KR101824071B1 - Induction heating and heat transfer system - Google Patents

Abstract

The present invention relates to an induction heating and heat transferring system which instantly heats a ferromagnet like iron by using an induction heating method, and transfers a heat source generated in the heated ferromagnet to quickly convert into a high temperature fluid (warm water or steam). The system comprises: a coil wound for induction heating; a bobbin provided in the coil, and fixing the wound coil; a fixed heating part vertically stacked in the bobbin for heating; a water inlet nozzle installed to vertically pass the edge of the fixed heating part, and supplying a fluid to the inside of the fixed heating part; and a rotary heat transfer part installed in the fixed heating part to spirally rotate the fluid supplied through the water inlet nozzle so that a heat source generated in the fixed heating part can be transferred to the fluid.

Description

{Induction heating and heat transfer system}

The present invention relates to an induction induction heating and heat transfer system for instantly converting a low-temperature fluid into electricity using a high temperature fluid at a desired temperature. More particularly, the present invention relates to an induction induction heating and heat transfer system, And to a induction-induced heat generation and heat transfer system capable of quickly transferring a heat source generated from a heated ferromagnet to a low-temperature fluid and quickly converting the heat source to a high-temperature fluid (hot water or steam).

In general, there are various methods (resistance method - hot wire, ceramic heater, ultrasonic, Josephson, friction method) that are used to convert low temperature fluids into high temperature fluids by using electricity.

In the conventional methods, the cold water is raised to a desired temperature within 3 seconds to 5 seconds. Due to a number of technical limitations, a certain amount of cold water is stored in the low water cistern and then the low water cistern is heated A low-water storage method in which hot water having a required temperature is supplied at a desired time is widely used.

However, this method requires a certain capacity of a reservoir and installation space for storing cold / hot water, and there is an inefficiency of continuously consuming electricity to maintain a constant temperature.

Therefore, nowadays, a method of instantaneous (3 seconds to 5 seconds) conversion of cold water to hot water by using induction induction heating method is more widely used in the low water storage method.

In the case of a non-contact instantaneous water heater, it is possible to obtain hot water of about 40 ° C within 3 seconds to 5 seconds. Depending on the capacity, the power consumption is about 2.5 kW ~ 6 kW. Increasing the voltage requires more electric energy.

The induction method generally uses a coiled induction coil in the form of a cylinder (cylindrical) to place a ferromagnetic iron (IRON) metal around the center or coil of the coil wound by an induction field, IRON is a method of heating a metal by an eddy current and then obtaining hot water at a required temperature through conduction (radiation / convection) of a heat source generated from the heated ferromagnetic material. This is because the energy efficiency And the human body is not directly exposed to the heat source or electricity, so it is a very safe method in which there is no fear of burning and electric shock compared with the conventional method.

In the current induction induction heating system, as shown in FIG. 12, the heating of the heating element is such that the ferromagnetic body 2 such as iron is positioned on the basis of the central axis around which the induction coil 1 is wound. The ferromagnetic material 2 is heated by the eddy current when the alternating magnetic field is applied to the ferromagnetic material 2 located at the center of the magnetic field with respect to the central axis of the wound coil 1 through the induction coil 1, The rise time and the heat generation of the ferromagnet due to variables such as the induced current and the thickness of the coil, the diameter of the wound coil, the length (height) of the coil, the intensity of the magnetic field, alternating frequency, The temperature is determined,

By adjusting the optimum parameters as described above, the ferromagnetic body can be set to be in the optimum heat generation state and adjusted to generate (emit) high heat. Most of the current induction induction heating methods are manufactured / produced / sold through optimization of the above-mentioned method. However, in the above method, the alternating magnetic field in the heating of the ferromagnetic body (heating element) A large amount of current should be applied to the induction coil in order to reach the alternating magnetic field at the center depth of the heating coil.

The conventional induction induction heating method requires a lot of energy and time for the heat source generated inside the ferromagnetic body (heating element) to reach the surface (conducted) and release it as natural convection or radiant heat. In addition, the heat transfer method such as conduction / convection / radiation can be used by recovering the generated / emitted heat source. In the induction induction method, since the induction coil surrounds the ferromagnetic material as the heating element, It is difficult structure.

