Dry burning protection safety device of liquid electric heater

Abstract

The utility model provides a dry burning protection safety device for a liquid electric heater, which relates to the technical field of electrical equipment and comprises a liquid boiling type temperature controller provided with more than one normally closed terminal used for being connected with an electric heating element. The liquid boiling type temperature controller further comprises a quick action diaphragm box filled with liquid, the quick action diaphragm box comprises a diaphragm capable of being deformed in an agitating mode, and when the quick action diaphragm box senses that the temperature changes, the diaphragm acts to open the normally-closed terminal so as to enable the electric heating element to stop working. The quick action diaphragm capsule is connected with one end of the capillary tube, the other end of the capillary tube extends to the electric heating element, and the capillary tube clings to and is fixedly arranged along a corresponding directrix on the surface of the electric heating element. The beneficial effects of the utility model are that when high temperature is sensed, the diaphragm acts to open the normally-closed terminal, so that the electric heating element stops working, the dry burning phenomenon is avoided, the response is rapid, and the fire hazard is avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of electrical equipment, especially a liquid electric heater dry burning protection safety device. BACKGROUND

[0002] All devices that use a heating tube to heat water, whatever the type, present a major risk: when operating without water, the heating tube will quickly overheat, turn red and reach very high temperatures before self-destruction, which can then cause a fire or the device to eventually stop working. This type of failure occurs frequently and in most cases is due to non-compliance with the installation procedures or a disruption in the water supply.

[0003] As the device manufacturers are used to wanting the water to reach its working temperature very quickly, the heating tubes always have a high surface load that will cause them to turn red almost immediately when they are no longer immersed in water. This speed of temperature rise makes detection very difficult before reaching the critical value. The use of electromechanical thermostats, which are very suitable for measuring the temperature of a liquid, cannot be used because of their thermal inertia, which causes a too long reaction time.

[0004] Another solution would be to use an electronic temperature sensor, such as a thermocouple or a thermistor with a very small volume, so that the thermal inertia is very low, but these systems, in addition to their high cost, can only measure the temperature at a specific location and can only detect a lack of water at that location. However, this location can vary depending on the installation of the water tank and is therefore unpredictable. The use of an electric heating element with a heating wire made of an alloy whose electrical resistivity increases with temperature does not solve this problem, because no alloy has a change in electrical resistance that is sufficient to avoid this catastrophic overheating.

[0005] Therefore, for all these reasons, the vast majority of devices on the market do not protect against a lack of water for the electric heating element. Another possibility would be to detect the limescale of the electric heating element, because this limescale causes the surface temperature of the electric heating element to rise by changing the efficiency of heat exchange between the liquid and the surface of the electric heating element. Finally, in systems with water circulation but without water storage, the last possibility is to use these devices to detect a drop or stop in circulation.

[0006] The purpose of the present application is to provide a simple and economical solution to these problems. SUMMARY

[0007] The utility model overcomes the defects in the prior art and provides a liquid electric heater dry burning protection safety device, which can avoid dry burning and has a rapid response.

[0008] To solve the above technical problems, the utility model is implemented by the following technical scheme:

[0009] The utility model provides a kind of liquid electric heater dry burning protection safety device, including liquid boiling temperature controller, more than one for being connected with electric heating element closed connection terminal is provided on liquid boiling temperature controller;Liquid boiling temperature controller further includes liquid filling quick action diaphragm box, quick action diaphragm box includes the diaphragm that can be encouraged deformation, when quick action diaphragm box senses temperature change, diaphragm actuates closed connection terminal to open to make electric heating element stop working;Quick action diaphragm box is connected with one end of capillary, the other end of capillary extends to electric heating element, capillary is fixedly arranged along the corresponding normal line of the surface of electric heating element.

[0010] Further, the liquid boiling temperature controller is further provided with a manual reset part, one end of the manual reset part is connected with the diaphragm, and the other end of the manual reset part is exposed outside the shell of the liquid boiling temperature controller to form a pressing end.

[0011] Further, the liquid boiling temperature controller is provided with a normally open connection terminal for being connected with an indicating part, when quick action diaphragm box senses temperature change, diaphragm actuates normally open connection terminal to close to make indicating part work.

[0012] Further, it further includes a connector, the connector has a downward opening, the inside of the opening is provided with an internal thread, and a fastener with an external thread is detachably connected to the opening through the thread; The opening is provided with a compressible sealing element, the sealing element is fixedly connected to the capillary, and the fastener is sleeved on the capillary; With the fastener being gradually tightened, the sealing element is gradually extruded to be compressed to form a seal.

