CN115655414A - Non-contact liquid level detection device - Google Patents

Abstract

The invention relates to a non-contact liquid level detection device, which comprises an emitting module for emitting sensing rays, a receiving module for receiving the sensing rays, a first reflecting part and a second reflecting part, wherein the first reflecting part is arranged on the emitting module; the direction of the transmitting module is different from that of the receiving module, the transmitting module corresponds to the first reflecting part, and the receiving module corresponds to the second reflecting part; a crossing part is arranged between the transmitting module and the receiving module; the first reflection part and the second reflection part are oppositely matched with each other; when the liquid level is lower than the set liquid level height, the sensing ray is reflected by the first reflecting part, passes through the penetrating part, is reflected by the second reflecting part and reaches the receiving module, and an electric signal is arranged on the receiving module; when the liquid level reaches or is higher than the set liquid level height, the sensing rays are diffused in the liquid, and no electric signal exists on the receiving module. The non-contact liquid level detection device has the advantages of simple and reasonable structure, reliable performance, low manufacturing cost and high production efficiency.

Description

Non-contact liquid level detection device

Technical Field

The invention relates to a liquid level detector, in particular to a non-contact liquid level detection device.

Background

The existing non-contact water level sensor includes:

the infrared water level sensor is used for monitoring the water level based on the receiving condition of infrared rays; when no water body exists outside the reflecting surface, the infrared rays are reflected by the two mutually vertical reflecting surfaces and are finally received and generate corresponding electric signals; when a water body exists outside the reflecting surface, most or all infrared rays are scattered into the water body, and little or no infrared rays are received, so that an electric signal disappears, and the purpose of detecting the water level can be achieved; the water content detection system and the respirator with the same disclosed in the Chinese patent document CN209204376U concretely disclose that the optical liquid level sensor is electrically connected with the signal processing device, and the signal processing device is electrically connected with the controller; a light beam emitting tube and a light beam receiving tube are arranged in the optical liquid level sensor, the liquid level detection functional component comprises a first surface and a second surface which form a certain angle, the first surface and the second surface are made of light-transmitting materials, an included angle between the first surface and the second surface is 90 degrees, and the size of the first surface is the same as that of the second surface; also, as disclosed in chinese patent document CN110231839a, a device with infrared self-recognition liquid level control and ultra-low water level control specifically discloses that "the sensor hardware structure of the control device includes a sensor housing, a light-transmitting surface, an infrared transmitting tube, an infrared receiving tube and a baffle, the light-transmitting surface wraps the liquid level detection surface of the sensor housing, the infrared transmitting tube and the infrared receiving tube are respectively disposed on the left and right sides inside the sensor housing, the baffle is vertically disposed between the infrared transmitting tube and the infrared receiving tube", and "the liquid level detection surface is a 90-degree prism structure, and infrared rays transmitted by the infrared transmitting tube are reflected to the infrared receiving tube through the prism structure"; it can be seen that, the existing infrared water level sensor reflects infrared rays by relying on two mutually perpendicular reflecting surfaces, in practical application, the processing technology requirement of the reflecting surfaces is high (the two reflecting surfaces must be ensured to be mutually perpendicular), the orientation of the emitter is consistent with that of the receiver, the infrared rays can be smoothly received by the receiver after being reflected by the two mutually perpendicular reflecting surfaces, and the mounting positions of the visible emitter and the receiver need to be accurate (the position relation between the emitter and the reflecting surfaces must be accurate), so the production and assembly difficulty is high, the requirement is high, and the manufacturing cost is high due to the high-precision technology requirement.

The capacitance type water level sensor is used for detecting the water level based on the monitoring of the capacitance value, namely detecting the water level according to the change condition of the capacitance value; however, the capacitance is affected by many factors, including water quality (water quality affects conductivity), scale (scale affects capacitance), current, voltage, etc., so that the reliability and accuracy of capacitance water level detection are low, and complex and professional debugging is required to be performed in response to water quality in different areas during production, which results in high production difficulty and low production efficiency.

Therefore, there is a need for further improvement in view of the problems of the conventional non-contact water level sensor.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a non-contact liquid level detection device which is simple and reasonable in structure, reliable in performance, low in manufacturing cost and high in production efficiency.

