CN219222825U

CN219222825U - Electric heating device for water collecting disc of cooling tower and cooling tower

Info

Publication number: CN219222825U
Application number: CN202220812225.7U
Authority: CN
Inventors: 王雷; 郭长发; 杨琦; 沈冬冬
Original assignee: East China Architectural Design and Research Institute Co Ltd
Current assignee: East China Architectural Design and Research Institute Co Ltd
Priority date: 2022-03-31
Filing date: 2022-03-31
Publication date: 2023-06-20
Anticipated expiration: 2032-03-31

Abstract

The utility model discloses an electric heating device for a water collecting disc of a cooling tower and the cooling tower. The electric heating device comprises a heater and a controller, wherein the heater comprises a metal heating rod and a water level monitoring terminal, and is integrally and fixedly arranged in a water collecting disc of the cooling tower; the controller comprises a main control unit, a water temperature control unit connected with the main control unit, an anhydrous power-off secondary unit and an overheat protection secondary unit which are connected with the water temperature control unit and are connected in parallel, and a heating operation unit connected with the anhydrous power-off secondary unit and the overheat protection secondary unit, and further comprises an intermediate relay KA5 and a contactor KM1. The heating is stopped without water, so that the electric heating rod is ensured not to be exposed outside the water level.

Description

Electric heating device for water collecting disc of cooling tower and cooling tower

Technical Field

The utility model relates to the field of buildings, in particular to an electric heating device for a water collecting disc of a cooling tower and the cooling tower.

Background

In the cooling system of the building water-cooled chiller and the unitary air conditioner, it is necessary to use cooling water. From the requirements of water saving and energy saving, the cooling water system must be recycled. Cooling towers are an important part of a recirculating cooling water system. Because of the winter refrigeration demands in high-grade hotels, businesses, hospitals and the like, electric heating is usually arranged in the water collecting tray or the water collecting pool so as to prevent the water storage in the water collecting tray or the water collecting pool under the cooling tower from being frozen to influence the operation.

The electric heating of the water collecting tray of the cooling tower for the building is heated by adopting a group of electric heating rods. The control requirement on electric heating in the building electric design is reserved for the manufacturer to complete, and the design only provides a power supply for distribution. The electric heating rod is necessary for non-cooling tower product standard, and is often purchased separately by cooling tower manufacturers, and the electric heating rod lacks necessary electric control requirements. This often results in a lack of design for electrical control of the electrical heating. In practical engineering, the circuit design of secondary distribution is simple, the phenomenon of dry burning of the heater device occurs, and the circuit control is not provided with a servo wiring for preventing overheating. Even if there is the measure of preventing anhydrous dry combustion method, also adopt the water level buoy to control the closing of heater, the floater water level switch has increased the link of control, has reduced the fail safe nature of circuit, and simultaneously, the floater is undulant great about collecting the water surface of water dish, forms the frequent start and stop of heater and arouses the damage of electric control easily. In the start-up of the heating device, there is a case where the outdoor air temperature is used for control, resulting in the start-up of the electric heating device in a non-operating state of the non-cooling tower.

In the distribution of electrical heating devices for cooling tower water collection trays, conventional electrical designs simply provide power and lack the necessary design for their control. This lack of design depth of unreasonable design often creates a fire hazard for cooling towers.

Disclosure of Invention

The utility model aims to solve the technical problem of providing an electric heating device for a water collecting disc of a cooling tower, which comprises a heater and a controller, wherein the heater comprises a metal heating rod and a water level monitoring terminal, and is integrally and fixedly arranged in the water collecting disc of the cooling tower; the controller comprises a main control unit, a water temperature control unit, a water-free power-off secondary unit, an overheat protection secondary unit, a heating operation unit, an intermediate relay KA5 and a contactor KM1, wherein the water temperature control unit is connected with the main control unit; the metal heating rod and the water level monitoring terminal are connected to the non-water power-off secondary unit; the intermediate relay KA5 is connected to the non-water outage secondary unit and controls the heating operation unit, the contactor KM1 is connected to the heating operation unit and controls the main unit, when the water level monitoring terminal is separated from water, the non-water outage secondary unit is disconnected, the intermediate relay KA5 is powered off, the heating operation unit is powered off, the contactor KM1 is powered off, and the main control unit is powered off; when the water level monitoring terminal is in a submerged state, the non-water outage secondary unit is conducted, the intermediate relay KA5 is electrified, the normally open contact of the heating operation unit KA5 is closed, the contactor KM1 is electrified, and the main control unit works.

