Powder conveying system and powder conveying control method

Abstract

The invention relates to a powder conveying system and a powder conveying control method in the technical field of powder conveying, the powder conveying system comprises a pressure distribution and cleaning control module, a pneumatic control module, a powder blending module and a filtering module, two retrograde channels are adopted for powder blending, the two channels work alternately, and the powder suction process and the powder feeding process are completed respectively. A retrograde double-channel powder blending system is adopted for powder blending, the two channels work alternately, the powder suction process and the powder feeding process are completed respectively, and therefore large-amount stable conveying of powder is achieved, an inlet and an outlet of the powder are located at the same end, after the powder is sucked into a filter element space, the powder is retained in the filter element space within a certain time, and when the powder reaches the powder discharging time sequence, the powder is discharged out of the filter element space. Powder feeding gas is blown into the filter element space from the outside of the filter element and pushes powder to enter the main powder outlet, clean air is directly introduced into the opening in the other end of the filter element, and the clean air directly acts on the powder channel and blows the inlet and the outlet respectively.

Description

Technical Field

[0001] The present invention relates to the technical field of powder conveying, and in particular to a powder conveying system and a powder conveying control method, which is a comprehensive control system for conveying powders with high precision, large powder volume and quantitative quantity by using dense phase conveying technology. Background Art

[0002] The principle of electrostatic powder coating is that the powder is fluidized and then transported to the powder coating equipment by the powder pump. The powder coating equipment has a high-voltage power distribution function, which makes the powder carry high-voltage static electricity while atomizing. For coating safety, negative high-voltage spraying is generally adopted. The workpiece is grounded, and the powder with negative high-voltage static electricity is adsorbed to the surface of the workpiece under the combined effect of compressed air, electrostatic adsorption force, and high-voltage electrostatic field force, thereby completing the powder coating.

[0003] An electrostatic powder spraying system mainly consists of a powder spraying room, a powder supply device, one or more powder spraying equipment and controllers, and a recovery device (a primary cyclone recovery device, a secondary filter recovery device, a powder collection device, and a powder conveying device). In the spray powder room, during the powder spraying process, the powder coating is sprayed from the spray gun to the surface of the workpiece. Due to the shape of the workpiece, the spraying stroke, and other reasons, some powder does not adhere to the surface of the workpiece and the resulting powder floats in the air of the powder room. Through the primary cyclone recovery device, it is sucked into the recovery device under the action of the air flow, and then filtered through the secondary filter recovery device. The mixed air is discharged to the outside to complete the powder collection. The collected powder can be transported to the powder supply barrel of the powder supply device by means of a conveying pump, manual transportation, etc., mixed with new powder, and reused for workpiece spraying. The recovered powder can also be directly transported to the waste barrel.

[0004] However, most of the existing powder pumps for conveying powder are Venturi pumps, whose working principle is that after compressed air is sprayed into the Venturi tube, negative pressure will be formed at the inlet of the Venturi tube, and the negative pressure chamber is connected to the fluidized powder barrel. After the powder reaches the inlet of the Venturi tube, it is blown out of the Venturi tube at high speed. The powder is in a state of high-speed suspension in the powder tube at the outlet. If the amount of powder is large, in order to suspend the powder in the powder tube, it is necessary to add a separate compressed air to increase the movement speed and air content of the powder.

[0005] Although the Venturi pump has a simple structure and low cost, there are many disadvantages in using the Venturi pump for conveying. First, the powder conveying speed of the Venturi pump is fast, and the consumption of compressed air is large. Second, the Venturi pump belongs to dilute-phase conveying, and the powder volume is small. To increase the conveyed powder volume, multiple Venturi pumps need to be added, and the diameter of the powder conveying pipe needs to be greatly increased. Third, when the powder conveyed by the Venturi pump is sticky or has poor fluidity, the powder is likely to form a bridge in the cone under the aggregate bucket, resulting in a situation where sometimes no material enters the conveying pipeline and sometimes a large amount of powder gushes out, which is also likely to cause uneven discharging or blockage of the discharging port. Fourth, the pump core of the Venturi pump is extremely easy to wear. The wear of the pump core not only increases the consumables, but also gradually reduces the powder output with the increase of the wear degree, resulting in the powder blockage and inability to be conveyed in time.

