Concentration measuring device for sewage sludge

Abstract

The utility model discloses a sewage sludge concentration measuring device, and relates to the technical field of sewage sludge treatment. The sewage sludge concentration measuring device comprises a shell, a light source emitting assembly and a scattered light receiving assembly, quartz glass is installed at one end of the shell, and the light source emitting assembly and the scattered light receiving assembly are both arranged in the shell. The light source emitting assembly comprises two LED light sources, a reference light detector and a beam splitter, and the two LED light sources with different wavelengths are arranged right opposite to the quartz glass and emit light alternately; the reference light detector is arranged on one side of the LED light source, and the beam splitter and the emergent optical axis of the LED light source are obliquely arranged at a first preset angle, so that one part of light emitted by the LED light source irradiates the surface of the quartz glass, and the other part of the light is reflected to the reference light detector. The receiving optical axis of the scattered light receiving assembly and the emergent optical axis of the LED light source are arranged at a second preset angle, and a light receiving detector of the scattered light receiving assembly is used for monitoring the intensity change of scattered light.

Description

TECHNICAL FIELD

[0001] The utility model relates to sewage sludge treatment technical field especially, relates to a concentration measuring device of sewage sludge. BACKGROUND

[0002] In the treatment process of sewage sludge, the size of activated sludge concentration is related to the number of microorganisms or the ability of oxidizing organic matter, by measuring the concentration of sewage sludge, the treatment effect of sewage sludge is judged. At present, the scattering light method is mainly used for measurement, by irradiating the light emitted by the light source into the sewage sludge, the scattered light generated by the particulate matter in the sewage sludge is used to measure the concentration of sludge. Among them, the intensity of scattered light is related to the concentration of particulate matter and the scattering coefficient of particulate matter, the higher the sludge concentration, the stronger the scattered light; the deeper the sludge color, the smaller the scattering coefficient; for the sludge with the same concentration, the deeper the sludge color, the smaller the intensity of scattered light.

[0003] The existing concentration measuring device of sewage sludge uses single-wavelength light source, and the concentration of sewage sludge is calculated according to the scattering intensity of light of light source, which cannot eliminate the concentration measurement error caused by the color change of sewage sludge. INVENTION CONTENTS

[0004] The utility model discloses a concentration measuring device of sewage sludge, which can correct the measurement error caused by the color change of sludge and improve the accuracy of detecting the concentration of sewage sludge.

[0005] To achieve this purpose, the utility model adopts the following technical scheme:

[0006] The concentration measuring device of sewage sludge comprises:

[0007] The shell is provided with a quartz glass at one end;

[0008] The light source exit assembly is arranged in the shell and comprises an LED light source, a reference light detector and a light splitting sheet. The LED light source is provided with two light sources, and the wavelengths of the light emitted by the two light sources are different. The two LED light sources are arranged opposite to the quartz glass and emit light alternately. The reference light detector is arranged on one side of the LED light source. The light splitting sheet is arranged at a first preset angle with the exit optical axis of the LED light source. The light splitting sheet is used to irradiate part of the light emitted by the LED light source to the surface of the quartz glass and reflect the other part of the light to the reference light detector. The reference light detector is used to monitor the intensity change of the LED light source.

[0009] The scattering light receiving assembly is arranged in the shell, a receiving light axis of the scattering light receiving assembly is arranged at a second preset angle with an outgoing light axis of the LED light source, and the scattering light receiving assembly is used for receiving scattered light of the sewage sludge after light emitted by the LED light source enters the sewage sludge through the quartz glass; the scattering light receiving assembly comprises a light receiving detector, and the light receiving detector is used for monitoring intensity change of the scattered light.

[0010] As an optional solution of the sewage sludge concentration measuring device, the light source outgoing assembly further comprises a first convex lens, the first convex lens is located between the LED light source and the reference light detector, and is used for converging light emitted by the LED light source.

[0011] As an optional solution of the sewage sludge concentration measuring device, the light source outgoing assembly further comprises an outgoing diaphragm, and the outgoing diaphragm is arranged between the light splitting sheet and the quartz glass.

[0012] As an optional solution of the sewage sludge concentration measuring device, the scattering light receiving assembly further comprises a second convex lens, the second convex lens is located between the quartz glass and the light receiving detector, and is used for converging the scattered light of the sewage sludge to the light receiving detector.