[0013] Further, the upper and lower parts of the sealing element are provided with gaskets, and the gaskets are located in the opening.

[0014] Further, it further includes a fixing member for locking the capillary on the surface of the electric heating element.

[0015] Further, the fixing member is a clip or a spiral spring.

[0016] Further, the capillary is made of red copper, and the diameter of the capillary is 1.4-1.8 mm.

[0017] Compared with the prior art, the utility model has the beneficial effects that:

[0018] When the liquid in the quick-acting diaphragm box of the liquid electric heater dry burning protection safety device reaches the boiling temperature, the diaphragm is actuated to open the normally closed connection terminal, so that the electric heating element stops working, thereby avoiding the dry burning phenomenon, the reaction is rapid, and the fire hazard is avoided; in addition, the capillary is fixedly arranged along the corresponding guideline of the surface of the electric heating element, which helps to improve the sensitivity of the temperature sensing of the electric heating element at any position along the length thereof, and improve the sensitivity and timeliness of detection. BRIEF DESCRIPTION OF DRAWINGS

[0019] The accompanying drawings are used to provide further understanding of the present application, together with the embodiments of the present application, to explain the present application, and do not constitute a limitation on the present application, in which:

[0020] Figure 1 is a structural schematic view of the liquid electric heater dry burning protection safety device applied to a spiral electric heating element;

[0021] Figure 2 is a structural schematic view of the quick-acting diaphragm box;

[0022] Figure 3 is a structural schematic view of the liquid electric heater dry burning protection safety device applied to a straight pipe type electric heating element;

[0023] Figure 4 is a structural schematic view of the liquid electric heater dry burning protection safety device applied to a rod type electric heating element;

[0024] Figure 5 is a structural schematic view of the joint applied to the tank;

[0025] Figure 6 is a connection schematic view of the liquid electric heater dry burning protection safety device and the water storage cylinder;

[0026] Figure 7 is a connection position schematic view of the capillary in the liquid electric heater dry burning protection safety device when the liquid boiling type temperature controller is used to detect scale deposition around the electric heating element.

[0027] In the drawings:

[0028] 1, liquid boiling type temperature controller; 2, quick-acting diaphragm box; 3, normally closed connection terminal; 4, capillary; 5, electric heating element; 6, manual reset part; 7, normally open connection terminal; 8, joint; 9, sealing element; 10, gasket; 11, fastener; 12, pipe wall; 13, clamp; 14, straight pipe type electric heating element; 15, rod type electric heating element; 16, spiral electric heating element; 17, water storage cylinder; 18, immersion heater; 19, electric heating element surface scale. DETAILED DESCRIPTION

[0029] The preferred embodiments of the utility model are described below in combination with the drawings, and it should be understood that the preferred embodiments described herein are only used for illustrating and explaining the utility model, and are not used for limiting the utility model.

[0030] As Figures 1-2 shown, the utility model discloses a kind of liquid electric heater dry burning protection safety device, including liquid boiling type temperature controller 1, liquid boiling type temperature controller 1 includes fast-acting diaphragm capsule 2 with liquid filling, more than one normally closed terminal 3 for being connected with electric heating element 5 is provided on liquid boiling type temperature controller 1;Specifically, fast-acting diaphragm capsule 2 includes the diaphragm that can be excited to change shape, and the boiling temperature of liquid in fast-acting diaphragm capsule 2 under local vacuum is known, when reaching the boiling temperature of liquid, vapor pressure in constant temperature process suddenly causes diaphragm to bulge outward, that is, when fast-acting diaphragm capsule 2 senses temperature change, diaphragm bulging action makes normally closed terminal 3 open to make electric heating element 5 stop working.Specifically, normally closed terminal 3 is connected with fixed contact located in the inside of liquid boiling type temperature controller 1, and movable contact is also provided in the inside of liquid boiling type temperature controller 1, and in normal state, movable contact and fixed contact are connected, that is, make normally closed terminal 3 in on state;When diaphragm bulging action separates movable contact and fixed contact, so that normally closed terminal 3 is in open state, and electric heating element 5 no longer heats.