Also, in the induction induction heating method, the natural convection method is mostly used, which requires a long time to raise the temperature to the target temperature.

In addition, due to the structure of the ferromagnetic material (heating element), in the recovery of radiant heat emitted in the form of an electromagnetic wave or a photon through a structural change of an atom or a molecular state possessed by the material, it depends on the surface area of the ferromagnetic body (heating element).

This is because the energy required to effectively raise the temperature of the object by 1 ° C is the static specific heat (the energy required to increase the temperature of an object of a unit mass by 1 ° C from a certain volume) and the specific heat of static pressure (the temperature of an object of a unit mass at a constant pressure is 1 The energy efficiency is determined by the energy required to increase the temperature (in degrees Celsius). The conventional method of conduction / convection / radiation, which is the conventional method, has low efficiency.

In addition, the conventional induction induction heating apparatus requires a large volume and heavy weight. In order to convert cold water into warm water at 40 ° C, electric power of about 2.5 kW to 6 kW is consumed, There was a problem to be consumed.

Korean Patent Publication No. 10-2016-0131521 Korean Utility Model Publication No. 20-2017-0000711 Korean Utility Model Registration No. 20-0190688 Korean Utility Model Registration No. 20-0226266

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and it is an object of the present invention to maximize a heat generating surface area by changing the shape and structure of a ferromagnetic body, And the friction generated by friction between the fluid and the heat generated by the ferromagnet (heating element) can be quickly and quickly transferred to the fluid, so that the required fluid temperature can be raised very quickly and quickly, Which is capable of ensuring a useful heat source for the induction heating and heat transfer system.

According to an aspect of the present invention, there is provided an induction induction heating and heat transfer system including a coil wound for induction heating, a bobbin provided inside the coil for fixing a coil wound on the coil, An inlet nozzle installed in the outer periphery of the fixed heat generating portion and passing through the upper and lower portions to supply fluid into the fixed heat generating portion; And a rotary heat transfer unit for spirally rotating the fluid supplied through the nozzle so that the heat source generated in the fixed heating unit can be transferred to the fluid.

The fixed heat generating part is installed on the inside of the bobbin so as to be stacked up and down. The outer heating part has a first inlet for introducing the fluid supplied from the inlet nozzle, and a discharge port for discharging the fluid. And a non-magnetic permanent gap plate provided to maintain a predetermined gap between the heat generating plate and a second inlet to communicate with the first inlet through the outer frame.

The heat generating disc may be formed of a non-magnetic material so as to uniformly penetrate the alternating magnetic field, and alternating magnetic field holes may be filled with the ferromagnetic material.

The alternating magnetic field holes filled with the ferromagnetic material may be provided with a nonmagnetic disk that maintains flatness such as the surface of the heat generating disk so as to prevent turbulence and to maintain smooth fluid flow.

In the heat generating disk, the ferromagnetic bodies may be uniformly spaced apart from each other in the non-magnetic disk so that the alternating magnetic field is uniformly distributed on the heat generating disk.

The rotary heat transfer unit includes a rotary disk having a fluid discharge port formed at a predetermined interval in the fixed heat generating unit so as to rotate the fluid and discharge the fluid to the outside in the vicinity of the center of the rotary disk, And a center axis passing through the center of the rotation disc and the center of the rotation gap disc to rotate the rotation disc.

Upper and lower covers may be installed on upper and lower sides of the bobbin to prevent leakage of fluid flowing through the inlet nozzle and flowing out to the outlet.

As described above, according to the induction induction heating and heat transfer system of the present invention, compared with the heat generation process of the conventional inverter type heat generating device, the temperature rise time to the target temperature due to the rapid penetration of the magnetic field into the ferromagnetic material And the additional heat generation (generation) of the frictional heat of the fluid due to the high speed rotation of the rotating disk due to the short heat transfer and the heat transfer process of the fluid fluid not existing in the existing system, It is possible to manufacture a product with a reduced volume and a light weight of the product, and it is easy to manufacture in the manufacturing process of the product, and the manufacturing cost is reduced.