[0006] In the past, the dense-phase pump system basically adopted two control methods: one is the single-channel plus air supplement method. The single-channel method has large pulsation and low powder output, and is not suitable for large-scale powder conveying. The other is the forward two-channel method. Although the forward two-channel method can increase the powder output, due to the large wear of the powder on the valve core and filter element, there are many vulnerable parts and the replacement cycle is short. On the other hand, the forward two-channel method cannot automatically clean the pipeline, and the powder color change time is long. If an automatic powder supply system is adopted, a separate cleaning system needs to be configured. Summary of the Invention

[0007] Aiming at the problems of the Venturi pump, the single-channel dense-phase conveying system, and the forward two-channel system dense-phase conveying system commonly used in the above powder conveying, the purpose of this application is to provide a powder conveying system and a powder conveying control method. The present invention uses a reverse two-channel powder distribution system for powder distribution. The two channels work alternately to complete the powder suction and powder delivery processes respectively, so as to achieve stable large-volume powder conveying. The powder inlet and outlet are at the same end. When the powder is sucked into the filter element space, the powder stays in the filter element space for a certain period of time. When it reaches the powder output timing, the powder delivery air is blown into the filter element space from the outside of the filter element and pushes the powder into the total powder outlet. The present invention directly connects clean air at the opening at the other end of the filter element, and the clean air directly acts on the powder passage to blow and sweep the inlet and outlet respectively.

[0008] To achieve the above object, the present invention provides a powder conveying system, including a pressure distribution and cleaning control module, a pneumatic control module, a powder distribution module, and a filtering module; The filtering module is used for storing powder and includes a left filter element and a right filter element. The left filter element has a left filter element valve chamber and a left filter element air cavity, and the right filter element has a right filter element valve chamber and a right filter element air cavity; The powder blending module is used to achieve reverse dual-channel powder delivery, including a left powder blending unit, a right powder blending unit, a total powder inlet, and a total powder outlet. The left powder blending unit includes a left suction valve core and a left discharge valve core. The feeding end of the left suction valve core is connected to the total powder inlet through a left powder inlet pipe, and the discharging end of the left suction valve core is connected to the left filter element valve chamber of the left filter element through a left powder suction pipe. The feeding end of the left discharge valve core is connected to the left filter element valve chamber of the left filter element through a left powder blowing pipe, and the discharging end of the left discharge valve core is connected to the total powder outlet through a left powder outlet pipe. The right powder blending unit includes a right suction valve core and a right discharge valve core. The feeding end of the right suction valve core is connected to the total powder inlet through a right powder inlet pipe, and the discharging end of the right suction valve core is connected to the right filter element valve chamber of the right filter element through a right powder suction pipe. The feeding end of the right discharge valve core is connected to the right filter element valve chamber of the right filter element through a right powder blowing pipe, and the discharging end of the right discharge valve core is connected to the total powder outlet through a right powder outlet pipe. The left suction valve core and the right discharge valve core are connected through a valve core pneumatic control A path, and the left discharge valve core and the right discharge valve core are connected through a valve core pneumatic control B path; The pneumatic control module is used to cooperate with the upper computer to implement the control logic of the powder blending module, including a negative pressure adjustment component, a powder feeding air adjustment component, a valve core air adjustment component, a left powder control switching valve, and a right powder control switching valve. The negative pressure adjustment component is respectively connected to the left filter element air chamber of the left filter element and the right filter element air chamber of the right filter element through the left powder control switching valve and the right powder control switching valve. The powder feeding air adjustment component is respectively connected to the left powder control switching valve and the right powder control switching valve. The valve core air adjustment component is respectively connected to the left suction valve core, the left discharge valve core, the right suction valve core, and the right discharge valve core; The pressure delivery and cleaning control module is used to provide the required air supply pressure for the powder blending module and the filtration module, including a total air inlet pipe and a cleaning air switch valve. One path of the total air inlet pipe is connected to the powder feeding air adjustment component, and the other path of the total air inlet pipe is respectively connected to the left filter element valve chamber of the left filter element and the right filter element valve chamber of the right filter element through the cleaning air switch valve.

[0009] To facilitate the realization of negative pressure inside the left filter element and the right filter element, preferably, the negative pressure adjustment component includes a negative pressure generator, a negative pressure switch valve, and a negative pressure regulating valve. The negative pressure regulating valve is respectively connected to the total air inlet pipe and the negative pressure switch valve. The negative pressure switch valve is connected to the negative pressure generator. The negative pressure generator is respectively connected to the left powder control switching valve and the right powder control switching valve.

[0010] To facilitate the control of the powder feeding air pressure, preferably, the powder feeding air adjustment component includes a powder feeding air regulating valve and a powder feeding air control valve. The powder feeding air regulating valve is respectively connected to the total air inlet pipe and the powder feeding air control valve. The powder feeding air control valve is respectively connected to the total air inlet pipe, the left powder control switching valve, and the right powder control switching valve.

