CN112589222A

CN112589222A - Circuit pin soldering device

Info

Publication number: CN112589222A
Application number: CN202011487071.0A
Authority: CN
Inventors: 张慧
Original assignee: Individual
Current assignee: Heshan Zhongfu Xingye Circuit Co ltd
Priority date: 2020-12-16
Filing date: 2020-12-16
Publication date: 2021-04-02
Anticipated expiration: 2040-12-16
Also published as: CN112589222B

Abstract

The invention discloses a circuit pin soldering device, which is characterized in that: the dual-purpose tin soldering device comprises a push soldering module, a tin material module and a pushing module, wherein the tin material module comprises a tin material groove, an electric heating block and a template, the electric heating block is positioned in the tin material groove and used for heating tin materials in the tin material groove to be in a liquid state, the template is fixed at the upper end of the tin material groove, and a jack for inserting a pin of a DIP packaging element is formed in the template.

Description

Circuit pin soldering device

Technical Field

The invention relates to the field of integrated circuit processing equipment, in particular to a circuit pin soldering device.

Background

Dual in-line packages (also called DIP packages or DIP packages), referred to as DIP or DIL for short, are a packaging method for integrated circuits. The CPU chip of the DIP package has two rows of pins and needs to be inserted into a chip socket having a DIP structure. The DIP packaging element can be installed on the circuit board by a through hole insertion technology, and the welding surface of the plug-in electronic circuit board is directly contacted with the high-temperature liquid tin by wave soldering to achieve the purpose of welding. Wave soldering is a process of forming a solder wave with a specific shape on the liquid surface of a solder tank by molten liquid solder under the action of a pump, placing a PCB inserted with components on a transmission chain, and penetrating the solder wave through a certain specific angle and a certain immersion depth to realize welding of a welding point. The components are preheated in a preheating zone of the welding machine during the transport by the chain conveyor (the preheating of the components and the temperature to be achieved are still controlled by a predetermined temperature profile). In actual welding, the preheating temperature of the component surface is also controlled, so that corresponding temperature detection devices (such as infrared detectors) are added to many devices. After preheating, the assembly enters a lead tank for welding. Molten liquid solder is contained in the tin bath, and the wave of deciding the shape is ordered to the butt-joint solder to steel bay bottom nozzle, like this, just is heated by the solder wave when the subassembly welding face passes through the wave, and the solder wave just also wets the soldering area and carries out the extension filling simultaneously, realizes welding process finally. However, the existing wave soldering equipment is complex and high in manufacturing cost, and selective soldering cannot be achieved.

Disclosure of Invention

The invention aims to provide a circuit pin soldering device with lower cost.

The technical scheme adopted by the invention for solving the problems is as follows:

a circuit pin soldering device is characterized in that: the tin material module comprises a tin material groove, an electric heating block and a template, wherein the electric heating block is positioned in the tin material groove and used for heating tin materials in the tin material groove to be liquid, the template is fixed at the upper end of the tin material groove, a jack for inserting a pin of a DIP packaging element is formed in the template, the template is detachably fixed at the upper end of the tin material groove through a bolt, a avoiding hole for inserting the pin of the DIP packaging element is formed in the template, the lower end of the avoiding hole is in a closed state and is in an open state, the push welding module comprises a push welding block, a push welding rod and a push rod pressure spring for upwards jacking the push welding rod, the push welding block is fixed at the lower end of the push welding rod, a sliding hole for slidably mounting the push welding block is formed in the tin material groove, and the sliding hole and the push welding block are in clearance fit, the tin material groove is externally provided with a material collecting bin which is positioned above the sliding hole, an annular heating block is fixed in the material collecting bin, the push welding rod is inserted into the annular heating block and slides on the annular heating block, the push welding block slides downwards along with the push welding rod and enters the tin material groove, so that the liquid level of the liquid tin material in the tin material groove is lifted and extruded into the insertion hole, the liquid tin material is contacted with the welding surface of the circuit board, the pin of the DIP packaging element is welded on the circuit board, the pushing module comprises a first pushing piece for pushing the push rod downwards and a second pushing piece for pushing the push welding rod downwards, the first pushing piece and the second pushing piece sequentially push the push rod and the push welding rod in a working cycle, in one working cycle, the first pushing piece pushes the push rod to sequentially realize sinking, keeping and floating, and the second pushing piece pushes the push welding rod to sequentially realize keeping, Sinking and floating.