In addition, the present invention provides many advantages to the commercialization and provides safety to the user because the heating unit is separated from the power source and the heat source, and the temperature of the cold water is rapidly and rapidly increased with less power compared with the conventional method, It is possible to obtain hot water or steam at a desired temperature immediately without waiting. This is because the use of the present non-contact instantaneous electric water heater is removed from a limited market such as a shower, a toilet, and a kitchen, It is possible to expand indefinitely for industrial use, agricultural use and the like. Especially, it is effective to reduce the production cost of crops when it is extended for agricultural use (reduction of heating cost in growing green house).

In addition, the present invention has the effect of reducing the volume of existing hot water storage type products, reducing the number of parts, reducing the production cost, reducing the transportation cost, and reducing the installation cost, The installation improves the utilization of the space, the convenience of easy carrying, the reduction of the introduction cost, and the reduction of the operation cost.

In addition, the present invention can be applied to the transportation of vehicles using purely electric energy without using fossil fuels in the future (future), and in the heating of such future transportation means, it consumes small volume, light weight, The need for a heating device will be greatly increased, and when applied to a moving means such as an electric vehicle, it is effective to increase the travel distance of the electric vehicle and increase the competitiveness of the electric vehicle.

1 is a perspective view showing an induction induction coil and a bobbin of an induction induction heating and heat transfer system according to the present invention.
2A is a perspective view illustrating a stacked fixed heating unit of an induction induction heating and heat transfer system according to the present invention.
2B is an exploded perspective view illustrating a fixed heating unit of the induction induction heating and heat transfer system according to the present invention.
FIG. 3A is an exploded perspective view showing a stacked rotary heat transfer unit of the induction induction heating and heat transfer system according to the present invention. FIG.
3B is a perspective view illustrating a rotary heat transfer unit in which a rotary disk of the induction induction heating and heat transfer system according to the present invention is stacked.
FIG. 4A is a partial perspective view illustrating a state where the fixed heating unit, the rotary heat transfer unit, and the inlet nozzle of the induction induction heating and heat transfer system according to the present invention are cut.
FIG. 4B is a partial perspective view illustrating a fixed heat generating unit, a rotary heat transfer unit, and an inlet nozzle of the induction induction heating and heat transfer system according to the present invention.
FIG. 5A is an exploded perspective view showing a state in which a coil and a bobbin are removed from an induction induction heating and heat transfer system according to the present invention. FIG.
5B is a perspective view illustrating a cut-off state of the induction induction heating and heat transfer system according to the present invention.
FIGS. 6A and 6B are exploded perspective views of the induction induction heat generating and heat cutting system according to the present invention in the cut state. FIG.
7 is an assembled perspective view illustrating a cut-off state of the induction induction heating and heat transfer system according to the present invention.
8 is a sectional view showing an operation state of the induction induction heating and heat transfer system according to the present invention.
9 is an overall perspective view of the induction induced heat and heat transfer system according to the present invention.
10A and 10B are perspective views illustrating an example of a heat generating disk of the induction induction heating and heat transfer system according to the present invention.
11 is a configuration diagram for use of the apparatus of the induction induction heating and heat transfer system according to the present invention.
12 is a front view showing a conventional induction induction heating device.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

In the drawings, embodiments of the present invention are not limited to the specific forms shown and are exaggerated for clarity. Although specific terms are used herein, they are used for the purpose of describing the invention and are not used to limit the scope of the invention as defined in the claims or the meaning of the claims.