[0011] To facilitate the control of powder suction and powder feeding for each valve core, preferably, the valve core air regulating assembly includes a valve core air pressure regulating valve and a valve core air control valve. The valve core air pressure regulating valve is respectively connected to the main inlet pipe and the valve core air control valve, and the valve core air control valve is respectively connected to the left suction valve core, the left outlet valve core, the right suction valve core, and the right outlet valve core.

[0012] To facilitate the cleaning within each module, the cleaning air switch valve is connected to the left filter element valve chamber of the left filter element through the left cleaning air path, and a left one-way valve is provided on the left cleaning air path. The cleaning air switch valve is connected to the right filter element valve chamber of the right filter element through the right cleaning air path, and a right one-way valve is provided on the right cleaning air path.

[0013] Since increasing the proportion of the powder suction time will increase the powder suction amount and vice versa, preferably, the inlet pressure range of the negative pressure generator adjusted by the negative pressure regulating valve is 0.3 - 0.5 MPa.

[0014] To reduce the consumption of compressed air, powder pipe wear, etc., the smaller the better. According to the powder output, the diameter and length of the powder outlet pipe, the powder feeding air pressure range controlled by the powder feeding air pressure regulating valve is preferably 0.15 - 0.35 MPa.

[0015] The present invention also provides a powder conveying control method for the above powder conveying system. The powder conveying control method uses a reverse dual-channel for powder blending. The two channels work alternately to complete the powder suction and powder feeding processes respectively. The negative pressure regulating assembly controls the powder suction and powder feeding of the left filter element and the right filter element. The powder feeding air pressure regulating valve and the powder feeding air control valve of the powder feeding air regulating assembly control the powder feeding air pressure. The valve core air regulating assembly controls the powder suction and powder feeding of the left suction valve core, the left outlet valve core, the right suction valve core, and the right outlet valve core; During the powder suction stage of the left channel, the powder enters the left powder inlet pipe from the main powder inlet. The left suction valve core opens, and the powder enters the left powder suction pipeline along the left suction valve core and finally enters the left filter element valve chamber of the left filter element; During the powder feeding stage of the left channel, the powder is blown into the left powder blowing pipe from the left filter element valve chamber. At the same time, the left outlet valve core opens and the left suction valve core closes. The powder enters the left powder outlet pipe along the left outlet valve core and finally is sent out from the main powder outlet to the supply material bucket or the waste powder bucket; During the powder suction stage of the right channel, the powder enters the right powder inlet pipe from the main powder inlet. The right suction valve core opens, and the powder enters the right powder suction pipeline along the right suction valve core and finally enters the right filter element valve chamber of the right filter element; During the powder feeding stage of the right channel, the powder is blown into the right powder blowing pipe from the right filter element valve chamber. At the same time, the right outlet valve core opens and the right suction valve core closes. The powder enters the right powder outlet pipe along the right outlet valve core and finally is sent out from the main powder outlet to the supply material bucket or the waste powder bucket; The powder suction and powder feeding of the left filter element and the right filter element operate alternately; During the powder suction stage of the left filter element and the right filter element, the negative pressure regulating component controls the negative pressure of the left powder-air control pipe and the right powder-air control pipe. The negative pressure acts on the left filter element valve chamber and the right filter element valve chamber through the left filter element air cavity and the right filter element air cavity respectively to complete powder suction; During the powder feeding stage of the left filter element and the right filter element, the powder feeding air regulating component passes positive pressure into the left powder-air control pipe and the right powder-air control pipe through the left powder control switching valve and the right powder control switching valve. The positive pressure air blows out the powder sucked into the left filter element valve chamber and the right filter element valve chamber, thus completing a working cycle; In the first stage of cleaning, the cleaning air enters from the main inlet pipe, enters the left powder control switching valve and the right powder control switching valve through the powder feeding air control valve, and then enters the left filter element air cavity and the right filter element air cavity to circulate and clean the powder in the left filter element and the right filter element; In the second stage of cleaning, the cleaning air enters from the main inlet pipe, enters the left filter element valve chamber and the right filter element valve chamber through the cleaning air switch valve, and cleans the entire system from the upper ends of the left filter element and the right filter element.

[0016] During cleaning, the left suction valve core, the left outlet valve core, the right suction valve core, and the right outlet valve core still work alternately. The cleaning air and the powder feeding air are turned on at the same time to achieve pulse cleaning.