[0013] As an optional solution of the sewage sludge concentration measuring device, the scattering light receiving assembly further comprises a receiving diaphragm, and the receiving diaphragm is arranged between the quartz glass and the second convex lens.

[0014] As an optional solution of the sewage sludge concentration measuring device, the first preset angle is 45°, and the second preset angle is 45° or 135°.

[0015] As an optional solution of the sewage sludge concentration measuring device, the sewage sludge concentration measuring device further comprises a photoelectric signal processing circuit board, the photoelectric signal processing circuit board is arranged at an end of the shell away from the quartz glass, and the LED light source, the reference light detector and the light receiving detector are electrically connected with the photoelectric signal processing circuit board.

[0016] As an optional scheme of the concentration measuring device of the sewage sludge, the shell comprises an outer shell, a measuring head and a base, one end of the outer shell is provided with an opening, the measuring head and the base are arranged in the outer shell, the photoelectric signal processing circuit board is mounted on the measuring head, the light source exit assembly and the scattered light receiving assembly are electrically connected with the photoelectric signal processing circuit board, the measuring head divides the outer shell into a first accommodating cavity and a second accommodating cavity, the light source exit assembly and the scattered light receiving assembly are arranged in the first accommodating cavity, the base is arranged in the second accommodating cavity, and an external connector is arranged at one end of the base away from the measuring head.

[0017] As an optional scheme of the concentration measuring device of the sewage sludge, the quartz glass is connected to the opening through a gland sealing.

[0018] As an optional scheme of the concentration measuring device of the sewage sludge, the shell is made of stainless steel.

[0019] And / or, the external connector is a waterproof connector.

[0020] The beneficial effects of the utility model are as follows:

[0021] The concentration measuring device of the sewage sludge comprises a shell, a light source exit assembly and a scattered light receiving assembly, a quartz glass is mounted at one end of the shell, the light source exit assembly and the scattered light receiving assembly are arranged in the shell, two LED light sources with different wavelengths of the light source exit assembly are arranged opposite to the quartz glass, a reference light detector is arranged on one side of the LED light source, and a part of light emitted by the LED light source is irradiated to the surface of the quartz glass through a light splitting piece arranged at a first preset angle with the exit optical axis of the LED light source, and the other part is reflected to the reference light detector. When detecting, the quartz glass enters the liquid surface of the sewage sludge to a set depth, the light emitted by the LED light source enters the sewage sludge through the quartz glass, and the scattered light of the sewage sludge is received by the scattered light receiving assembly. Since the light with different wavelengths has different reflectivity, the longer the wavelength is, the smaller the reflection ability is; the shorter the wavelength is, the stronger the reflection ability is. After the color of the sludge changes, the scattering intensity of the sludge changes after the light with different wavelengths irradiates the sludge, and the ratio of the scattering intensity changes after the light with different wavelengths irradiates the sludge. The concentration measurement result of the sludge is corrected according to the increase and decrease of the ratio of the scattering intensity of the sludge after the light with different wavelengths irradiates the sludge, so that a more accurate concentration value of the sewage sludge is obtained, the correction of the measurement error caused by the color change of the sludge is realized, and the accuracy of the concentration detection of the sewage sludge is improved. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1Is the structure schematic view of the concentration measuring device of sewage sludge provided by the embodiment of the utility model.

[0023] Figure 2 Is the electric control system principle view of the concentration measuring device of sewage sludge provided by the embodiment of the utility model.

[0024] In the drawing,

[0025] 1, shell;11, outer shell;111, gland;12, measuring head;13, base;

[0026] 2, light source exit assembly;21, LED light source;22, reference light detector;23, light splitting sheet;24, first convex lens;25, exit diaphragm;

[0027] 3, scattered light receiving assembly;31, light receiving detector;32, second convex lens;33, receiving diaphragm;

[0028] 4, photoelectric signal processing circuit board;41, constant current drive circuit board;42, photoelectric signal filter amplifier circuit;43, analog-digital conversion circuit;44, communication circuit;45, single-chip microcomputer circuit;

[0029] 5, quartz glass;

[0030] 6, external connector. Specific embodiments

[0031] In order to make the technical problems solved by the utility model, the technical scheme adopted and the technical effects reached more clear, the technical scheme of the utility model will be further explained by combining with the drawings and through specific embodiments.