The expression " and / or " is used herein to mean including at least one of the elements listed before and after. Also, the expression " coupled / connected " is used to mean either directly connected to another component or indirectly connected through another component. The singular forms herein include plural forms unless the context clearly dictates otherwise. Also, as used herein, "comprising" or "comprising" means to refer to the presence or addition of one or more other components, steps, operations and elements.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view showing an induction induction coil and a bobbin of an induction induction heat generating and heat transfer system according to the present invention, FIG. 2 (a) is a perspective view showing a stacked fixed heat generating unit of an induction induction heat generating and heat transfer system according to the present invention, FIG. 2B is an exploded perspective view illustrating a fixed heating unit of the induction induction heating and heat transfer system according to the present invention, FIG. 3A is an exploded perspective view illustrating a stacked rotary heat transfer unit of the induction induction heating and heat transfer system according to the present invention, FIG. 3B is a perspective view illustrating a rotary heat transfer unit in which a rotating disk of the induction induction heat generating and heat transfer system according to the present invention is stacked. FIG. 4A is a perspective view of the induction induction heat generating and heat transfer system according to the present invention, FIG. 4B is a partially-assembled perspective view showing a cut-off state of the delivery portion and the inlet nozzle, and FIG. 4B is a perspective view of the induction- FIG. 5A is an exploded perspective view showing a cutting state in which a coil and a bobbin are removed from the induction induction heating and heat transfer system according to the present invention, and FIG. 5A is an exploded perspective view 6a and 6b are exploded perspective views of the induction induced heat generation and heat transfer system according to the present invention in a cut state, and FIGS. 6a and 6b are exploded perspective views of the induction induction heat generation and heat transfer system according to the present invention, FIG. 7 is a perspective view illustrating a cut-off state of the induction induction heat generating and heat transferring system according to the present invention, FIG. 8 is a sectional view showing an operating state of the induction inducing heat generating and heat transferring system according to the present invention, 10a and 10b are perspective views of induction induced heat generation and heat transfer according to the present invention, A perspective view showing an example of the heat generating original plate of the system, Figure 11 is a schematic exemplary diagram for using apparatus of the induction heating and induction heat transfer system of the present invention.

1 to 10, an induction induction heating and heat transfer system according to the present invention includes a coil 101, a bobbin 102, a stationary heat generating part 200, an inlet nozzle 206, A rotary heat transfer unit 300, an upper cover 601, and a lower cover 602.

1, the coil 101 is wound on the outside of the bobbin 102 to generate an alternating magnetic field, and terminals (not shown) for supplying electric power are provided on both ends of the coil 101. As shown in FIG.

In addition, the coil 101 may be protected from electric shock by impregnating or coating with an insulating material such as an insulating coating or epoxy for insulation.

A ZVS (Zero Volt Switching) switching control method may be used to supply power to the coil 101 to apply an alternating magnetic field.

The bobbin 102 is installed inside the coil 101 to wind the coil 101 and fix the fixed heat generating part 200 and the rotary heat transmitting part 300 described below.

As shown in FIGS. 2 and 7, the fixed heating unit 200 is installed in the bobbin 102 so as to be stacked up and down for heat generation.

The fixed heating unit 200 includes a heating plate 201 of a ferromagnetic material stacked on top and bottom and a fixed interval circular plate 202 of a nonmagnetic material installed to maintain a predetermined distance between the heating plate 201 ).

That is, the fixed heating unit 200 includes at least one fixed interval disc 202 and a heat generating disc 201 stacked alternately one on top of the heat generating disc 201 of a ferromagnetic material, (201) are stacked.

2, the heat generating disc 201 has a first inlet 203 for introducing a fluid supplied from the inlet nozzle 206 to an outer portion thereof, and an outlet 205 for discharging the fluid is formed at the center Respectively.

A plurality of first fixing holes 204 are formed in the heat generating disk 201 so that the fixing gap disk 202 and the upper and lower covers 601 and 602 can be fixed by fastening members such as bolts Respectively.

Also, as shown in FIG. 10A, a plurality of alternating magnetic field holes 201a are formed in the heat generating disk 201 so as to uniformly penetrate the alternating magnetic field.

In order to prevent the turbulence and maintain smooth flow of the fluid, a nonmagnetic body disk 207 made of a nonmagnetic material such as aluminum or copper which maintains flatness such as the surface of the heat generating disk 201 is provided in the alternating magnetic field hole 201a Respectively.

The alternating magnetic field holes 201a are formed in the center of the lowest heat generating plate 201 where the stacking of the heat generating plates 201 starts and the center of the upper heat generating plate 201 stacked And the center of gravity is positioned at a certain helical angle with respect to the central axis of the center of gravity.

As shown in FIG. 10B, the ferromagnetic material body 208 is provided in the non-magnetic material disk 207 so that the alternating magnetic field is uniformly distributed in the heat generating disk 201 and penetrated into the heat generating disk 201.

In this case, the ferromagnetic masses 208 are spaced apart at regular intervals in the form of chips or pellets.

The fixed gap circular plate 202 is formed with a second inlet 203a communicating with the first inlet 203 at an outer portion thereof and communicated with the first fixing hole 204, And a plurality of second fixing holes 204a for fixing the lower covers 601 and 602 are formed.