The purpose of the invention is realized as follows:

a non-contact liquid level detection device comprises an emitting module used for emitting sensing rays, a receiving module used for receiving the sensing rays, a first reflecting part and a second reflecting part; the orientation of the transmitting module is different from the orientation of the receiving module, the transmitting module corresponds to the first reflecting part, and the receiving module corresponds to the second reflecting part; a penetrating part is arranged between the transmitting module and the receiving module; the first reflection part and the second reflection part are oppositely matched with each other; when the liquid level is lower than the set liquid level height, the sensing ray penetrates through the penetrating part after being reflected by the first reflecting part, and finally reaches the receiving module after being reflected by the second reflecting part, and an electric signal is arranged on the receiving module; when the liquid level reaches or is higher than the set liquid level height, the sensing rays are diffused in the liquid, and no electric signal exists on the receiving module.

As a specific solution, the transmitting module and the receiving module are respectively disposed between the first reflecting portion and the second reflecting portion; the orientation of the transmitting module is opposite to the orientation of the receiving module.

As another specific scheme, the non-contact liquid level detection device further includes a barrier for blocking the sensing rays, the crossing portion is disposed on the barrier, the transmitting module is disposed on one side surface of the barrier, and the receiving module is disposed on the other side surface of the barrier.

As another specific scheme, the penetrating part is a hollowed-out structure and/or a notch structure on the barrier body.

As another specific scheme, the non-contact liquid level detection device further includes a sleeve covered outside the barrier body, the barrier body divides an inner cavity of the sleeve into a first accommodating cavity and a second accommodating cavity, the transmitting module is disposed in the first accommodating cavity, the receiving module is disposed in the second accommodating cavity, the penetrating portion is disposed between the first accommodating cavity and the second accommodating cavity, and the sensing ray in the first accommodating cavity penetrates through the penetrating portion and enters the second accommodating cavity.

As a further specific aspect, the sleeve is made of a transparent material; the first reflecting part and the second reflecting part are respectively the inner side wall of the sleeve, and the first reflecting part and the second reflecting part are matched in parallel; when the liquid level reaches or is higher than the set liquid level height, the sensing ray penetrates through the first reflecting part and/or the second reflecting part to be diffused in the liquid; when the liquid level is lower than the set liquid level height, the sensing ray reaches the receiving module after being reflected by the first reflecting part and the second reflecting part.

As another specific scheme, the transmitting module and the receiving module are arranged up and down; the transmitting module, the receiving module, the first reflecting part and the second reflecting part are respectively arranged in a liquid storage cavity for loading liquid.

As still another specific embodiment, the sensing radiation is infrared radiation, laser radiation, or the like.

As another specific scheme, the transmitting module and the receiving module together form a group of detection assemblies, one or more groups of detection assemblies are arranged, and a blocking portion for blocking the sensing rays is arranged between two adjacent groups of detection assemblies.

As another specific solution, two or more of the transmitting modules are connected in parallel with each other, and two or more of the receiving modules are connected in parallel with each other; the receiving module is electrically connected with the corresponding indicator light.

The invention has the following beneficial effects:

in the device, the orientation of the transmitting module is different from that of the receiving module, the transmitting module corresponds to the first reflecting part, the receiving module corresponds to the second reflecting part, a penetrating part is arranged between the transmitting module and the receiving module, and the first reflecting part and the second reflecting part are matched relatively; when the liquid level is lower than the set liquid level height, the sensing ray is reflected by the first reflecting part, passes through the penetrating part, is reflected by the second reflecting part and reaches the receiving module, and an electric signal is arranged on the receiving module; when the liquid level reaches or is higher than the set liquid level height, the sensing rays are diffused in the liquid, and no electric signal exists on the receiving module. Compared with the prior art, the sensing ray in the application is reflected between two opposite reflecting parts (the two reflecting parts do not need to be perpendicular to each other), the directions of the transmitting module and the receiving module are not consistent (the directions of the transmitting module and the receiving module do not need to be consistent with each other), and the penetrating part between the transmitting module and the receiving module plays a role in limiting the penetration of part of the sensing ray; when the liquid level does not reach the set liquid level height, the sensing rays reflected for multiple times finally reach the receiving module, so that the receiving module generates corresponding electric signals, and the system judges that the liquid level does not reach the set liquid level height; when the liquid level reaches or exceeds the set liquid level height, the sensing rays are diffused into the liquid, the receiving module cannot generate corresponding electric signals due to the fact that the receiving module does not receive the sensing rays or the received sensing rays are insufficient, and the system judges that the liquid level reaches or exceeds the set liquid level height.