[0032] In the description of the utility model, unless another explicit provision and limitation, the terms "connected", "connected", "fixed" should be broad sense understanding, for example, can be fixed connection, can also be detachable connection, or integral;Can be mechanical connection, can also be electrical connection;Can be directly connected, can also be indirectly connected through intermediate medium, can be the communication of two elements or the interaction of two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0033] As Figure 1As shown, the embodiment provides a concentration measuring device for sewage sludge, which comprises a shell 1, a light source emitting assembly 2 and a scattered light receiving assembly 3. The shell 1 is provided with a quartz glass 5 at one end. The light source emitting assembly 2 and the scattered light receiving assembly 3 are arranged in the shell 1, so that the light source emitting assembly 2 and the scattered light receiving assembly 3 are both in the sealed shell 1. When the concentration of the sewage sludge is tested, the concentration measuring device for sewage sludge is inserted into the sewage sludge liquid surface to a set depth. The light emitted by the light source emitting assembly 2 enters the sewage sludge through the quartz glass 5. The scattered light of the sewage sludge is received by the scattered light receiving assembly 3. According to the intensity of the scattered light of the sewage sludge received by the scattered light receiving assembly 3, the concentration of the sewage sludge is calculated.

[0034] The normal activated sludge is dark brown in color. During the treatment of the sewage sludge, the color of the activated sludge changes with the health status of the sewage sludge and the effect of the process operation, and may become dark or gray-black. Especially when the microbial strain called "red bacteria" is used for the treatment of the sewage sludge, the color change of the sludge is more obvious. For the sewage sludge with the same concentration, the deeper the color of the sewage sludge, the smaller the scattering coefficient, and the intensity of the scattered light of the sewage sludge received by the scattered light receiving assembly 3 is also reduced. Then the concentration of the sewage sludge calculated according to the intensity of the scattered light of the sewage sludge received by the scattered light receiving assembly 3 is reduced, which affects the accuracy of the concentration measurement value of the sewage sludge.

[0035] In order to solve the error caused by the color change of the sludge to the concentration measurement value of the sewage sludge, the concentration measuring device for sewage sludge provided by the embodiment comprises a light source emitting assembly 2, which comprises LED light sources 21, a reference light detector 22 and a light splitting sheet 23. The two LED light sources 21 are arranged opposite to the quartz glass 5 and emit light alternately. The reference light detector 22 is arranged on one side of the LED light source 21. The light splitting sheet 23 is arranged at a first preset angle with the exit optical axis of the LED light source 21, so as to irradiate part of the light emitted by the LED light source 21 to the surface of the quartz glass 5 and reflect the other part to the reference light detector 22. The reference light detector 22 is used to monitor the intensity change of the LED light source 21, so as to ensure that the intensity of the light emitted by the LED light source 21 is constant. The receiving optical axis of the scattered light receiving assembly 3 is arranged at a second preset angle with the exit optical axis of the LED light source 21. The scattered light receiving assembly 3 is used to receive the scattered light of the sewage sludge after the light emitted by the LED light source 21 enters the sewage sludge through the quartz glass 5. The scattered light receiving assembly 3 comprises a light receiving detector 31, which is used to monitor the intensity change of the reflected light.

[0036] Different wavelengths of light have different reflectivity, the longer the wavelength, the smaller the reflection ability; the shorter the wavelength, the stronger the reflection ability. After the color of the sludge changes, different wavelengths of light irradiate the sludge, the scattering intensity of the sludge changes, and the ratio of the scattering intensity of the sludge irradiated by different wavelengths of light changes. The sludge concentration measurement result is corrected according to the increase and decrease of the ratio of the scattering intensity of the sludge irradiated by different wavelengths of light, so as to obtain more accurate concentration value of the sewage sludge, correct the measurement error caused by the color change of the sludge, and improve the accuracy of the detection of the concentration of the sewage sludge.