The inlet nozzle 206 is installed on the outer periphery of the fixed heat generating part 200 so as to pass through the upper and lower parts and supply the fluid into the fixed heat generating part 200.

That is, the inlet nozzle 206 is fixed to the upper cover 601 through the first inlet 203 of the heat generating disk 201 and the second inlet 203a of the fixed gap disk 202, The fluid can be supplied into the fixed heat generating portion 200 through the heat exchanger 206.

3, the rotary heat transfer unit 300 is installed inside the stationary heat generating unit 200 and spirally rotates the fluid supplied through the inlet nozzle 206 to generate heat in the fixed heat generating unit 200 So that it can be transferred to the fluid.

The rotary heat transfer unit 300 includes a rotary disk 301, a rotary disk 302, and a central shaft 304.

The rotary discs 301 are stacked at predetermined intervals in the fixed heat generating unit 200 and can be rotated by the pressure of the fluid supplied through the inlet nozzle 206.

Also, a fluid outlet 303 is formed in the rotary disk 301 so that the fluid is discharged to the outside in the vicinity of the center.

The rotation gap discs 302 may be alternately disposed between the rotation discs 301 to maintain a gap between the rotation discs 301 stacked.

The center axis 304 is provided to pass through the center of the rotation disc 301 and the rotation disc disc 302 to rotate the rotation disc 301.

Although not shown, magnetic bearings using mechanical bearings or magnets may be optionally provided at both ends of the center shaft 304 in order to support the rotary heat transfer portion 300.

As the center shaft 304 is rotated, the rotary disk 301 is rotated and the fluid supplied through the inlet nozzle 206 is rotated to hit the heat generation disk 201, and the fluid is supplied to the heat source of the fixed heat generator 200 So that the fluid is heated.

The upper cover 601 is installed on the upper portion of the bobbin 102 to prevent leakage of fluid flowing through the inlet nozzle 206.

The lower cover 602 is installed at a lower portion of the bobbin 102 to prevent leakage of fluid flowing through the inlet nozzle 206.

The upper cover 601 and the lower cover 602 are formed with an upper inlet 603 and a lower inlet 603a for introducing fluid from the outside and connecting the inlet nozzle 206, respectively.

An upper discharge port 605 and a lower discharge port 605a are formed at the center of the upper cover 601 and the lower cover 602 so as to discharge the hot water or steam fluid, .

The center shaft 304 is connected to the center of the upper discharge port 605 and the lower discharge port 605a to form a bearing insertion hole h for fixing the rotary heat transfer part 300.

As shown in FIG. 7, the heat insulating and shielding shield 209 is provided between the bobbin 102 and the coil 101 to minimize heat loss and noise.

11, a solenoid valve V for safe operation and a temperature sensor S-1 for sensing the temperature of the fluid received are attached to the rotary heat transfer part 300. [

In addition, a pressure regulating pump P and a flow rate sensor S-2 are installed in the rotary heat transfer part 300 to adjust the rotational speed of the fluid

In this case, the temperature sensor S-1 is transferred to the MCU through the ADC conversion circuit, and the MCU determines whether to increase or decrease the temperature of the fluid by calculating the outgoing temperature-incoming temperature =? T.

Further, it is possible to control the flow rate / flow rate of the fluid through the flow rate sensor S-2 to control the flow rate / flow rate / prevention of the overheating rise, etc., And the alternating frequency, or by controlling the pressure of the pressure regulating pump (P) to control the desired target temperature.

As shown in FIG. 8, the overheat prevention sensor S-3 is installed on the heat generation disc 201 so as to prevent the overheat of the ferromagnetic material (heat generating element).

In order to sense the resistance change of the overheat prevention sensor (S-3), the signal is transmitted to the MCU through the ADC conversion circuit and the GPIO of the MCU is controlled through the gate terminal of the MOSFET, IGBT, The pump (P) is controlled or the current of the induction coil is controlled.

In this way, the voltage, current, and power application time of the coil 101 are controlled to obtain hot water of a desired temperature.

As described above, the fluid flows into the fixed heat generating part 200 through the inlet nozzle 206, and the inflow fluid is rotated by the spiral between the heat generating disks 201 stacked by the inflow pressure, The heat generated from the heat generating disk 201 is transferred to the fluid for spiral rotation.