Further, as preferred, be fixed with on the template around the peripheral high temperature resistant silica gel sealing washer of jack.

Preferably, the first pushing part and the second pushing part are respectively a first cam and a second cam, the first cam and the second cam are fixed on a rotating shaft, and the rotating shaft is driven to rotate by a servo motor.

Preferably, the first cam is sequentially provided with a first sinking profile section for sinking the mandril, and the central angle of two end points of the first sinking profile section relative to the rotating shaft is 90 degrees; the first profile maintaining section is used for supporting the upper vertex of the ejector rod to enable the ejector rod to maintain the sinking height, and the central angle of two endpoints of the first profile maintaining section relative to the rotating shaft is 180 degrees; the first upper floating profile section enables the ejector rod to float upwards under the action of the ejector rod pressure spring, and the central angle of two end points of the first upper floating profile section relative to the rotating shaft is 90 degrees.

Further, preferably, the second cam is provided with: a second maintaining profile section of the push welding rod is enabled to maintain the floating height under the action of a push welding rod pressure spring, and the central angle of two end points of the second maintaining profile section relative to the rotating shaft is 90 degrees; the second sinking profile section is used for propping the upper vertex of the push welding rod and enabling the push welding rod to sink, and the central angle of two end points of the second sinking profile section relative to the rotating shaft is 180 degrees; and the second upper contour section enables the push welding rod to float upwards under the action of the push rod pressure spring, and the central angle of two end points of the second upper contour section relative to the rotating shaft is 90 degrees.

Preferably, a liquid outlet is formed above the tin trough, the height of the liquid outlet is 0-5 mm higher than that of the upper end of the jack, the liquid outlet is communicated with the adjusting bin, and the upper end of the adjusting bin is communicated with the outside air.

Compared with the prior art, the invention has the following advantages and effects:

(1) through the push away the solder block that sinks in the tin silo downwards for the liquid level of liquid tin uprises, and the liquid level of liquid tin risees the in-process, and liquid tin gets into the jack to the pin of the DIP encapsulation component in the contact jack and the face of weld of circuit board realize the tin soldering, and this process action is simple, and mechanical manufacturing is with low costs.

(2) The method is not only suitable for welding pins of the full-page DIP packaging element, but also suitable for a selective welding scene, and can replace the existing partial wave soldering and selective wave soldering scenes. (the pins of the DIP packaging element needing to be welded are inserted into the jacks, and the pins of the DIP packaging element needing not to be welded are not required to avoid the jacks).

(3) The positioning, welding and resetting actions are realized through 1 rotating shaft, the synchronism of the welding and processing process of the DIP of the circuit board is good, the action links are smoothly connected, the manufacturing cost is low, and the mechanical reliability is high.

(4) According to different circuit board requirements, a template with adaptive jacks is installed, the universality is higher, and the model changing cost is lower.

Drawings

Fig. 1 is a schematic structural view of a DIP soldering apparatus for a circuit board according to an embodiment of the present invention.

Fig. 2 is a schematic structural view of a soldering station according to an embodiment of the present invention.

Fig. 3 is a schematic view of an installation structure of a solder module according to an embodiment of the invention.

Fig. 4 is a schematic structural diagram of a solder module according to an embodiment of the invention.

Fig. 5 is a schematic structural diagram of a propulsion module according to an embodiment of the present invention.

Fig. 6 is a schematic structural view of a first cam according to an embodiment of the present invention.

Fig. 7 is a schematic structural view of a second cam according to the embodiment of the present invention.

Fig. 8 is a schematic diagram of 3 working states of the propulsion module according to the embodiment of the present invention.

Fig. 9 is a schematic diagram of the moving direction of the circuit board according to the embodiment of the invention.

Fig. 10 is a schematic structural diagram of a high temperature resistant silicone sealing ring according to an embodiment of the present invention.

Fig. 11 is a schematic view of an arrangement structure of the avoiding hole according to the embodiment of the present invention.

Fig. 12 is a flow chart of a DIP soldering process for a circuit board according to an embodiment of the present invention.