Optionally, the water temperature control unit further comprises an intermediate relay KA1, an intermediate relay KA3 and an intermediate relay KA4, wherein the intermediate relay KA3 and the intermediate relay KA4 are connected into the water temperature control unit and control the intermediate relay KA1, and the intermediate relay KA1 further controls the anhydrous power-off secondary unit and the overheat protection secondary unit which are connected in parallel; when the temperature is lower than the low-temperature threshold value, the normally open contact of the intermediate relay KA3 is closed, the normally closed contact of the intermediate relay KA4 is closed, the intermediate relay KA1 is electrified, the normally open contact of the intermediate relay KA1 is locked, and the normally open contact of the intermediate relay KA1 is closed; when the temperature is not lower than the low temperature threshold value and not higher than the high temperature threshold value, the normally open contact of the intermediate relay KA3 is opened, the normally closed contact of the intermediate relay KA4 is closed, the intermediate relay KA1 is still electrified due to locking, and the normally-on state of the intermediate relay KA1 is kept unchanged; when the temperature is higher than the high temperature threshold value, the normally open contact of the intermediate relay KA3 is opened, the normally closed contact of the intermediate relay KA4 is opened, the intermediate relay KA1 is powered off, the normally open contact of the intermediate relay KA1 is opened, and the heater is forced to stop running

In order to solve the problems, the utility model provides a cooling tower, which comprises a water collecting disc and an electric heating device for heating the water collecting disc, wherein the electric heating device comprises a heater and a controller, the heater comprises a metal heating rod and a water level monitoring terminal, and the whole heater is fixedly arranged in the water collecting disc of the cooling tower; the controller comprises a main control unit, a water temperature control unit, a water-free power-off secondary unit, an overheat protection secondary unit, a heating operation unit, an intermediate relay KA5 and a contactor KM1, wherein the water temperature control unit is connected with the main control unit; the metal heating rod and the water level monitoring terminal are connected to the non-water power-off secondary unit; the intermediate relay KA5 is connected to the non-water outage secondary unit and controls the heating operation unit, the contactor KM1 is connected to the heating operation unit and controls the main unit, when the water level monitoring terminal is separated from water, the non-water outage secondary unit is disconnected, the intermediate relay KA5 is powered off, the heating operation unit is powered off, the contactor KM1 is powered off, and the main control unit is powered off; when the water level monitoring terminal is in a submerged state, the non-water outage secondary unit is conducted, the intermediate relay KA5 is electrified, the normally open contact of the heating operation unit KA5 is closed, the contactor KM1 is electrified, and the main control unit works.

The structure is provided with a water level linkage function, is a protective measure for preventing the heater from being burned, ensures that the electric heating rod can be installed in water to run, and ensures that the electric heating rod cannot be exposed outside the water level once the electric heating rod leaves water and needs to be cut off, namely, no water stops heating. This control mode of the electric heating device is not controlled by installing an independent water level switch, and concerns whether water exists when the electric heating rod is electrified.

Furthermore, the setting temperature overheat protection function is also an optimization function of the device. The overheating protection of the body of the electric heating rod can also prevent the electric heating rod from being burned dry. When the electric heating rod is immersed in water, the temperature rise is fast, the temperature is one of three factors of fire combustion, the overheating problem of the electric heating rod needs to be timely judged, and the power supply is forced to be automatically turned off.