Specifically, the transmitting module and the receiving module are respectively installed and fixed on the barrier body, the penetrating part is a hollow structure and/or a notch structure on the barrier body, the barrier body can be a circuit board in practical application, related circuits are printed on the circuit board, and the transmitting module and the receiving module are directly welded on the circuit board; in addition, the outer side of the barrier body is covered with a sleeve, the two reflecting parts are inner side walls (non-specific structures or shapes) of the sleeve, and the sleeve plays a role in protection and water insulation; when the whole assembly is carried out, the requirements on the position relationship between the transmitting module and the reflecting part and the position relationship between the receiving module and the reflecting part are low, so that the assembly efficiency and the production efficiency can be improved, and the yield and the stability and the effectiveness of the device can be improved effectively; in addition, scale is easy to generate after long-time use and is attached to the outer wall of the sleeve, the scale is in contact with liquid to become transparent, and infrared rays can still diffuse into the liquid, so that the detection performance of the device is less influenced by the scale, the defect of the capacitance type liquid level sensor is overcome, the complex and professional debugging caused by water quality difference is avoided, and the production process is simplified.

Therefore, the device has the advantages of simple and reasonable structure, reliable performance, simple processing technology, convenient installation and assembly, low manufacturing cost, high production efficiency and the like; the non-contact liquid level detection device can be widely applied to the fields of equipment with a liquid storage function, household appliances and the like, and comprises a water dispenser, an electric kettle, a coffee machine, an atomizer and the like.

Drawings

FIG. 1 is an assembly view of a non-contact liquid level detecting device according to a first embodiment of the present invention.

Fig. 2 is an exploded view of a non-contact liquid level detection device according to a first embodiment of the present invention.

FIG. 3 is a cross-sectional view of a non-contact liquid level detecting device in a first embodiment of the present invention.

FIG. 4 is a schematic diagram of a partial cross-sectional view of the non-contact liquid level detecting device when the non-contact liquid level detecting device is not immersed in a liquid according to the first embodiment of the present invention.

FIG. 5 is a schematic view, partially in section, of the non-contact liquid level detecting device in the first embodiment of the present invention when the liquid level does not reach the set liquid level height.

FIG. 6 is a schematic view, partly in section, of a non-contact liquid level detection device according to a first embodiment of the invention, when the liquid level exceeds a set level.

Fig. 7 is a sectional view taken in the direction H-H in fig. 3.

Fig. 8 is a cross-sectional view taken along the direction K-K in fig. 7.

FIG. 9 is a schematic electrical diagram of a non-contact liquid level sensing apparatus according to a first embodiment of the present invention.

FIG. 10 is a partial cross-sectional view of a non-contact liquid level sensing device according to a second embodiment of the invention.

FIG. 11 is an assembled view of a non-contact liquid level detecting device according to a third embodiment of the present invention.

FIG. 12 is an exploded view of a non-contact liquid level sensing apparatus according to a third embodiment of the present invention.

FIG. 13 is a cross-sectional view of a non-contact liquid level detecting device in a third embodiment of the present invention.

FIG. 14 is a schematic diagram of a non-contact liquid level detecting device according to a third embodiment of the present invention, partially in cross-section, when the non-contact liquid level detecting device is not immersed in a liquid.

FIG. 15 is a schematic partial sectional view of a non-contact liquid level detecting device in a third embodiment of the present invention, showing the case where the liquid level does not reach the set liquid level height.

FIG. 16 is a schematic view, partly in section, of a non-contact liquid level detection device according to a third embodiment of the invention, when the liquid level exceeds a set liquid level.

FIG. 17 is a schematic diagram of a non-contact liquid level sensing apparatus according to a third embodiment of the present invention.

Detailed Description

The invention is further described with reference to the following figures and examples.