[0017] In summary, the present invention has the following beneficial effects: (1) The present invention adopts the dense-phase conveying technology, which solves a series of problems such as low flow rate, large air consumption, high flow velocity, unstable flow rate, frequent replacement of vulnerable parts, and complex cleaning in Venturi conveying; (2) Since the present invention adopts a reverse double-channel, the purging air is directly blown into the powder conveying channel from one end of the filter element, enabling the system itself to have a high-efficiency and fast cleaning ability without an additional cleaning system; (3) In the reverse double-channel system, when the powder is sucked into the valve chamber of the filter element, the powder speed gradually decreases, and the powder speed drops to zero within a certain period of time after reaching the filter element valve chamber, thus avoiding the wear of the valve core and the filter element and prolonging the service life of the device; (4) The present invention simplifies the control logic, reduces the use of electrical components, and adds a segmented cleaning logic; during cleaning, first, the powder feeding air blows from the outside of the filter element at high pressure, and then the powder feeding air and the cleaning air are turned on at the same time for pulse cleaning, thus avoiding the situation where the powder contaminates the filter element due to high-pressure purging, and the pulse cleaning makes the gas volume in a single pipeline larger and the cleaning cleaner. Description of the Drawings

[0018] Figure 1 is the system function partition diagram of the powder conveying system of the present invention; Figure 2 is the system schematic diagram of the powder conveying system of the present invention. Detailed Embodiments

[0019] The following elaborates on the preferred embodiments of the present invention in conjunction with the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making the protection scope of the present invention more clearly defined.

[0020] As Figure 1 shown in the powder conveying system, it is divided into four different functional zones in total.

[0021] Among them, Zone A is the pressure distribution and cleaning control module. This zone mainly supplies the required air supply pressure to the intake pipelines of each module. To cooperate with necessary process actions, the pressure distribution in Zone A can be achieved by arranging a pressure regulating valve and a three-way valve in parallel to form multi-stage pressure air supply (as shown in the present invention), or a proportional valve can be used for air supply, and different pressure paths can be selected according to process requirements.

[0022] Zone B is the pneumatic control module, which is the pneumatic control logic area. This area mainly cooperates with the host computer program to implement the necessary control logic of the dense phase system, including powder suction, powder feeding, cleaning, etc.

[0023] Zone C is the powder dispensing module, which is the powder metering valve system of the dense phase system. This zone has four pinch valves, which are opened or closed according to logic to achieve the control of powder inlet and outlet.

[0024] Zone D is the filtration module, which consists of two filter elements and one-way valves. The inner cavity of the filter element is the powder storage area, and the inhaled powder is stored in this space for a short time. The outer cavity of the filter element is connected to the pneumatic control module in Zone B, and negative pressure and positive pressure air are alternately supplied. Negative pressure air is used to suck powder from the inlet, and positive pressure is used to blow out powder at a certain speed. One end of the inner cavity of the filter element is connected to the cleaning air. When cleaning and ventilation are required, the entire powder pipeline can be quickly purged from the inner cavity.