At this time, the fluid in contact with the heat generation disc 201 is expanded in volume, and the expanded molecules are in collision contact with the rotary disc 301 of the rotary heat transfer unit 300 installed between the heat generation discs 201 by the expansion force, And the rotating friction force of the fluid is transmitted to the rotary disk 301 of the rotary heat transfer unit 300 so that the rotary heat transfer unit 300 rotates at a high speed.

The heat source generated by the heat generation disc 201 is rapidly and rapidly transferred to the fluid by the rotary disc 301 of the rotary heat transfer unit 300 rotating at a high speed. Thereby preventing melt down phenomenon.

Through this process, the fluid for spiral rotation is discharged to the outside through the outlet port 205, the fluid outlet port 303, and the upper and lower outlet ports 605 and 605a near the central axis 304.

In addition, the rotary heat transfer unit 300 can rotate at a high speed of 10,000 rpm to 100,000 rpm according to the inflow pressure of the fluid and the heat of the alternating magnetic field.

As described above, the present invention is not limited to the above-described specific preferred embodiments, and any person skilled in the art can make various modifications without departing from the gist of the present invention. It is to be understood that such changes and modifications are intended to fall within the scope of the appended claims.

101: coil 102: bobbin
200: Fixed heating unit 201: Heat generating plate
201a: alternating magnetic field hole 202: fixed interval disk
203: first inlet 203a: second inlet
204: first fixing hole 204a: second fixing hole
205: Outlet 206: Inlet nozzle
207: non-magnetic body disk 208: ferromagnetic body mass
209: Insulation and sound shielding material 300: Rotary heat transfer part
301: rotating disk 302: rotating gap disk
303: fluid outlet 304: center axis
601: upper cover 602: lower cover
603: upper intake port 603a: lower intake port
605: upper outlet 605a: lower outlet
h: Bearing insertion hole V: Solenoid valve
P: Pressure regulating pump S-1: Temperature sensor
S-2: Flow sensor S-3: Overheat prevention sensor

Claims (7)

A coil wound for induction heating;
A bobbin provided inside the coil for fixing the coil wound around the bobbin;
At least one fixed heat generating part for generating heat inside the bobbin;
A water inlet nozzle installed above and below the fixed heat generating portion to supply fluid into the fixed heat generating portion; And
A rotary heat transfer unit installed in the fixed heat generating unit for spirally rotating the fluid supplied through the inlet nozzle to transfer the heat generated by the fixed heat generating unit to the fluid;
/ RTI >
Wherein the fixed heat-
A heating base plate of a ferromagnetic body (heating body) which is installed in the bobbin so as to be stacked on top and bottom and has a first inlet for introducing a fluid supplied from the inlet nozzle into the outer frame and an outlet for discharging fluid at the center; And
A fixed interval circular plate provided to maintain a predetermined interval between the heat generation discs and having a second inlet port communicating with the first inlet port in an outer frame portion;
/ RTI >
The heat generating disk is made of a non-magnetic material so as to uniformly penetrate the alternating magnetic field, and the alternating magnetic field holes are filled with the ferromagnetic material,
The alternating magnetic field holes filled with the ferromagnetic material are provided with a nonmagnetic disk that maintains flatness such as the surface of the heat generating disk so as to prevent turbulence and to maintain smooth fluid flow,
The rotary heat transfer unit includes:
A rotating circular plate disposed in the fixed heat generating portion at predetermined intervals to rotate the fluid and having a fluid discharge port for discharging the fluid to the outside in the vicinity of the center;
A rotation gap disc provided between the rotation discs to maintain a gap between the rotation discs; And
A center axis passing through the center of the rotation disc and the rotation disc, and capable of rotating the rotation disc;
An induction induction heating and heat transfer system. delete delete delete The method according to claim 1,
Wherein an induction heating heat and heat transfer system is provided in the heat generating disk so that the alternating magnetic field is evenly distributed on the heat generating disk and penetrated into the non-magnetic body disk so that the ferromagnetic bodies are evenly spaced. delete The method according to claim 1,
Wherein an upper cover and a lower cover are installed on upper and lower sides of the bobbin to prevent leakage of fluid flowing through the inlet nozzle of the system and flowing out to the outlet.

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