[0031] Fast-acting diaphragm capsule 2 is connected with one end of capillary tube 4, and the other end of capillary tube 4 extends to electric heating element 5, and capillary tube 4 is fixedly arranged along the corresponding line of the surface of electric heating element 5, as Figure 3 shown, electric heating element 5 has tube wall 12, in order to measure the change of surface temperature of electric heating element 5 as soon as possible, capillary tube 4 is pressed on the tube wall 12 of electric heating element 5 along the corresponding line of the surface, so that the surface is first floated from liquid according to the position of water tank when leakage or water shortage occurs;And temperature rise at any position along its length is very sensitive, and several centimeters are enough to trigger normally closed terminal 3 due to internal pressure increase caused by overheating.

[0032] As Figure 7 shown, when liquid boiling type temperature controller is used in immersion heater 18 to detect electric heating element surface scale 19 around electric heating element, capillary tube must also be wound in the hottest area.

[0033] The liquid boiling temperature controller 1 is further provided with a manual reset part 6, one end of the manual reset part 6 is connected with the diaphragm, and the other end of the manual reset part is exposed outside the shell of the liquid boiling temperature controller 1 to form a pressing end. The manual reset part 6 is a mechanical structure, the manual reset part 6 is used to push the diaphragm to reset, and the liquid boiling temperature controller 1 can be closed only after the temperature is significantly reduced and the manual reset part 6 is pressed, so that the diaphragm is reset, the movable contact and the fixed contact are reconnected, the normally closed terminal 3 returns to the closed state, and the safety is high.

[0034] The liquid boiling temperature controller 1 is provided with a normally open terminal 7 for connecting with an indicating part, when the quick-acting diaphragm box 2 senses that the temperature changes, the diaphragm is actuated to close the normally open terminal 7, so that the indicating part works, and the indicating part can be an indicating lamp or a sound alarm; similarly, the normally open terminal 7 is correspondingly connected with a movable contact inside the liquid boiling temperature controller 1, the movable contact is used in pairs with a corresponding fixed contact; in the normal state, the movable contact and the fixed contact are in a separated state; when the diaphragm is actuated, the movable contact is pushed to be connected with the fixed contact, so that the normally open terminal 7 is connected, that is, the indicating part is powered to work, so that the operator can be noticed.

[0035] As shown in Figures 5-7 , the liquid boiling temperature controller 1 must be located outside the water heater or the heat exchanger, and the capillary tube 4 extends into the liquid; the water storage cylinder 17 of the water heater or the heat exchanger has a tank wall, the tank wall is provided with a mounting port, the mounting port is inserted with a connector 8, a fixed part of the connector 8 is screwed or welded to the tank wall, and the position is usually used for installing a temperature sensing rod of a temperature sensor; the connector is small in size and can be installed on a flange or in the middle of an outlet of an immersion heater electric heating element. The connector 8 has a downward opening, the inside of the opening is provided with an internal thread, and further includes a fastener 11 with an external thread, the fastener 11 is detachably connected to the opening through the thread; the opening is provided with a compressible sealing element 9, the sealing element 9 is fixedly connected to the capillary tube 4, and the fastener 11 is slidably sleeved on the capillary tube 4; as the fastener 11 is gradually screwed, the sealing element 9 is gradually extruded to be compressed to form a seal; so that the liquid in the water heater or the heat exchanger cannot penetrate out; the fastener 11 can be a nut structure as shown in Figure 5 , and can also be fixed by using a clamp or a spiral spring, and the final purpose is to maintain sufficient sealing to provide close thermal contact between the electric heating element 5 and the capillary tube 4, that is, to avoid the heat inside the water heater or the heat exchanger from being dissipated to the outside, and to ensure the accuracy of the detection of the capillary tube 4 as much as possible, so as to obtain a fast response time.

[0036] To further enhance the sealing, a gasket 10 can also be provided above and below the seal 9, which is located in the opening and serves to press the gasket 10 and the seal 9 when the fastener 11 is tightened.

[0037] In particular, it also comprises a fixing member for locking the capillary tube 4 on the surface of the electric heating element 5; the fixing member is a clip 13 or a coil spring, which is selected and used according to the structure of different applications, and can be applied to any form of tubular armored electric heating element, such as a straight pipe type electric heating element 14 as shown in Figure 3 , a rod type electric heating element 15 as shown in Figure 4 , and a spiral type electric heating element 16 as shown in Figure 1 .

[0038] The capillary tube 4 is made of red copper, and the diameter of the capillary tube 4 is 1.4-1.8 mm, which has very low thermal inertia and thus reacts very quickly to temperature changes; the length of the capillary tube 4 is not limited and is set according to the specific structure of the electric heating element 5 to be detected.