Drawings

Fig. 1 is a block diagram showing a heater in an electric heating apparatus for a water collecting tray of a cooling tower according to an embodiment of the present utility model.

Fig. 2 is a diagram showing an electrical control structure of a controller in an electric heating apparatus for a water collecting tray of a cooling tower according to an embodiment of the present utility model.

FIG. 3A is a schematic diagram of a main circuit for supplying power to a heater in an electric heating apparatus for a water collection tray of a cooling tower according to an embodiment of the present utility model;

FIG. 3B is a drawing showing the external terminal pattern of the heater of the electric heating device for the water collection tray of the cooling tower according to an embodiment of the present utility model;

FIG. 3C is a drawing showing the external terminal pattern of a heater in an electrical heating apparatus for a cooling tower water collection tray, in accordance with one embodiment of the present utility model;

fig. 3D is a schematic diagram of a controller in an electric heating apparatus for a cooling tower water collection tray according to an embodiment of the present utility model.

Detailed Description

The electric heating device for the water collecting tray of the cooling tower and the specific embodiments of the cooling tower provided by the utility model are described in detail below with reference to the accompanying drawings.

The electric heating device for the cooling tower water collecting tray comprises a heater and a controller. Fig. 1 is a block diagram showing a heater 10 in the above-mentioned electric heating apparatus, including a base 18, a metal heating rod 11, and a water level monitoring terminal 12. In this embodiment, the heater 10 is shown mounted in a transverse orientation in the water collection tray 19 of the cooling tower. The base 18 is used for installing the metal heating rod 11, and the controller of the electric heating device can be arranged in the base or can be externally arranged. In this embodiment, the water level monitor terminal 12 is a conductive ring disposed on the base 18. In other embodiments, the water level monitoring terminal 12 may alternatively be a metal housing on a base, or a conductive device separately provided on a side wall of the water collecting tray 19, and may be mounted in a longitudinal manner. The water level monitoring terminal 12 is a conductive ring provided on the base 18, which has an advantage of accurately monitoring the water level in the water collecting tray 19. This structure detects not the absolute water level but the relative position of the water level and the heater 10. Therefore, the electric heating device and the cooling tower adopting the device can generate signal change under the condition that the water level is lower than the base 18 and a certain distance is kept from the metal heating rod 11, and the metal heating rod 11 is prevented from being exposed in the air to generate fire hidden danger as long as the heater 10 is correctly installed without calibrating the alarm water level of the water collecting disc 19 on site by workers during construction. And even if the heater is detached or damaged, the normal operation of the structure is not affected.

As an embodiment of the present utility model, the heater 10 of the electric heater device is resistive, and it is necessary to consider three-phase balance and employ a waterproof thermistor, and the insulation resistance should be above 5mΩ (when cold) at DC 500V. The withstand voltage of the electric heating rod is AC1500V/min (when cold).

Fig. 2 is a diagram showing an electrical control structure of the controller 20 according to the present utility model, the controller 20 includes a main control unit 201, a water temperature control unit 206 connected to the main control unit 201, an anhydrous power-off secondary unit 203 and an overheat protection secondary unit 204 connected to the water temperature control unit in parallel with each other, and a heating operation unit 202 connected to the anhydrous power-off secondary unit 203 and the overheat protection secondary unit 204. An optional manual control unit 207 is connected in series between the water temperature control units 206 connected to the main control unit 201.

Fig. 3A to 3D show a circuit structure of an embodiment of the controller 20 according to the present utility model, wherein fig. 3A is a main circuit diagram of a heater in an electric heating device for a water collecting tray of a cooling tower according to an embodiment of the present utility model; FIG. 3B is a drawing showing the external terminal pattern of the heater of the electric heating device for the water collection tray of the cooling tower according to an embodiment of the present utility model; FIG. 3C is a drawing showing the external terminal pattern of a heater in an electrical heating apparatus for a cooling tower water collection tray, in accordance with one embodiment of the present utility model; fig. 3D is a schematic diagram of a controller in an electric heating apparatus for a cooling tower water collection tray according to an embodiment of the present utility model.