[0025] Specifically, as combined with Figure 2 shown, the filtration module in Zone D includes a left filter element 102 and a right filter element 103. The left filter element 102 has a left filter element valve chamber 301 and a left filter element air chamber 202 inside. The left filter element air chamber 202 is located outside the left filter element valve chamber 301. The right filter element 103 has a right filter element valve chamber 302 and a right filter element air chamber 203 inside. The right filter element air chamber 203 is located outside the right filter element valve chamber 302; Specifically, the powder blending module in area C includes a left powder blending unit, a right powder blending unit, a total powder inlet 311, and a total powder outlet 312. The left powder blending unit includes a left suction valve core 105 and a left discharge valve core 106. The feed end of the left suction valve core 105 is connected to the total powder inlet 311 through a left powder inlet pipe 307, and the discharge end of the left suction valve core 105 is connected to the left filter element valve chamber 301 of the left filter element 102 through a left powder suction pipe 303. The feed end of the left discharge valve core 106 is connected to the left filter element valve chamber 301 of the left filter element 102 through a left powder blowing pipe 304, and the discharge end of the left discharge valve core 106 is connected to the total powder outlet 312 through a left powder outlet pipe 309. The right powder blending unit includes a right suction valve core 107 and a right discharge valve core 108. The feed end of the right suction valve core 107 is connected to the total powder inlet 311 through a right powder inlet pipe 308, and the discharge end of the right suction valve core 107 is connected to the right filter element valve chamber 302 of the right filter element 103 through a right powder suction pipe 305. The feed end of the right discharge valve core 108 is connected to the right filter element valve chamber 302 of the right filter element 103 through a right powder blowing pipe 306, and the discharge end of the right discharge valve core 108 is connected to the total powder outlet 312 through a right powder outlet pipe 310. Additionally, the left suction valve core 105 and the right discharge valve core 108 are connected through a valve core pneumatic control A path 207, and the left discharge valve core 106 and the right suction valve core 107 are connected through a valve core pneumatic control B path 208; Specifically, the pneumatic control module includes a negative pressure regulating component, a powder feeding air regulating component, a valve core air regulating component, a left powder control switching valve 110, and a right powder control switching valve 111; Among them, the negative pressure regulating component includes a negative pressure generator 112, a negative pressure switch valve 114, and a negative pressure regulating valve 115. The negative pressure regulating valve 115 is respectively connected to the total air inlet pipe 216 and the negative pressure switch valve 114. The negative pressure switch valve 114 is connected to the negative pressure generator 112. The negative pressure generator 112 is connected to the left powder control switching valve 110 through a left negative pressure air path 209, and the negative pressure generator 112 is connected to the right powder control switching valve 111 through a right negative pressure air path 210; Among them, the powder feeding air regulating component includes a powder feeding air regulating valve 116 and a powder feeding air control valve 113. The inlet end of the powder feeding air regulating valve 116 is connected to the total air inlet pipe 216. The outlet end of the powder feeding air regulating valve 116 is connected to the powder feeding air control valve 113 through a total powder feeding air path 214. The inlet end of the powder feeding air control valve 113 is connected to the total air inlet pipe 216 through a filter element air cavity cleaning air path 215. One outlet end of the powder feeding air control valve 113 is connected to the left powder control switching valve 110 through a left powder feeding air path 211, and the other outlet end of the powder feeding air control valve 113 is connected to the right powder control switching valve 111 through a right powder feeding air path 212; Among them, the valve core air regulation assembly includes a valve core air pressure regulating valve 117 and a valve core air control valve 109. The inlet end of the valve core air pressure regulating valve 117 is connected to the main inlet pipe 216. The outlet end of the valve core air pressure regulating valve 117 is connected to the valve core air control valve 109 through the valve core control air path 213. The valve core air control valve 109 sucks the left valve core 105 and the right outlet valve core 108 through the valve core air control A path 207. The valve core air control valve 109 is connected to the left outlet valve core 106 and the right suction valve core 107 through the valve core air control B path 208. Among them, the pressure distribution and cleaning control module includes a main inlet pipe 216 and a cleaning air switch valve 118. One path of the main inlet pipe 216 is connected to the powder feeding air regulation assembly, and the other path of the main inlet pipe 216 is connected to the cleaning air switch valve 118. The cleaning air switch valve 118 is connected to the left filter element valve chamber 301 of the left filter element 102 through the left cleaning air path 201, and a left one-way valve 101 is arranged on the left cleaning air path 201. The cleaning air switch valve 118 is connected to the right filter element valve chamber 302 of the right filter element 103 through the right cleaning air path 204, and a right one-way valve 104 is arranged on the right cleaning air path 204.

[0026] The powder conveying control method and principle of the above powder conveying system are as follows: The powder path of the present invention is divided into two related left and right systems, and powder distribution is carried out by using a reverse double channel. The double channels work alternately to complete the powder suction and powder feeding processes respectively; In the powder suction stage of the left channel, the left suction valve core 105, the left outlet valve core 106 and the left filter element 102 form the left side powder distribution. The powder enters the left powder inlet pipe 307 from the main powder inlet 311. When the left suction valve core 105 is opened, it enters the left powder suction pipeline 303 along the left suction valve core 105 and finally enters the internal space left filter element valve chamber 301 of the left filter element 102; In the powder feeding stage of the left channel, the powder is blown into the left powder blowing pipe 304 from the left filter element valve chamber 301. At the same time, the left outlet valve core 106 is opened and the left suction valve core 105 is closed. The powder enters the left powder outlet pipe 309 along the left outlet valve core 106 and is finally sent out from the main powder outlet 312 to the supply material bucket or the waste powder bucket; In the powder suction stage of the right channel, the right suction valve core 107, the right outlet valve core 108 and the right filter element 103 form the right side powder distribution. The powder enters the right powder inlet pipe 308 from the main powder inlet 311. When the right suction valve core 107 is opened, it enters the right powder suction pipeline 305 along the right suction valve core 107 and finally enters the internal space right filter element valve chamber 302 of the right filter element 103; In the powder feeding stage of the right channel, the powder is blown into the right powder blowing pipe 306 from the right filter element valve chamber 302. At the same time, the right outlet valve core 108 is opened and the right suction valve core 107 is closed. The powder enters the right powder outlet pipe 309 along the right outlet valve core 108 and is finally sent out from the main powder outlet 312 to the supply material bucket or the waste powder bucket.