First embodiment

Referring to fig. 1 to 9, the non-contact liquid level detecting device according to the present embodiment includes an emitting module 2 for emitting a sensing ray a, a receiving module 4 for receiving the sensing ray a, a first reflecting part 101, and a second reflecting part 104; the orientation of the transmitting module 2 is not consistent with that of the receiving module 4, the transmitting module 2 corresponds to the first reflecting part 101, and the receiving module 4 corresponds to the second reflecting part 104; a crossing part 301 is arranged between the transmitting module 2 and the receiving module 4; the first reflection part 101 and the second reflection part 104 are oppositely matched with each other; when the liquid level Y1 is lower than the set liquid level height b, the sensing ray a is reflected by the first reflecting part 101, passes through the crossing part 301, is finally reflected by the second reflecting part 104, and reaches the receiving module 4, and an electric signal is provided on the receiving module 4; when the liquid level Y1 reaches or is higher than the set liquid level height b, the sensing ray a is diffused in the liquid Y (specifically, the water body), and no electric signal is generated on the receiving module 4. In the non-contact liquid level detection device in this embodiment, the sensing ray a is reflected between two opposite reflection parts (the first reflection part 101 and the second reflection part 104) (the first reflection part 101 and the second reflection part 104 are not perpendicular), the orientations of the transmitting module 2 and the receiving module 4 are not consistent, and the crossing part 301 between the transmitting module 2 and the receiving module 4 plays a role of limiting part of the sensing ray a to pass through; when the liquid level Y1 does not reach the set liquid level height b, the sensing ray a reflected for multiple times finally reaches the receiving module 4, so that the receiving module 4 generates a corresponding electric signal, and the system judges that the liquid level does not reach the set liquid level height; when the liquid level Y1 reaches or exceeds the set liquid level height b, the sensing ray a diffuses into the liquid Y, the receiving module 4 cannot generate a corresponding electric signal due to the fact that the sensing ray a is not received or the received sensing ray a is insufficient, and the system judges that the liquid level reaches or exceeds the set liquid level height. In the device, the first reflecting part 101 and the second reflecting part 104 do not have rigid angle requirements, so the structure is simple and reasonable, the production process is simplified, and the manufacturing cost is low.

Furthermore, the transmitting module 2 and the receiving module 4 are respectively disposed between the first reflecting part 101 and the second reflecting part 104, in this embodiment, the first reflecting part 101 and the second reflecting part 104 are parallel to each other, the sensing rays a can be reflected for multiple times between the first reflecting part 101 and the second reflecting part 104, and the directions are changed by reflection, so that a plurality of sensing rays a finally reach the receiving module 4 and are received by the receiving module; referring to fig. 3-6, it can be seen that the orientation of the emitting module 2 is opposite to the orientation of the receiving module 4, that is, the emitting end of the emitting module 2 faces the first reflecting portion 101, the receiving end of the receiving module 4 faces the second reflecting portion 104, the sensing ray a needs to be reflected by an effective reflecting surface, and the height position of the liquid level Y1 can directly affect the effectiveness of the emitting surface, so as to achieve the purpose of detecting the liquid level.

Furthermore, the non-contact liquid level detection device further comprises a barrier body 3 for blocking the sensing ray a, the penetrating part 301 is arranged on the barrier body 3, the transmitting module 2 is arranged on one side surface (such as the front side surface) of the barrier body 3, and the receiving module 4 is arranged on the other side surface (such as the back side surface) of the barrier body 3. Specifically, in practical application, the shielding body 3 may be a circuit board (the material of the circuit board is selected from a material capable of shielding and blocking the sensing ray a), the related circuit is printed on the circuit board, the transmitting module 2 and the receiving module 4 are respectively fixed on the circuit board by welding, the penetrating part 301 is directly arranged on the circuit board, and in order to further ensure the shielding performance of the circuit board, a metal membrane for shielding/reflecting the sensing ray a may be selectively added on the circuit board; the transmitting module 2 and the receiving module 4 are distributed up and down.

Further, referring to fig. 7, the penetrating part 301 in the present embodiment is a circular hollow structure on the barrier 3, and the specific shape of the penetrating part 301 is not particularly limited, that is, the shape of the penetrating part 301 may be any regular shape or irregular shape.