[0037] Suppose that the two different wavelengths of LED light sources 21 are red LED light sources and blue LED light sources respectively, and it is known that when the sewage sludge is normally dark brown, the ratio of the scattering intensity of the sludge irradiated by the two different wavelengths of light is S = I 红 / I 蓝 When the sewage sludge with the concentration to be detected is detected by using the above sewage sludge concentration measuring device, the red LED light source works, and the scattering light intensity received by the light receiving detector 31 is I 红 ˊ; the blue LED light source works, and the second scattering light intensity received by the light receiving detector 31 is I 蓝 ˊ, at this time Sˊ = I 红 ˊ / I 蓝 ˊ, since the wavelength of red light is greater than that of blue light, when the red LED light source works, less light is reflected to the quartz glass 5; when the blue LED light source works, more light is reflected to the quartz glass 5; when the color of the sludge becomes darker, the intensity of the scattering light becomes smaller, and the change of the intensity of the red light scattering light is greater than that of the blue light scattering light.

[0038] When the concentration of the sewage sludge is the same, after the color of the sludge becomes darker, the intensity of the blue light changes less than that of the red light, so Sˊ increases compared with S, at this time the correction coefficient is determined to be greater than 1; otherwise, the correction coefficient is determined to be less than 1. Finally, the detection value of the concentration of the sewage sludge obtained by irradiating the sewage sludge with the red LED light source 21 is taken as the reference value, and the reference value is multiplied by the correction coefficient, so as to obtain the accurate concentration of the sewage sludge.

[0039] Of course, in other embodiments, the two different wavelengths of LED light sources 21 can also be divided into red LED light sources and green LED light sources.

[0040] Regarding the determination of the correction coefficient, those skilled in the art can formulate a correction coefficient table corresponding to the change amount of the ratio of the scattering intensity of the sludge irradiated by two different wavelengths of light according to experiments, and then obtain the corresponding correction coefficient according to the change amount of the ratio of the scattering intensity of the sludge irradiated by two different wavelengths of light obtained by detection.

[0041] The sewage sludge concentration measuring device also includes a photoelectric signal processing circuit board 4, which is arranged at one end of the shell 1 away from the quartz glass 5, and the LED light source 21, the reference light detector 22 and the light receiving detector 31 are all electrically connected to the photoelectric signal processing circuit board 4.

[0042] Specifically, if Figure 2 As shown, the photoelectric signal processing circuit board 4 includes a light source constant current driver circuit board 41, a photoelectric signal filtering and amplifying circuit 42, an analog-to-digital conversion circuit 43, a communication circuit 44, and a single-chip microcomputer circuit 45. Two LED light sources 21 of different wavelengths are mounted on the light source constant current driver circuit board 41. They are driven by the light source constant current driver circuit board 41 to emit light alternately in a pulsed manner. When one LED light source 21 is operating and emitting light, the other LED light source 21 is inactive and emitting light. The reference light detector 22 and the light receiving detector 31 are both electrically connected to the photoelectric signal filtering and amplifying circuit 42. Both the reference light detector 22 and the light receiving detector 31 simultaneously convert the reference light signal and the scattered light signal from the operating light source into electrical signals. The photoelectric signal filtering and amplifying circuit 42 filters and amplifies the reference photoelectric signal and the scattered photoelectric signal to remove circuit interference. The analog-to-digital conversion circuit 43 converts the reference photoelectric signal and the scattered photoelectric signal into digital signals, respectively. The communication circuit 44 communicates with external circuits using an S85 signal transmission method. The single-chip microcomputer circuit 45 controls the operation of the light source constant current driver circuit board 41, the photoelectric signal filtering and amplifying circuit 42, the analog-to-digital conversion circuit 43, and the communication circuit 44. The single chip circuit 45 processes the received reference photoelectric signals of the two LED light sources 21 with different wavelengths to eliminate the influence of the light source attenuation on the measurement result.

[0043] The specific structure and working principle of the optoelectronic signal processing circuit board 4 are not the focus of improvement in this embodiment and can be designed with reference to the existing technology, so they will not be described in detail here.

[0044] In one embodiment, the light emitting assembly 2 further includes a first convex lens 24, which is located between the LED light source 21 and the reference light detector 22 and is configured to converge the light emitted by the LED light source 21. The first convex lens 24 converges the light emitted by the LED light source 21 to a focal point of the first convex lens 24, which is located several millimeters below the contact plane between the quartz glass 5 and the sewage sludge.

[0045] Specifically, the first convex lens 24 is a first plano-convex lens, the emission surface of the LED light source 21 contacts one side of the plane of the first plano-convex lens, and the light emitted by the LED light source 21 is converged by the first plano-convex lens and then emitted.