With continued reference to fig. 3A to 3D, a water temperature control unit 206 is connected to the heater 10 for automatically turning on or off heating according to the water temperature. The anhydrous power-off secondary unit 203 and the overheat protection secondary unit 204 which are connected in parallel with each other are connected with the water temperature control unit 206 and the heating operation unit 202, and the heating operation unit 202 starts the heater 10 only when the anhydrous power-off secondary unit 203 and the overheat protection secondary unit 204 are turned on, and otherwise, the heater 10 is turned off to avoid dry heating.

With continued reference to fig. 3A to 3D, the water temperature control unit 206 is configured to limit an operation temperature range of the heater.

As an embodiment of the present utility model, the water temperature control unit 206 further includes an intermediate relay KA1, an intermediate relay KA3, and an intermediate relay KA4, where the intermediate relay KA3 and the intermediate relay KA4 are connected to the temperature control unit and control the intermediate relay KA1, and the intermediate relay KA1 further controls the anhydrous power-off secondary unit and the overheat protection secondary unit connected in parallel to each other; when the temperature is lower than the low-temperature threshold value, the normally open contact of the intermediate relay KA3 is closed, the normally closed contact of the intermediate relay KA4 is closed, the intermediate relay KA1 is electrified, the normally open contact of the intermediate relay KA1 is locked, and the normally open contact of the intermediate relay KA1 is closed; when the temperature is not lower than the low temperature threshold value and not higher than the high temperature threshold value, the normally open contact of the intermediate relay KA3 is opened, the normally closed contact of the intermediate relay KA4 is closed, the intermediate relay KA1 is still electrified due to locking, and the normally-on state of the intermediate relay KA1 is kept unchanged; when the temperature is higher than the high temperature threshold value, the normally open contact of the intermediate relay KA3 is opened, the normally closed contact of the intermediate relay KA4 is opened, the intermediate relay KA1 is powered off, the normally open contact of the intermediate relay KA1 is opened, and the heater is forced to stop running.

As an embodiment of the present utility model, the low temperature threshold is 3 ℃ and the high temperature threshold is 15 ℃. That is, the water temperature control unit 206 includes an intermediate relay KA1, an intermediate relay KA3, and an intermediate relay KA4, the intermediate relay KA3 and the intermediate relay KA4 are connected to the water temperature control unit 206, and control the intermediate relay KA1, and the intermediate relay KA1 further controls the anhydrous power-off secondary unit 203 and the overheat protection secondary unit 204 connected in parallel to each other. For example, when the temperature is lower than 3 ℃, the intermediate relay KA3 is electrified and conducted, and the intermediate relay KA4 is not electrified; when the temperature is higher than or equal to 3 ℃ and not higher than 15 ℃, the intermediate relay KA3 is not electrified, and the intermediate relay KA4 is not electrified; when the temperature is higher than 15 ℃, the intermediate relay KA3 is not electrified, and the intermediate relay KA4 is electrified and conducted. When the temperature is lower than 3 ℃, the normally open contact of the intermediate relay KA3 is closed, the normally closed contact of the intermediate relay KA4 is closed, the intermediate relay KA1 is electrified, and the normally open contacts of the anhydrous power-off secondary unit 203 and the overheat protection secondary unit 204 which are connected in parallel are controlled to be closed.

With continued reference to fig. 3A-3D, the uninterruptible power supply secondary unit 203 includes an intermediate relay KA5. The intermediate relay KA5 is conductive, and the heating equipment operates under the condition that the normally open contact of the intermediate relay KA5 is closed. Likewise, when the intermediate relay KA5 of the anhydrous power-off control unit is conductive and the normally open contact of the intermediate relay KA5 is closed, the heating device operates. When the temperature is higher than 15 ℃, the normally open contact of the intermediate relay KA3 is opened, the normally closed contact of the intermediate relay KA4 is opened, the intermediate relay KA1 is powered off, the normally open contacts of the anhydrous power-off secondary unit 203 and the overheat protection secondary unit 204 which are connected in parallel are controlled to be opened, and the heating equipment is forced to stop running. Through the cooperative work of the intermediate relay KA1, the intermediate relay KA3 and the intermediate relay KA4, the aim of automatic control according to temperature change is achieved.