[0027] The switching of the four valve cores is controlled by a two-position five-way valve core pneumatic control valve 109. Since the powder feeding systems on the left and right sides will not suck or discharge powder simultaneously, when the left side sucks powder, the right side discharges powder, and when the left side discharges powder, the right side sucks powder. Therefore, the left suction valve core 105 and the right discharge valve core 108 form a group of passage valve core pneumatic control A path 207, and the left discharge valve core 106 and the right suction valve core 107 form a group of passage valve core pneumatic control B path 208. According to the control logic, this valve moves in a non-overlapping and cyclic manner. The four valve cores are made of rubber-like materials. The clamping force of the valve core is provided by air pressure, and the opening force of the valve core is provided by its own resilience. Therefore, the pneumatic control passages of the valve core, such as the pneumatic control A path 207 and the pneumatic control B path 208 of the valve core, need to have two states, one is the inflation and pressurization state, and the other is the evacuation state. The two inlets of the pneumatic control valve controlling the valve core need to be connected to the positive pressure of the pinch valve and the atmosphere respectively.

[0028] The left filter element 102 and the right filter element 103 have two working states, one is the powder suction state and the other is the powder feeding state. In the powder suction state, the left powder pneumatic control pipe 205 and the right powder pneumatic control pipe 206 are introduced with negative pressure. The negative pressure acts on the left filter element valve chamber 301 and the right filter element valve chamber 302 inside the two filter elements through the left filter element air chamber 202 and the right filter element air chamber 203 respectively, and cooperates with the opening and closing of the valve core to complete the powder suction action. In the powder feeding state, the left powder pneumatic control pipe 205 and the right powder pneumatic control pipe 206 are introduced with positive pressure. The positive pressure air passes through the filter element wall and blows out the powder sucked into the valve chamber, thus completing a working cycle. It can be seen from this that the overall working state of the filter element is that powder suction and powder feeding alternate. In order to prevent the filter element from being blocked after long-term operation, the absolute pressure of powder suction of the filter element here should be less than the absolute pressure of powder feeding. Since the maximum negative pressure that the negative pressure generator 112 can generate is generally 0.07 MPa, the pressure of the powder feeding air is generally greater than 0.1 MPa.

[0029] The negative pressure regulating valve 115 adjusts the inlet pressure of the negative pressure generator 112, and the general pressure range is 0.3 - 0.5 MPa. By adjusting the on-time of the negative pressure switch valve 114, the powder suction amount of a single channel is adjusted. Increasing the proportion of the powder suction time will increase the powder suction amount, and vice versa. The negative pressure generator 112 is respectively connected to the left negative pressure air path 209 to the left powder control switching valve 110 and the right negative pressure air path 210 to the right powder control switching valve 111 to provide a negative pressure source for the filter element.

[0030] The powder feeding air pressure regulating valve 116 is used to regulate the powder feeding air pressure. According to different working states, the powder feeding air pressure also needs to be adjusted. In the normal powder feeding state, the powder feeding air pressure only needs to meet the powder transportation requirement. To reduce the consumption of compressed air and the wear of the powder pipe, the smaller the better. According to the powder output, the diameter and length of the powder pipe, the preferred range is between 0.15 - 0.35 MPa. In the powder distribution working state, the adjusted powder feeding air enters the total powder feeding air path 214, enters the powder feeding air control valve 113, and then enters the left powder feeding air path 211 and the right powder feeding air path 212 respectively. Through the left powder control switching valve 110 and the right powder control switching valve 111, it reaches the left filter element air cavity 202 and the right filter element air cavity 203. The left powder control switching valve 110 and the right powder control switching valve 111 alternately switch between positive pressure and negative pressure according to the time sequence to complete the powder suction and powder feeding actions of the filter element.

[0031] The cleaning working state is divided into two stages. In the first stage, the cleaning air enters from the total air inlet pipe 216 into the filter element air cavity cleaning air path 215, and successively enters the powder feeding air control valve 113, the left powder feeding air path 211, the right powder feeding air path 213, the left powder control switching valve 110, the right powder control switching valve 111, the left powder air control 205, the right powder air control 206, and reaches the left filter element air cavity 202 and the right filter element air cavity 203 to circulate and clean the powder in the two filter elements for at least 5 seconds. In the second stage, the cleaning air enters from the total air inlet pipe 216 into the cleaning air switch valve 118, enters the left cleaning air path 201 and the right cleaning air path 204, opens the left one-way valve 101 and the right one-way valve 104, and cleans the entire system from the upper end of the filter element. When the cleaning is in progress, the four valve cores still work alternately, and the cleaning air and the powder feeding air are opened simultaneously and pulsed for cleaning. This cleaning method not only prevents the filter element from being polluted when cleaning the high-pressure pipeline, but also has a simple cleaning logic, and the pulsed cleaning can ensure that the powder path is cleaner.

