A kind of built-in protector for electric heating tube
Technical field
The present invention relates to a kind of safety utilization of electric power protective device, relate in particular to a kind of when load is transshipped, can automatic shutdown circuit when overcurrent, short circuit built-in protector for electric heating tube.
Background technology
Existing electrical bar overheat protector is divided into recovery type electrical bar overheat protector and two kinds of the electrothermal tube overheat protectors of being with hand-reset.
Recovery type electrical bar overheat protector relates to the liquid electric heating equipment, is applicable to the overheated electronic protector of electrical heating elements of electric water boiler.Purpose is to provide a kind of overheated going up towards temperature to be lower than 200 ℃ and electrical bar can not be burnt, the fully automatic electric minor electrical bar overheat protector that can recover automatically after the outage.The protector circuit comprises temperature control switch forceful electric power loop and controllable silicon weak electrical loop, and the line bag control of the miniature relay of the output of controllable silicon weak electrical loop seals in the contact of the miniature relay in forceful electric power loop.But the cost of self is higher.
The electrothermal tube overheat protector of band hand-reset is equipped with the control contact mechanism in the housing cavity of resorption, the housing epicoele is equipped with bellows, forms temperature sensing device with the bellows handle and from the capillary that bellows prolongs away.Be wrapped in capillary on the electrothermal tube and under abnormal condition, be heated and trigger the bellows action, thereby, cut off the electrothermal tube power supply at short notice rapidly, reach the anti-dry purpose.But this overheat protector needs manually just can reset after cutting off the electricity supply, and reaches the effect of protection electrical equipment again.
The processing of electric heating tube is after in pipe, filling the magnesium powder, to carry out draw technology, makes the magnesium powder in the pipe fine and close more.In the prior art, a kind of thermal protector is arranged, patent No. ZL 200520077289.3; Patent name is a composite overflow and overheat protector, and this patent is used common enclosure, before the electric heating tube draw; Fill up the magnesium powder around the shell, behind the draw, because of the magnesium powder inwardly shrinks; Shell has been used external force, the shell of protector is deformed, protector lost efficacy.
Summary of the invention
The objective of the invention is provides a kind of built-in protector for electric heating tube in order to overcome the deficiency of prior art, at electric heating tube after the can of magnesium powder; Can not cause damage in the draw process to thermal protector; Make it highly sensitive, good reliability can be reused.
The objective of the invention is to realize like this: a kind of built-in protector for electric heating tube; The shell that comprises an end opening; The openend of shell is provided with end cap, is provided with base plate, bimetallic element, moving contact, insulator foot, static contact, static contact lead, base plate lead in the shell; One end of bimetallic element is provided with moving contact, and the other end is fixed on the base plate, is connected with the base plate lead on the base plate; Insulator foot also is set on the base plate, static contact is set in the insulator foot, an end of static contact connects fixed contact; The other end of static contact is connected with the static contact lead; The blind end and the end cap of said shell are respectively equipped with powder retaining ring, and the diameter of powder retaining ring and end cap is greater than the diameter of shell, and the powder retaining ring of closed termination of outer cover is provided with groove.
The invention has the beneficial effects as follows: the two ends of shell of the present invention are designed with powder retaining ring, in electric heating tube magnesium powder pouring process, because of the diameter of the powder retaining ring diameter greater than shell; Magnesium powder a two ends at protector; And be designed with groove on the powder retaining ring, in electric heating tube draw process, leave to enterolithic space to powder retaining ring; Thereby the function of protector is existed, reach purpose ambient temperature control.The present invention is designed for and is installed in the electric heating tube, has simple and reasonablely, and action is stable, reliable, highly sensitive, can automatically reset, and is reusable, low cost and other advantages.
Be connected with heater strip for ease, be respectively equipped with wire guide on each powder retaining ring, the base plate lead passes from a wire guide, and the static contact lead passes from another wire guide.Gap between base plate lead and the powder retaining ring is through epoxy sealing, and the gap between static contact lead and the powder retaining ring can effectively stop the magnesium powder to get into enclosure interior through epoxy sealing, has prolonged useful life of the present invention greatly.
Description of drawings
Fig. 1 is a kind of structural representation of the present invention.
Among the figure, 1 shell, 2 bimetallic elements, 3 moving contacts, 4 insulator foots, 5 powder retaining rings, 6 epoxy resin, 7 static contact leads, 8 static contacts, 9 fixed contacts, 10 base plates, 11 base plate leads, 12 grooves, 13 wire guides, 14 end caps.
Embodiment
As shown in Figure 1; Built-in protector for electric heating tube; Comprise the shell 1 of an end opening, the openend of shell 1 is provided with end cap 14, is provided with base plate 10, bimetallic element 2, moving contact 3, insulator foot 4, static contact 8, static contact lead 7, base plate lead 11 in the shell 1.
Be respectively equipped with powder retaining ring 5 on the blind end of shell 1 and the end cap 14, the diameter of powder retaining ring 5 and end cap 14 is greater than the diameter of shell 1, and the powder retaining ring 5 of shell 1 blind end is provided with two grooves 12.
One end of bimetallic element 2 is provided with moving contact 3; The other end is fixed on the base plate 10; Be connected with base plate lead 11 on the base plate 10, insulator foot 4 also is set on the base plate 10, static contact 8 is set in the insulator foot 4; One end of static contact 8 connects fixed contact 9, and the other end of static contact 8 is connected with static contact lead 7.
Be respectively equipped with wire guide 13 on each powder retaining ring 5, base plate lead 11 passes from a wire guide 13, and static contact lead 7 passes from another wire guide 13.
Gap between base plate lead 11 and the powder retaining ring 5 seals through epoxy resin 6, and the gap between static contact lead 7 and the powder retaining ring 5 seals through epoxy resin 6.