[0046] Furthermore, the light source output assembly 2 further includes an output aperture 25, which is provided between the beam splitter 23 and the quartz glass 5. The output aperture 25 is used to limit the angle of the output light beam and reduce stray light.

[0047] In an embodiment, the first preset angle is 45°. A light splitting plate 23 is inserted in the light path of the LED light source 21, and the light splitting plate 23 is at an angle of 45° with respect to the light axis. Most of the light rays pass through the light splitting plate 23, enter the exit diaphragm 25, and then enter the sewage sludge through the quartz glass 5. A small part of the light rays is reflected by the light splitting plate 23 into the reference light detector 22 to monitor the intensity change of the LED light source 21. Specifically, the light splitting plate 23 is a flat glass plate.

[0048] In an embodiment, the second preset angle is 45° or 135°. When the LED light source 21 is incident in a direction perpendicular to the surface of the quartz glass 5 (i.e., perpendicular to the liquid surface of the sewage sludge), the propagation characteristics of the light scattered by the sewage sludge in a direction at an angle of 45° with respect to the light axis are optically analyzed. The receiving axis and the light axis are at an angle of 45° or 135°, and intersect at the focal point of the exit light. The scattering light receiving assembly 3 and the light source exit assembly 2 are arranged on the same side of the quartz glass 5. The scattering light receiving assembly 3 can be arranged on both sides of the light source exit assembly 2 to receive the scattered light of the sewage sludge. The intensity of the scattered light is detected by the light receiving detector 31.

[0049] In an embodiment, the scattering light receiving assembly 3 further comprises a second convex lens 32, which is located between the quartz glass 5 and the light receiving detector 31, and is used to converge the scattered light of the sewage sludge to the light receiving detector 31. The second convex lens 32 is a second plano-convex lens, and the plane of the second plano-convex lens is arranged to face the light receiving detector 31 to focus the scattered light to the light receiving detector 31.

[0050] Further, the scattering light receiving assembly 3 further comprises a receiving diaphragm 33, which is arranged between the quartz glass 5 and the second convex lens 32. The receiving diaphragm 33 prevents the reflected light of the quartz glass 5 from entering the receiving light path. The scattered light of the sewage sludge is received by the receiving diaphragm 33 and then converged to the light receiving detector 31 by the second convex lens 32, thereby ensuring the intensity of the scattered light received by the light receiving detector 31.

[0051] The shell 1 comprises an outer shell 11, a measuring head 12, and a base 13. One end of the outer shell 11 is provided with an opening, and the quartz glass 5 is arranged at the opening. The photoelectric signal processing circuit board 4 is mounted on the measuring head 12. The light source exit assembly 2 and the scattering light receiving assembly 3 are electrically connected to the photoelectric signal processing circuit board 4. The measuring head 12 divides the inner space of the outer shell 11 into a first accommodating cavity and a second accommodating cavity. The light source exit assembly 2 and the scattering light receiving assembly 3 are arranged in the first accommodating cavity, and the base 13 is arranged in the second accommodating cavity. The end of the base 13 away from the measuring head 12 is provided with an external connector 6. One end of the external connector 6 is electrically connected to the photoelectric signal processing circuit board 4, and the other end of the external connector 6 extends out of the outer shell 11 to be connected to an external power supply.

[0052] Specifically, the quartz glass 5 is sealingly connected to the opening by the gland 111, and the exit aperture 25 and the receiving aperture 33 are both in abutment with the quartz glass 5. The gland 111 is threadedly connected to the opening of the housing 11, and the quartz glass 5 is sealingly fixed in the central hole of the gland 111 by light-sensitive glue.

[0053] Further, the external connector 6 is a waterproof connector for connecting a 12V or 24V power supply and a 485 communication interface.

[0054] The housing 11 is made of high-strength and corrosion-resistant stainless steel material, and O-shaped sealing rings are arranged at the connection positions of the gland 111 and the waterproof connector with the housing 11, so that the light source exit assembly 2, the scattered light receiving assembly 3 and the photoelectric signal processing circuit board 4 are installed in a measuring space with a sealing performance of IP68.

[0055] The above is only the preferred embodiment of the present application, and for those skilled in the art, the specific implementation and application range can be changed according to the idea of the present application, and the content of the specification should not be understood as a limitation of the present application.