Reference numerals: the device comprises a conveyor belt 1, a frame 2, a push-welding module 3, a tin material module 4, a clamping module 5, a pushing module 6, a push-welding block 31, a push-welding rod 32, a push rod pressure spring 33, a material collecting bin 34, an annular heating block 35, a tin material groove 41, an electric heating block 42, a shaping plate 43, a jack 44, a bolt 45, a high-temperature-resistant silica gel sealing ring 46, an avoidance hole 47, a liquid outlet 48, an adjusting bin 49, a fixing plate 51, a sleeve 52, an inner rod 53, an upper clamping block 54, a lower clamping block 55, a push rod 56, a push rod pressure spring 57, an upper movable plate 58, a middle movable plate 59, a lower movable plate 510, a locking screw 511, a positioning block 512, a positioning groove 513, a first cam 61, a second cam 62, a rotating shaft 63, a servo motor 64, a first sunken profile section 61, a first maintained profile section 62, a first profile upper raised section 63, a second maintained profile section 621, a second sunken profile section, a second raised section 622, a, a spraying station 81, a preheating station 82, a soldering station 83, a cooling station 84 and tin solder 9

Detailed Description

The present invention will be described in further detail below by way of examples with reference to the accompanying drawings, which are illustrative of the present invention and are not to be construed as limiting the present invention.

Referring to fig. 1 to 10, the DIP soldering apparatus for a circuit board according to the present embodiment includes:

(1) and the spraying station 81 is used for spraying soldering flux on the soldering surface of the circuit board 71.

(2) A preheating station 82, the preheating station 82 being for heating the circuit board 71. After the preheated viscous soldering flux is contacted with the wave soldering tin liquid tin material 9, the activity is sharply increased, the viscosity is sharply reduced, a second diffuse flow is formed on the surface of the metal to be soldered, and the viscous soldering flux is quickly spread on the surface of the metal to be soldered. The preheating method can adopt the existing conventional air convection heating, infrared heater heating or a method of combining hot air and radiation for heating.

(3) And a soldering station 83 for contacting the soldering surface of the circuit board 71 with high temperature liquid tin so that the pins 72 of the DIP package component are soldered to the circuit board 71.

(4) A cooling station 84, wherein the cooling station 84 is used for accelerating solidification of welding points on the welding surface of the circuit board 71. When the welding spot is solidified, the cooling speed of the surface and the cooling speed of the interior of the welding spot are increased, so that tin cracks are formed, tin shrinkage is reduced, and tin holes, pin holes and other defects are formed by exhausting gas from the PCB. After the cooling device is additionally arranged, the cooling speed of the welding spot is accelerated, so that the welding spot is rapidly solidified after being separated from the wave crest, and the occurrence of similar situations is greatly reduced. The cooling station 84 may be a fan type, air curtain type, or compressed air type cooling system used in most wave soldering equipment in the market.

The soldering station 83 is provided with a frame 2, a push welding module 3, a tin material module 4, a clamping module 5 and a pushing module 6,

the tin material module 4 comprises a tin material groove 41, an electric heating block 42 and a template 43, wherein the electric heating block 42 is positioned in the tin material groove 41, the electric heating block 42 is used for heating the tin material 9 in the tin material groove 41 to be liquid, the template 43 is fixed at the upper end of the tin material groove 41, and a jack 44 used for inserting a pin 72 of a DIP packaging element is arranged on the template 43.

The shaping plate 43 is detachably fixed at the upper end of the tin trough 41 through a bolt 45. A high temperature resistant silica gel seal ring 46 surrounding the periphery of the insertion hole 44 is fixed on the template 43. The stencil 43 is provided with a avoiding hole 47 for inserting the pin 72 of the DIP package element, the lower end of the avoiding hole 47 is in a closed state, and the upper end of the avoiding hole 47 is in an open state.

Push away welding module 3 is including push away welding piece 31, push away welding pole 32 and be used for upwards jack-up push rod pressure spring 33 of push away welding pole 32, and push away welding piece 31 is fixed to push away welding pole 32's lower extreme, offer on tin silo 41 and be used for slidable mounting push away welding piece 31's slide opening, slide opening and push away welding piece 31 adopt clearance fit, tin silo 41 outside is provided with the aggregate bin 34, aggregate bin 34 is located the top of slide opening, and the internal fixation of aggregate bin 34 has annular heating piece 35, push away welding pole 32 inserts and establishes the slip on annular heating piece 35. The push-welding block 31 slides downwards along with the push-welding rod 32 and enters the tin groove 41, so that the liquid level of the liquid tin material 9 in the tin groove 41 is lifted and squeezed into the jack 44, the liquid tin material 9 is contacted with the welding surface of the circuit board 71, and the pins 72 of the DIP packaging element are welded on the circuit board 71.