[0032] It should be noted that in the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installation", "connection", "connection", "setting", "provided with", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0033] The above are all the preferred embodiments of this application. The protection scope of this application is not limited by this. Therefore, all equivalent changes made according to the structure, shape, principle and application direction of this application should be covered within the protection scope of this application.

Claims

1. A powder conveying system, characterized in that: It includes a pressure distribution and cleaning control module, a pneumatic control module, a powder dispensing module, and a filtering module; The filtering module is used to store powder and includes a left filter element (102) and a right filter element (103). The left filter element (102) has a left filter element valve chamber (301) and a left filter element air chamber (202) inside, and the right filter element (103) has a right filter element valve chamber (302) and a right filter element air chamber (203) inside; The powder dispensing module is used to achieve reverse two-channel powder dispensing and includes a left powder dispensing unit, a right powder dispensing unit, a total powder inlet (311), and a total powder outlet (312). The left powder dispensing unit includes a left suction valve core (105) and a left discharge valve core (106). The feed end of the left suction valve core (105) is connected to the total powder inlet (311) through a left powder inlet pipe (307), and the discharge end of the left suction valve core (105) is connected to the left filter element valve chamber (301) of the left filter element (102) through a left powder suction pipe (303). The feed end of the left discharge valve core (106) is connected to the left filter element valve chamber (301) of the left filter element (102) through a left powder blowing pipe (304), and the discharge end of the left discharge valve core (106) is connected to the total powder outlet (312) through a left powder outlet pipe (309). The right powder dispensing unit includes a right suction valve core (107) and a right discharge valve core (108). The feed end of the right suction valve core (107) is connected to the total powder inlet (311) through a right powder inlet pipe (308), and the discharge end of the right suction valve core (107) is connected to the right filter element valve chamber (302) of the right filter element (103) through a right powder suction pipe (305). The feed end of the right discharge valve core (108) is connected to the right filter element valve chamber (302) of the right filter element (103) through a right powder blowing pipe (306), and the discharge end of the right discharge valve core (108) is connected to the total powder outlet (312) through a right powder outlet pipe (310). The left suction valve core (105) is connected to the right discharge valve core (108) through a valve core pneumatic control A path (207), and the left discharge valve core (106) is connected to the right suction valve core (107) through a valve core pneumatic control B path (208); The pneumatic control module is used to cooperate with the upper computer to implement the control logic of the powder dispensing module and includes a negative pressure adjustment component, a powder feeding air adjustment component, a valve core air adjustment component, a left powder control switching valve (110), and a right powder control switching valve (111). The negative pressure adjustment component is respectively connected to the left filter element air chamber (202) of the left filter element (102) and the right filter element air chamber (203) of the right filter element (103) through the left powder control switching valve (110) and the right powder control switching valve (111). The powder feeding air adjustment component is respectively connected to the left powder control switching valve (110) and the right powder control switching valve (111). The valve core air adjustment component is respectively connected to the left suction valve core (105), the left discharge valve core (106), the right suction valve core (107), and the right discharge valve core (108); The pressure distribution and cleaning control module is used to provide the required air supply pressure for the powder dispensing module and the filtering module, and includes a main inlet pipe (216) and a cleaning air switch valve (118). One path of the main inlet pipe (216) is connected to the powder feeding air regulating assembly, and the other path of the main inlet pipe (216) is respectively connected to the left filter element valve chamber (301) of the left filter element (102) and the right filter element valve chamber (302) of the right filter element (103) through the cleaning air switch valve (118).

2. The powder conveying system according to claim 1, wherein: The negative pressure regulating assembly includes a negative pressure generator (112), a negative pressure switch valve (114) and a negative pressure regulating valve (115). The negative pressure regulating valve (115) is respectively connected to the main inlet pipe (216) and the negative pressure switch valve (114). The negative pressure switch valve (114) is connected to the negative pressure generator (112), and the negative pressure generator (112) is respectively connected to the left powder control switching valve (110) and the right powder control switching valve (111).

3. The powder conveying system according to claim 2, characterized in that: The powder feeding air regulating assembly includes a powder feeding air regulating valve (116) and a powder feeding air control valve (113). The powder feeding air regulating valve (116) is respectively connected to the main inlet pipe (216) and the powder feeding air control valve (113). The powder feeding air control valve (113) is respectively connected to the main inlet pipe (216), the left powder control switching valve (110) and the right powder control switching valve (111).