With continued reference to fig. 3A-3D, the water-free power outage secondary unit 203 includes an intermediate relay KA5, and a contactor KM1. The intermediate relay KA5 is connected to the anhydrous power-off secondary unit 203, and after the anode and the cathode of the insulated metal of the equipment are separated from water, namely, the water level monitoring terminal 12 is separated from water, the anhydrous power-off secondary unit 203 is disconnected, the intermediate relay KA5 is powered off, the heating operation unit 202 is powered off, the contactor KM1 is powered off, and the main control unit 201 is powered off; when the insulated metal anode and cathode of the device are immersed in water, namely, the water level monitoring terminal 12 is immersed in water, the non-water outage secondary unit 203 is conducted, the intermediate relay KA5 is electrified, the normally open contact of the heating operation unit KA5 is closed, and the KM1 contactor unit is electrified and is in a controllable operation state. The water level linkage function is a protective measure for preventing the heater 10 from dry heating, ensures that the electric heating rod can only operate after being installed in water, and ensures that the electric heating rod cannot be exposed outside the water level when the electric heating rod leaves water and needs to be powered off, namely, no water stops heating. This control mode of the electric heating device is not controlled by installing an independent water level switch, and concerns whether water exists when the electric heating rod is electrified.

The overheat protection secondary unit 204 includes a waterproof thermistor (not shown) provided on the heater 10, and its insulation resistance should be 5mΩ or more (when cold) at a DC 500V. Heating is stopped when a set temperature (for example, 100 ℃) is exceeded, and dry burning is prevented.

The temperature overheat protection function and the low-temperature starting function are also an optimization function of the device. The overheating protection of the body of the electric heating rod can also prevent the electric heating rod from being burned dry. When the electric heating rod is immersed in water, the temperature rise is fast, the temperature is one of three factors of fire combustion, the overheating problem of the electric heating rod needs to be timely judged, and the power supply is forced to be automatically turned off. The servo wiring for preventing overheat should not work alone in order to prevent new problems from being caused in circuit control. The function should also be of the top priority level. The low-temperature starting function is to control the design to judge that the power supply of the electric heating rod can be started when the water temperature is lower than 3 ℃. The temperature sensor should not adopt the collection mode of ambient air temperature, and the medium of heating is water rather than air environment, needs to distinguish with the temperature in the water, and is more true, reliable like this. It does not need to set automatic linkage starting, and can adopt artificial judgment to confirm again. This is because the cooling tower water collection tray is heated only to meet the water condition that the water collection tray is not frozen, and the water temperature naturally rises once the circulating cooling water system is operated. Only the initial operation stage of the cooling tower needs to prevent the water in the water collecting disc from freezing to influence the functions.

With continued reference to fig. 3A to 3D, the controller 20 further includes a manual control unit 207 between the main control unit 201 and the heating operation unit 202, for manual switching on. The manual control unit 207 includes a manual switch and an intermediate relay KA2. When the manual switch is at the automatic operation position, the temperature controller respectively controls the electrified conduction of the intermediate relays KA3 and KA4 according to the current water temperature and voltage comparison unit in the cooling tower. When the manual switch is at the manual control position, the starting button SB2 is pressed, the intermediate relay KA2 is electrified, and is locked through a KA2 normally open contact, the heating circuit is conducted, and the heating equipment operates. And then the stop button SB1 is pressed, the intermediate relay KA2 is powered off, the KA2 locking node is disconnected, and the heating equipment stops running.