Claims

1. A device for measuring the concentration of sewage sludge, characterized by, The application relates to a concentration measuring device for sewage sludge, which comprises the following parts: a shell (1) provided with a quartz glass (5) at one end; a light source exit assembly (2) arranged in the shell (1) and comprising LED light sources (21), a reference light detector (22) and a light splitting sheet (23), wherein the LED light sources (21) are arranged in pairs and emit light rays with different wavelengths, the two LED light sources (21) are arranged opposite to the quartz glass (5) and emit light alternately, the reference light detector (22) is arranged on one side of the LED light source (21), and the light splitting sheet (23) is arranged at a first preset angle with the exit light axis of the LED light source (21) and is used for irradiating part of the light rays emitted by the LED light source (21) to the surface of the quartz glass (5) and reflecting the other part of the light rays to the reference light detector (22), and the reference light detector (22) is used for monitoring the intensity change of the LED light source (21); a scattered light receiving assembly (3) arranged in the shell (1), wherein the receiving light axis of the scattered light receiving assembly (3) is arranged at a second preset angle with the exit light axis of the LED light source (21), the scattered light receiving assembly (3) is used for receiving the scattered light rays of the sewage sludge after the light rays emitted by the LED light source (21) enter the sewage sludge through the quartz glass (5), and the scattered light receiving assembly (3) comprises a light receiving detector (31) used for monitoring the intensity change of the scattered light rays.

2. The apparatus for measuring concentration of sewage sludge according to claim 1, wherein The light source exit assembly (2) further comprises a first convex lens (24) arranged between the LED light source (21) and the reference light detector (22) and used for converging the light rays emitted by the LED light source (21).

3. The apparatus for measuring concentration of sewage sludge according to claim 2, characterized by The light source exit assembly (2) further comprises an exit diaphragm (25) arranged between the light splitting sheet (23) and the quartz glass (5).

4. The apparatus for measuring concentration of sewage sludge according to claim 1, wherein The scattered light receiving assembly (3) further comprises a second convex lens (32) arranged between the quartz glass (5) and the light receiving detector (31) and used for converging the scattered light rays of the sewage sludge to the light receiving detector (31).

5. The apparatus for measuring concentration of sewage sludge according to claim 4, wherein The scattered light receiving assembly (3) further comprises a receiving diaphragm (33) arranged between the quartz glass (5) and the second convex lens (32).

6. The apparatus for measuring concentration of sewage sludge according to claim 1, wherein The first preset angle is 45 degrees, and the second preset angle is 45 degrees or 135 degrees.

7. The apparatus for measuring concentration of sewage sludge according to any one of claims 1 to 6, characterized by The concentration measuring device for sewage sludge further comprises a photoelectric signal processing circuit board (4) arranged at the end of the shell (1) far from the quartz glass (5), and the LED light source (21), the reference light detector (22) and the light receiving detector (31) are electrically connected with the photoelectric signal processing circuit board (4).

8. The apparatus for measuring concentration of sewage sludge according to claim 7, wherein The shell (1) comprises an outer shell (11), a measuring head (12) and a base (13), one end of the outer shell (11) is provided with an opening, the measuring head (12) and the base (13) are arranged in the outer shell (11), the photoelectric signal processing circuit board (4) is installed on the measuring head (12), the light source emitting assembly (2) and the scattered light receiving assembly (3) are electrically connected with the photoelectric signal processing circuit board (4), the measuring head (12) divides the outer shell (11) into a first containing cavity and a second containing cavity, the light source emitting assembly (2) and the scattered light receiving assembly (3) are arranged in the first containing cavity, the base (13) is arranged in the second containing cavity, and one end of the base (13) away from the measuring head (12) is provided with an external connector (6); one end of the external connector (6) is electrically connected with the photoelectric signal processing circuit board (4), and the other end of the external connector (6) extends out of the outer shell (11) and is connected with an external power supply.

9. The apparatus for measuring concentration of sewage sludge according to claim 8, wherein The quartz glass (5) is sealingly connected to the opening through a gland (111).

10. The apparatus for measuring concentration of sewage sludge according to claim 8, wherein The outer shell (11) is made of stainless steel material; And / or, the external connector (6) is a waterproof connector.

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