The clamping module 5 comprises a fixed plate 51, sleeves 52, an inner rod 53, an upper clamping block 54, a lower clamping block 55, a push rod 56, a push rod compression spring 57, an upper movable plate 58, a middle movable plate 59 and a lower movable plate 510, wherein at least four sleeves 52 are vertically and slidably mounted on the fixed plate 51, the inner rod 53 is inserted into each sleeve 52, the lower movable plate 510 is fixed at the lower end of each sleeve 52, the upper clamping block 54 is fixed on the lower movable plate 510, the lower end of the inner rod 53 is fixed with a lower clamping block 55, the upper end of the inner rod 53 is fixed with a middle movable plate 59, the upper end of the sleeve 52 is fixed with an upper movable plate 58, the upper movable plate 58 and the middle movable plate 59 are relatively fixed, the lower movable plate 510 is fixed to the lower end of the push rod 56, the push rod 56 is slidably mounted on the fixed plate 51, a push rod pressure spring 57 for pushing up the push rod 56 is sleeved on the push rod 56, and the upper end and the lower end of the push rod pressure spring 57 respectively push against the push rod 56 and the fixed plate 51. When the push rod 56 is pressed downwards, the push rod 56 drives the lower movable plate 510 to slide downwards, so that the soldering surface of the circuit board 71 is pressed against the upper surface of the stencil 43, and the liquid solder 9 extruded into the insertion hole 44 can contact the soldering surface of the circuit board 71, so that the pins 72 of the DIP package component are soldered on the circuit board 71.

The upper movable plate 58 is screwed with a locking screw 511 through a thread, the lower end of the locking screw 511 is rotatably mounted on the middle movable plate 59, and the distance between the upper movable plate 58 and the middle movable plate 59 is adjusted by rotating the locking screw 511, so that the distance between the upper clamping block 54 and the lower clamping block 55 is adjusted, and the circuit board 71 is clamped between the upper clamping block 54 and the lower clamping block 55.

A positioning block 512 in a shape of a circular truncated cone is fixed on the lower movable plate 510, and a positioning groove 513 for inserting the positioning block 512 is formed in the frame 2.

The pushing module 6 comprises a first pushing member for pushing the ejector rod 56 downwards and a second pushing member for pushing the push-welding rod 32 downwards, wherein the first pushing member and the second pushing member sequentially push the ejector rod 56 and the push-welding rod 32 in a working cycle, the first pushing member pushes the ejector rod 56 to sequentially realize sinking, holding and floating in a working cycle, and the second pushing member pushes the push-welding rod 32 to sequentially realize holding, sinking and floating.

The first pushing part and the second pushing part respectively adopt a first cam 61 and a second cam 62, the first cam 61 and the second cam 62 are fixed on a rotating shaft 63, and the rotating shaft 63 is driven to rotate by a servo motor 64.

The first cam 61 is sequentially provided with

(1) A first sunken contour section 61 for sinking the mandril 56, wherein the central angle of two end points of the first sunken contour section 61 relative to the rotating shaft 63 is 90 degrees;

(2) the first maintaining profile section 62 is used for supporting the upper vertex of the ejector rod 56 to enable the ejector rod 56 to maintain the sinking height, and the central angle of two end points of the first maintaining profile section 62 relative to the rotating shaft 63 is 180 degrees;

(3) a first upper contour section 63 which enables the ejector rod 56 to float upwards under the action of the ejector rod pressure spring 57, and the central angle of two end points of the first upper contour section 63 relative to the rotating shaft 63 is 90 degrees.

The second cam 62 is provided with:

(1) the push welding rod 32 is enabled to keep a second profile keeping section 621 with a floating height under the action of a pressure spring of the push welding rod 32, and two end points of the second profile keeping section 621 form a 90-degree angle relative to the central angle of the rotating shaft 63;

(2) a second sinking profile section 622 for pushing against the upper vertex of the push welding rod 32 to sink the push welding rod 32, wherein two end points of the second sinking profile section 622 form a 180-degree angle with respect to the central axis of the rotating shaft 63;

(3) and a second upper contour section 623 which enables the push welding rod 32 to float upwards under the action of the push rod pressure spring 57, wherein the central angle of two end points of the second upper contour section 623 relative to the rotating shaft 63 is 90 degrees.