The foregoing is merely a preferred embodiment of the present utility model and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present utility model, which are intended to be comprehended within the scope of the present utility model.

Claims

1. An electric heating device for a cooling tower water collection tray, comprises a heater and a controller, and is characterized in that: the heater comprises a metal heating rod and a water level monitoring terminal, and is integrally and fixedly arranged in the water collecting disc of the cooling tower;

the controller comprises a main control unit, a water temperature control unit, a water-free power-off secondary unit, an overheat protection secondary unit, a heating operation unit, an intermediate relay KA5 and a contactor KM1, wherein the water temperature control unit is connected with the main control unit;

the metal heating rod and the water level monitoring terminal are connected to the non-water power-off secondary unit;

the intermediate relay KA5 is connected to the non-water outage secondary unit and controls the heating operation unit, the contactor KM1 is connected to the heating operation unit and controls the main unit, when the water level monitoring terminal is separated from water, the non-water outage secondary unit is disconnected, the intermediate relay KA5 is powered off, the heating operation unit is powered off, the contactor KM1 is powered off, and the main control unit is powered off; when the water level monitoring terminal is in a submerged state, the non-water outage secondary unit is conducted, the intermediate relay KA5 is electrified, the normally open contact of the heating operation unit KA5 is closed, the contactor KM1 is electrified, and the main control unit works.

2. The device according to claim 1, wherein the water temperature control unit further comprises an intermediate relay KA1, an intermediate relay KA3 and an intermediate relay KA4, the intermediate relay KA3 and the intermediate relay KA4 are connected to the water temperature control unit and control the intermediate relay KA1, and the intermediate relay KA1 further controls the anhydrous power-off secondary unit and the overheat protection secondary unit which are connected in parallel with each other;

when the temperature is lower than the low-temperature threshold value, the normally open contact of the intermediate relay KA3 is closed, the normally closed contact of the intermediate relay KA4 is closed, the intermediate relay KA1 is electrified, the normally open contact of the intermediate relay KA1 is locked, and the normally open contact of the intermediate relay KA1 is closed;

when the temperature is not lower than the low temperature threshold value and not higher than the high temperature threshold value, the normally open contact of the intermediate relay KA3 is opened, the normally closed contact of the intermediate relay KA4 is closed, the intermediate relay KA1 is still electrified due to locking, and the normally-on state of the intermediate relay KA1 is kept unchanged;

when the temperature is higher than the high temperature threshold value, the normally open contact of the intermediate relay KA3 is opened, the normally closed contact of the intermediate relay KA4 is opened, the intermediate relay KA1 is powered off, the normally open contact of the intermediate relay KA1 is opened, and the heater is forced to stop running.

3. The apparatus of claim 2, wherein the low temperature threshold is 3 ℃ and the high temperature threshold is 15 ℃.

4. The apparatus of claim 2, wherein the controller further comprises a manual control unit connected in series between the main control unit and the water temperature control unit.

5. The apparatus of claim 4, wherein the manual control unit comprises a manual switch and an intermediate relay KA2, wherein the manual switch is in a manual control position, the start button SB2 is pressed, the intermediate relay KA2 is electrified and is blocked by a normally open contact of the intermediate relay KA2, the heating circuit is turned on, and the heating device operates; when the stop button SB1 is pressed, the intermediate relay KA2 is powered down, the KA2 locking node is opened, and the heating circuit is closed.

6. The apparatus of claim 1, wherein the heater comprises a base for mounting a metal heating rod, and the water level monitoring terminal is a conductive ring or a metal housing provided on the base.

7. The apparatus of claim 1 wherein the heater is positioned transversely in the cooling tower water collection tray.

8. A cooling tower comprising a water collection tray, and an electrical heating device for heating the water collection tray, the electrical heating device comprising a heater and a controller, characterized in that:

the heater comprises a metal heating rod and a water level monitoring terminal, and is integrally and fixedly arranged in the water collecting disc of the cooling tower;