, the electrode-type electric heater designs used in practice provide productivity for domestic conditions without the heater housing as an electrode switching system. We found that placing three mutually isolated phase electrodes and one ground electrode isolated from the grounded body in the electric heater eliminates the earlier design disadvantage of appearing dangerous voltage on the heater body and incorrectly connecting the ground to the entire heating system if the ground wire breaks. and the phase conductors or phase voltage is uneven. The skilled artisan will appreciate that the number of phase electrodes and zero electrodes in a particular heater design may be proportionally increased, if necessary.

In our design, the separately grounded housing completely removes the rising voltage, for example, when a zero wire breaks, and all operating parts (electrodes) under voltage are separated from the housing. This design also has the advantage that it does not impede the application of known methods of protection against electric shock.

Claims (1)

A flow-through three-phase electric heater for a conductive fluid consisting of an airtight grounded body, with at least three phase electrodes inserted therein and at least one neutral (zero) electrode and conduits for inlet and outlet of the heat transfer fluid is different in that said electrodes are dielectric insulated with each other and with the housing.