The upper peak position of the ejector pin 56 is shown as G1 in fig. 8, and the upper peak position of the push-welding rod 32 is shown as G2 in fig. 8. The rotating shaft 63 is driven by the servo motor 64 to rotate 360 degrees to form a working cycle, in one working cycle, the first cam 61 pushes the ejector rod 56 to sequentially sink, keep and float, and the second cam 62 pushes the push welding rod 32 to sequentially keep, sink and float.

A liquid outlet 48 is formed above the tin trough 41, the height of the liquid outlet 48 is 0-5 mm higher than the upper end of the jack 44, and the liquid outlet 48 is communicated with an adjusting bin 49. The upper end of the adjusting bin 49 is communicated to the outside air, the adjusting bin 49 is used for enabling the push-welding block 31 to enter into the tin groove 41 for more volume after the tin liquid reaches the height of the welding surface of the circuit board 71, the tin liquid can enter into the adjusting bin 49 through the liquid outlet 48 to achieve the effect of adjusting the liquid level, and more contact time is provided for the tin liquid to contact with the welding surface of the circuit board 71.

Referring to fig. 12, the process of soldering the DIP on the circuit board of this embodiment includes the following steps:

(1) step S1, a spraying link, namely spraying soldering flux on the welding surface of the circuit board 71;

(2) in step S2, the preheating step is to heat the circuit board 71 by air convection heating or infrared heater heating or a combination thereof.

(3) In step S3, a soldering process is performed to make the soldering surface of the circuit board 71 contact with the high temperature liquid tin, so that the pins 72 of the DIP package component are soldered to the circuit board 71.

(4) And step S4, cooling, namely accelerating solidification of welding points on the welding surface of the circuit board 71 through a cooling system.

In step S3, the liquid tin is stored in the tin trough 41, and the liquid level of the liquid tin is increased by the push-welding block 31 sinking downward into the tin trough 41, and during the increase of the liquid level of the liquid tin, the liquid tin enters the insertion hole 44 and contacts the pin 72 of the DIP package element in the insertion hole 44 and the welding surface of the circuit board 71 to realize soldering.

The step S3 specifically includes the following steps,

(1) step S3.1, the circuit board 71 moves to the upper part of the tin material groove 41 along with the conveyor belt 1,

(2) step S3.2, the circuit board 71 moves vertically downwards under the action of external force, the welding surface of the circuit board 71 is tightly attached to the template 43 at the upper end of the tin trough 41, the pins 72 of the DIP packaging element on the circuit board 71 are synchronously inserted into the jacks 44 on the template 43,

(3) step S3.3, the push-welding block 31 vertically moves downwards under the action of external force and sinks downwards into the tin groove 41, in the process that the liquid level of the liquid tin rises, the liquid tin enters the insertion hole 44 and contacts the pin 72 of the DIP packaging element in the insertion hole 44 and the welding surface of the circuit board 71 to realize tin soldering,

(4) and S3.4, synchronously moving the push welding block 31 and the circuit board 71 upwards under the action of external force to complete resetting, and conveying the circuit board 71 to a cooling link along with the conveyor belt 1.

And the step S3.2 and the step S3.3 are respectively pushed by a cam, and the cam is provided with at least three functional profile sections for respectively realizing the functions of sinking, keeping and rising.

The working time ratio relationship of the step S3.2, the step S3.3 and the step S3.4 is as follows: 1:2:1.

(1) the liquid level of the liquid tin is increased by the push welding block 31 sinking downwards into the tin groove 41, and in the process of increasing the liquid level of the liquid tin, the liquid tin enters the insertion hole 44 and contacts the pin 72 of the DIP packaging element in the insertion hole 44 and the welding surface of the circuit board 71 to realize soldering, so that the process is simple in action and low in mechanical manufacturing cost.

(2) The method is not only suitable for welding the pins 72 of the full-page DIP packaging element, but also suitable for a selective welding scene, and can replace the existing partial wave soldering and selective wave soldering scenes. (pins 72 of the DIP package component that need to be soldered are inserted into the insertion holes 44, and pins 72 of the DIP package component that do not need to be soldered are avoided from the insertion holes 44, as shown in fig. 11).