[0039] The application adopts a liquid boiling type temperature controller 1 combined with a capillary tube 4 for temperature sensing, and any position of the capillary tube 4 can sense the temperature without heating the entire capillary tube 4, that is, any point on the capillary tube 4 can sense the temperature, thereby improving the sensitivity and timeliness of detection.

[0040] For the determination of the optimal trigger temperature, in the normal operating condition, the conventional temperature range of the water storage type or circulating type water heater, the water heater and the heat exchanger, the highest water temperature is about 80°C, but often only about 70°C. The pipe wall temperature of the electric heating element 5 is always higher than this value and varies according to the technical definition of the latter, especially its surface load and the water circulation speed of the circulating heater. The surface load of the electric heating element for water heating on the market varies from 5 W / cm 2 to 30 W / cm 2 , and the working surface temperature varies greatly. Therefore, the definition of the trigger temperature of the temperature controller must take these parameters into account to avoid false triggering due to its set point being too close to the water temperature, and too late triggering due to its set point being too high. Therefore, several calibration temperature levels are needed to cover different use conditions.

[0041] For the trigger condition, the best method is to determine the temperature by testing the finished product. Even if only a small part of the electric heating element 5 is exposed, the electric heating element surface is covered with scale 19 or sludge, it can still work normally; without water, the electric heating element 5 will be triggered immediately due to its fast heating.

[0042] It should be pointed out finally: the above is only the preferred embodiment of the utility model, and is not used to limit the utility model, although the utility model is described in detail with reference to the embodiment, for the skilled person in the art, it still can modify the technical scheme recorded in the foregoing each embodiment, or make equivalent replacement to part of technical features, but any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model should be included in the protection scope of the utility model.

Claims

1. A liquid electric heater dry-burn protection safety device, characterised in that, The liquid boiling temperature controller (1) is provided with more than one normally closed terminal (3) for connecting with the electric heating element (5); the liquid boiling temperature controller (1) further comprises a liquid-filled quick-action diaphragm capsule (2) which comprises a diaphragm capable of being excited to deform, when the quick-action diaphragm capsule (2) senses a change in temperature, the diaphragm is excited to deform to open the normally closed terminal (3) so as to stop the electric heating element (5) from working; the quick-action diaphragm capsule (2) is connected with one end of the capillary tube (4), the other end of the capillary tube (4) extends to the electric heating element (5), and the capillary tube (4) is fixedly arranged along the corresponding contour line of the surface of the electric heating element (5).

2. The liquid electric heater dry-burn protection safety device according to claim 1, wherein, The liquid boiling temperature controller (1) is further provided with a manual reset part (6), one end of the manual reset part (6) is connected with the diaphragm, and the other end of the manual reset part (6) is exposed outside the shell of the liquid boiling temperature controller (1) to form a pressing end.

3. The liquid electric heater dry-burn protection safety device according to claim 1, wherein, The liquid boiling temperature controller (1) is provided with a normally open terminal (7) for connecting with an indicating component, when the quick-action diaphragm capsule (2) senses a change in temperature, the diaphragm is excited to deform to close the normally open terminal (7) so as to make the indicating component work.

4. A liquid electric heater dry-burn protection safety device according to any one of claims 1 to 3, characterised in that, Further comprising a connector (8) having a downward opening, the inside of the opening is provided with an internal thread, and further comprising a threaded fastener (11) which is detachably connected to the opening through the thread; the opening is provided with a compressible sealing element (9), the sealing element (9) is fixedly connected to the capillary tube (4), and the fastener (11) is slidably sleeved on the capillary tube (4); as the fastener (11) is gradually tightened, the sealing element (9) is gradually extruded to be compressed to form a seal.

5. The liquid electric heater dry-burn protection safety device according to claim 4, wherein, The upper and lower parts of the sealing element (9) are provided with gaskets (10) which are located in the opening.

6. The liquid electric heater dry-burn protection safety device according to claim 4, wherein, Further comprising a fixing member for locking the capillary tube (4) on the surface of the electric heating element (5).

7. A liquid electric heater dry-burn protection safety device according to claim 6, characterised in that, The fixing member is a clip (13) or a spiral spring.

8. The liquid electric heater dry-burn protection safety device according to claim 1, wherein, The capillary tube (4) is made of red copper, and the diameter of the capillary tube (4) is 1.4-1.8 mm.

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