4. The powder conveying system according to claim 3, wherein: The valve core air regulating assembly includes a valve core air regulating valve (117) and a valve core air control valve (109). The valve core air regulating valve (117) is respectively connected to the main inlet pipe (216) and the valve core air control valve (109). The valve core air control valve (109) is respectively connected to the left suction valve core (105), the left discharge valve core (106), the right suction valve core (107) and the right discharge valve core (108).

5. The powder conveying system according to claim 4, wherein: The cleaning air switch valve (118) is connected to the left filter element valve chamber (301) of the left filter element (102) through the left cleaning air path (201), and a left one-way valve (101) is arranged on the left cleaning air path (201). The cleaning air switch valve (118) is connected to the right filter element valve chamber (302) of the right filter element (103) through the right cleaning air path (204), and a right one-way valve (104) is arranged on the right cleaning air path (204).

6. The powder conveying system according to claim 5, characterized in that: The negative pressure regulating valve (115) adjusts the inlet pressure range of the negative pressure generator (112) to be 0.3 - 0.5 MPa.

7. The powder conveying system according to claim 5, wherein: The powder feeding air pressure controlled by the powder feeding air regulating valve (116) ranges from 0.15 to 0.35 MPa.

8. A powder conveying control method for the powder conveying system according to any one of claims 1-7, characterized in that, The powder conveying control method uses a reverse double-channel for powder dispensing. The two channels work alternately to complete the powder suction and powder feeding processes respectively. The negative pressure regulating assembly controls the powder suction and powder feeding of the left filter element (102) and the right filter element (103). The powder feeding air regulating valve (116) and the powder feeding air control valve (113) of the powder feeding air regulating assembly control the powder feeding air pressure. The valve core air regulating assembly controls the powder suction and powder feeding of the left suction valve core (105), the left discharge valve core (106), the right suction valve core (107) and the right discharge valve core (108); In the left-channel powder suction stage, the powder enters the left powder inlet pipe (307) from the main powder inlet (311). The left suction valve core (105) opens, and the powder enters the left powder suction pipeline (303) along the left suction valve core (105), and finally enters the left filter element valve chamber (301) of the left filter element (102). In the left-channel powder feeding stage, the powder is blown into the left powder blowing pipe (304) from the left filter element valve chamber (301). At the same time, the left outlet valve core (106) opens, and the left suction valve core (105) closes. The powder enters the left powder outlet pipe (309) along the left outlet valve core (106), and finally is sent out from the main powder outlet (312) to the supply material bucket or the waste powder bucket. In the right-channel powder suction stage, the powder enters the right powder inlet pipe (308) from the main powder inlet (311). The right suction valve core (107) opens, and the powder enters the right powder suction pipeline (305) along the right suction valve core (107), and finally enters the right filter element valve chamber (302) of the right filter element (103). In the right-channel powder feeding stage, the powder is blown into the right powder blowing pipe (306) from the right filter element valve chamber (302). At the same time, the right outlet valve core (108) opens, and the right suction valve core (107) closes. The powder enters the right powder outlet pipe (309) along the right outlet valve core (108), and finally is sent out from the main powder outlet (312) to the supply material bucket or the waste powder bucket. The powder suction and feeding of the left filter element (102) and the right filter element (103) operate alternately. In the powder suction stage of the left filter element (102) and the right filter element (103), the negative pressure of the left powder-air control pipe (205) and the right powder-air control pipe (206) is controlled by the negative pressure regulating component. The negative pressure acts on the left filter element valve chamber (301) and the right filter element valve chamber (302) through the left filter element air cavity (202) and the right filter element air cavity (203) respectively to complete powder suction. In the powder feeding stage of the left filter element (102) and the right filter element (103), the powder feeding air regulating component passes positive pressure into the left powder-air control pipe (205) and the right powder-air control pipe (206) through the left powder control switching valve (110) and the right powder control switching valve (111). The positive pressure air blows out the powder sucked into the left filter element valve chamber (301) and the right filter element valve chamber (302), thus completing a working cycle. In the first stage of cleaning, the cleaning air enters from the main air inlet pipe (216), enters the left powder control switching valve (110) and the right powder control switching valve (111) through the powder feeding air control valve (113), and then enters the left filter element air cavity (202) and the right filter element air cavity (203) to circulate and clean the powder in the left filter element (102) and the right filter element (103). In the second stage of cleaning, the cleaning air enters from the main air inlet pipe (216), enters the left filter element valve chamber (301) and the right filter element valve chamber (302) through the cleaning air switch valve (118), and cleans the whole system from the upper ends of the left filter element (102) and the right filter element (103). When cleaning, the left suction valve core (105), the left outlet valve core (106), the right suction valve core (107), and the right outlet valve core (108) still work alternately. The cleaning air and the powder feeding air are opened at the same time to realize pulse cleaning.

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