(3) The positioning, welding and resetting actions are realized through 1 rotating shaft 63, the synchronism of the welding process of the DIP of the circuit board is good, the action links are smoothly connected, the manufacturing cost is low, and the mechanical reliability is high.

(4) According to the requirements of different circuit boards 71, the template 43 with the adaptive jacks 44 is installed, so that the universality is high, and the model changing cost is low.

The above description of the present invention is intended to be illustrative. Various modifications, additions and substitutions for the specific embodiments described may be made by those skilled in the art without departing from the scope of the invention as defined in the accompanying claims.

Claims

1. A circuit pin soldering device is characterized in that: the tin material module comprises a tin material groove, an electric heating block and a template, wherein the electric heating block is positioned in the tin material groove and used for heating tin materials in the tin material groove to be liquid, the template is fixed at the upper end of the tin material groove, a jack for inserting a pin of a DIP packaging element is formed in the template, the template is detachably fixed at the upper end of the tin material groove through a bolt, a avoiding hole for inserting the pin of the DIP packaging element is formed in the template, the lower end of the avoiding hole is in a closed state and is in an open state, the push welding module comprises a push welding block, a push welding rod and a push rod pressure spring for upwards jacking the push welding rod, the push welding block is fixed at the lower end of the push welding rod, a sliding hole for slidably mounting the push welding block is formed in the tin material groove, and the sliding hole and the push welding block are in clearance fit, the tin material groove is externally provided with a material collecting bin which is positioned above the sliding hole, an annular heating block is fixed in the material collecting bin, the push welding rod is inserted into the annular heating block and slides on the annular heating block, the push welding block slides downwards along with the push welding rod and enters the tin material groove, so that the liquid level of the liquid tin material in the tin material groove is lifted and extruded into the insertion hole, the liquid tin material is contacted with the welding surface of the circuit board, the pin of the DIP packaging element is welded on the circuit board, the pushing module comprises a first pushing piece for pushing the push rod downwards and a second pushing piece for pushing the push welding rod downwards, the first pushing piece and the second pushing piece sequentially push the push rod and the push welding rod in a working cycle, in one working cycle, the first pushing piece pushes the push rod to sequentially realize sinking, keeping and floating, and the second pushing piece pushes the push welding rod to sequentially realize keeping, Sinking and floating.

2. The circuit pin soldering apparatus according to claim 1, wherein: and a high-temperature-resistant silica gel sealing ring surrounding the periphery of the jack is fixed on the template.

3. The circuit pin soldering apparatus according to claim 1, wherein: the first pushing part and the second pushing part respectively adopt a first cam and a second cam, the first cam and the second cam are fixed on a rotating shaft, and the rotating shaft is driven to rotate by a servo motor.

4. The circuit pin soldering apparatus according to claim 2, wherein: the first cam is sequentially provided with a first sinking profile section for sinking the mandril, and the central angle of two end points of the first sinking profile section relative to the rotating shaft is 90 degrees; the first profile maintaining section is used for supporting the upper vertex of the ejector rod to enable the ejector rod to maintain the sinking height, and the central angle of two endpoints of the first profile maintaining section relative to the rotating shaft is 180 degrees; the first upper floating profile section enables the ejector rod to float upwards under the action of the ejector rod pressure spring, and the central angle of two end points of the first upper floating profile section relative to the rotating shaft is 90 degrees.

5. The circuit pin soldering apparatus according to claim 2, wherein: the second cam is sequentially provided with: a second maintaining profile section of the push welding rod is enabled to maintain the floating height under the action of a push welding rod pressure spring, and the central angle of two end points of the second maintaining profile section relative to the rotating shaft is 90 degrees; the second sinking profile section is used for propping the upper vertex of the push welding rod and enabling the push welding rod to sink, and the central angle of two end points of the second sinking profile section relative to the rotating shaft is 180 degrees; and the second upper contour section enables the push welding rod to float upwards under the action of the push rod pressure spring, and the central angle of two end points of the second upper contour section relative to the rotating shaft is 90 degrees.

6. The circuit pin soldering apparatus according to claim 1, wherein: and a liquid outlet is formed above the tin trough, the position of the liquid outlet is 0-5 mm higher than the height of the upper end of the jack, the liquid outlet is communicated to the regulating bin, and the upper end of the regulating bin is communicated to the outside air.