Furthermore, the non-contact liquid level detection device further comprises a sleeve 1 which is covered on the outer side of the barrier body 3, the inner cavity of the sleeve 1 is divided into a first accommodating cavity 102 and a second accommodating cavity 103 by the barrier body 3, the transmitting module 2 is arranged in the first accommodating cavity 102, the receiving module 4 is arranged in the second accommodating cavity 103, the penetrating part 301 is arranged between the first accommodating cavity 102 and the second accommodating cavity 103, and the sensing ray a in the first accommodating cavity 102 penetrates through the penetrating part 301 to enter the second accommodating cavity 103; the sensing ray a is reflected more than once in the first accommodating cavity 102, and finally part of the sensing ray a passes through the penetrating part 301 to enter the second accommodating cavity 103, and the sensing ray a is reflected more than once in the second accommodating cavity 103 and finally reaches the receiving module 4.

Further, the sleeve 1 is made of a transparent material, the sleeve 1 in the present embodiment is preferably made of a glass material, the sleeve 1 in the present embodiment is a circular glass tube, the top of the circular glass tube is closed, and the bottom of the circular glass tube is open; the first reflecting part 101 and the second reflecting part 104 are respectively inner side walls of the sleeve 1, and the first reflecting part 101 and the second reflecting part 104 are matched in parallel; when the liquid level Y1 reaches or is higher than the set liquid level height b, the sensing ray a is diffused in the liquid Y through the first reflection part 101 and/or the second reflection part 104; when the liquid level Y1 is lower than the set liquid level height b, the sensing ray a reaches the receiving module 4 after being reflected by the first reflecting part 101 and the second reflecting part 104.

Further, the transmitting module 2 and the receiving module 4 are arranged up and down, and the transmitting module 2 is located above the receiving module 4 (or the transmitting module 2 is located below the receiving module 4); the transmitting module 2, the receiving module 4, the first reflecting part 101 and the second reflecting part 104 are respectively arranged in a liquid storage cavity e for loading liquid Y; receiving module 4 electricity is connected corresponding pilot lamp 6 to through corresponding operating mode of light instruction, when liquid level Y1 did not reach and sets for liquid level height b, corresponding pilot lamp 6 lights, when liquid level Y1 reached or exceeded and set for liquid level height b, corresponding pilot lamp 6 lights, can show corresponding operating mode through the pilot lamp 6 of different colours. Specifically, the upper part of the sleeve 1 extends into the liquid storage cavity e, the transmitting module 2, the receiving module 4 and the penetrating part 301 enter the liquid storage cavity e along with the upper part, the fixing seat 5 is arranged at the bottom end of the sleeve 1, and the non-contact liquid level detection device is fixedly installed on a vessel where the non-contact liquid level detection device is located through the fixing seat 5.

Further, the sensing ray a in this embodiment is an infrared ray (a laser ray or the like may be used according to the actual situation).

Furthermore, the actual position of the set liquid level height b is related to a plurality of parameters such as the position of the transmitting module 2, the position of the receiving module 4, the position of the crossing part 301 and the like; when the parameters are fixed, the actual position of the set liquid level height b can be determined through testing.

Second embodiment

Referring to fig. 10, the non-contact liquid level detection apparatus according to the present embodiment differs from the first embodiment in that: the penetrating part 301 is a gap structure on the barrier body 3; specifically, the penetrating portion 301 is a semicircular notch disposed on one side or both sides of the barrier 3.

The other parts not described are substantially identical to those of the first embodiment and will not be described in detail here.

Third embodiment

Referring to fig. 11-17, the non-contact liquid level detection apparatus according to the present embodiment differs from the first embodiment in that: the emitting module 2 and the receiving module 4 jointly form a group of detecting assemblies c, one or more than two groups of detecting assemblies c are arranged, and a blocking part 302 for intercepting the sensing ray a is arranged between two adjacent groups of detecting assemblies c, so that the sensing ray a is prevented from being received by the receiving module 4 in different detecting assemblies c, and the electric signal is prevented from being generated by mistake. The non-contact liquid level detection device in the embodiment can realize multi-section liquid level detection through a plurality of groups of detection components c.

Further, more than two transmitting modules 2 are connected in parallel with each other, and more than two receiving modules 4 are connected in parallel with each other; the receiving module 4 is electrically connected to the corresponding indicator lamp 6.

The other parts not described are substantially identical to those of the first embodiment and will not be described in detail here.

The foregoing is a preferred embodiment of the present invention, and the basic principles, principal features and advantages of the invention are shown and described. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are intended to illustrate the principles of the invention, but that various changes and modifications may be made without departing from the spirit and scope of the invention, and the invention is intended to be protected by the following claims. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims (10)

1. A non-contact liquid level detection device comprises an emitting module (2) used for emitting sensing rays (a) and a receiving module (4) used for receiving the sensing rays (a); the method is characterized in that: the reflection type LED lamp also comprises a first reflection part (101) and a second reflection part (104); the orientation of the transmitting module (2) is not consistent with the orientation of the receiving module (4), the transmitting module (2) corresponds to the first reflecting part (101), and the receiving module (4) corresponds to the second reflecting part (104); a crossing part (301) is arranged between the transmitting module (2) and the receiving module (4); the first reflection part (101) and the second reflection part (104) are oppositely matched with each other; when the liquid level (Y1) is lower than the set liquid level height (b), the sensing ray (a) passes through the crossing part (301) after being reflected by the first reflecting part (101), and finally reaches the receiving module (4) after being reflected by the second reflecting part (104), and an electric signal is arranged on the receiving module (4); when the liquid level (Y1) reaches or is higher than the set liquid level height (b), the sensing ray (a) is diffused in the liquid (Y), and no electric signal exists on the receiving module (4).

2. The non-contact liquid level detection device of claim 1, wherein: the transmitting module (2) and the receiving module (4) are respectively arranged between the first reflecting part (101) and the second reflecting part (104); the orientation of the transmitting module (2) is opposite to the orientation of the receiving module (4).

3. The non-contact liquid level detection device of claim 1, wherein: still including being used for the check to keep off barrier body (3) of sensing ray (a), pass through portion (301) set up in on barrier body (3), emission module (2) set up in on a side of barrier body (3), receiving module (4) set up in on the another side of barrier body (3).

4. A contactless liquid level detection apparatus according to claim 3, wherein: the penetrating part (301) is a hollow structure and/or a gap structure on the barrier body (3).

5. A contactless liquid level detection apparatus according to claim 3, wherein: the shielding device is characterized by further comprising a sleeve (1) arranged on the outer side of the shielding body (3), the shielding body (3) divides an inner cavity of the sleeve (1) into a first accommodating cavity (102) and a second accommodating cavity (103), the transmitting module (2) is arranged in the first accommodating cavity (102), the receiving module (4) is arranged in the second accommodating cavity (103), the penetrating part (301) is arranged between the first accommodating cavity (102) and the second accommodating cavity (103), and sensing rays (a) in the first accommodating cavity (102) penetrate through the penetrating part (301) to enter the second accommodating cavity (103).

6. The non-contact liquid level detection device of claim 5, wherein: the sleeve (1) is made of a transparent material; the first reflecting part (101) and the second reflecting part (104) are respectively inner side walls of the sleeve (1), and the first reflecting part (101) and the second reflecting part (104) are matched in parallel; when the liquid level (Y1) reaches or is higher than the set liquid level height (b), the sensing ray (a) is diffused in the liquid (Y) through the first reflection part (101) and/or the second reflection part (104); when the liquid level (Y1) is lower than the set liquid level height (b), the sensing ray (a) reaches the receiving module (4) after being reflected by the first reflecting part (101) and the second reflecting part (104).

7. The non-contact liquid level detection device of claim 1, wherein: the transmitting module (2) and the receiving module (4) are arranged up and down; the transmitting module (2), the receiving module (4), the first reflecting part (101) and the second reflecting part (104) are respectively arranged in a liquid storage cavity (e) used for loading liquid (Y).

8. The non-contact liquid level detection device of claim 1, wherein: the sensing ray (a) is an infrared ray or a laser ray.

9. The non-contact liquid level detection device according to any one of claims 1-8, wherein: the emitting module (2) and the receiving module (4) jointly form a group of detection assemblies (c), the detection assemblies (c) are arranged in one group or more than two groups, and a blocking part (302) used for intercepting the sensing rays (a) is arranged between every two adjacent groups of detection assemblies (c).

10. The non-contact liquid level detection device of claim 9, wherein: the more than two transmitting modules (2) are connected in parallel with each other, and the more than two receiving modules (4) are connected in parallel with each other; the receiving module (4) is electrically connected with the corresponding indicator lamp (6).

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