CN216632599U - Closed-loop negative-pressure powder circulating system and laser sintering equipment - Google Patents

Abstract

The application provides a closed loop negative pressure powder circulation system and laser sintering equipment, circulation system include negative pressure pump, pressure release subassembly, first separator, first storage powder spare and send powder spare. The pressure relief assembly comprises an exhaust pipe, a pressure relief valve and a one-way valve, wherein the pressure relief valve and the one-way valve are arranged on the exhaust pipe, the exhaust pipe is communicated with an air outlet of the negative pressure pump, and the one-way valve only allows fluid in the exhaust pipe to be discharged outwards. The first separation chamber of the first separator is communicated with the air outlet of the negative pressure pump, and the air outlet of the first separator is communicated with the air suction port of the negative pressure pump. The discharge hole of the first powder storage part is communicated with a pipeline communicated with the first separation chamber and the air outlet of the negative pressure pump. The powder feeding piece is communicated with a discharge hole of the first separator. The powder circulating system of the embodiment adopts closed-loop negative pressure powder feeding, so that the oxygen content of the system is stable, and the product molding is facilitated; the powder is not easy to leak, and is safe and reliable.

Description

Closed-loop negative-pressure powder circulating system and laser sintering equipment

Technical Field

The utility model relates to the technical field of 3D (three-dimensional) forming, in particular to a closed-loop negative-pressure powder circulating system and laser sintering equipment.

Background

The selective laser sintering is an advanced manufacturing technology with the distinct characteristics of digital manufacturing, high flexibility and adaptability, direct CAD model driving, rapidness, rich and various material types and the like, and has become a supporting technology in the modern advanced manufacturing technology since the development of the end of the eighties of the twentieth century to the present. The sintering process of the selective laser sintering equipment comprises powder supply, powder recovery and powder post-treatment. At present, the powder supply and the powder recovery of small selective laser sintering equipment generally adopt a manual operation mode, and an operator manually detaches and replaces a powder supply and recovery tank body in the sintering process. In the application of large selective laser sintering equipment, a positive pressure powder conveying mode is generally adopted, the mode is easy to cause pipeline powder blockage and air return pipelines to carry a large amount of backflow powder conveying, sintering termination and powder waste are caused, and meanwhile, environmental safety hazards also exist.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a closed-loop negative-pressure powder circulating system and laser sintering equipment, which can reduce powder waste, reduce potential safety hazards and improve the operation safety.

The embodiment of the utility model is realized by the following steps:

in a first aspect, the present invention provides a closed loop negative pressure powder circulation system, comprising:

a negative pressure pump;

the pressure relief assembly comprises an exhaust pipe, a pressure relief valve and a one-way valve, wherein the pressure relief valve and the one-way valve are arranged on the exhaust pipe, the exhaust pipe is communicated with an air outlet of the negative pressure pump, and the one-way valve only allows fluid in the exhaust pipe to be discharged outwards;

the first separation chamber of the first separator is communicated with the air outlet of the negative pressure pump, and the air outlet of the first separator is communicated with the air suction port of the negative pressure pump;

the discharge hole of the first powder storage part is communicated with a pipeline which is communicated with the first separation chamber and the air outlet of the negative pressure pump;

and the powder feeding piece is communicated with a discharge hole of the first separator.

In an optional embodiment, a first valve is arranged on a pipeline between an air outlet of the first separator and an air suction port of the negative pressure pump; a pipeline between the first valve and the air suction port of the negative pressure pump is provided with an air delivery hole which can be opened or closed; and a pipeline between the first valve and the air outlet of the first separator is provided with an air outlet which can be opened or closed.

In an alternative embodiment, the closed loop negative pressure powder circulation system further comprises a filter, which is disposed between the suction port of the negative pressure pump and the air outlet of the first separator, and is used for filtering the fluid flowing from the first separator to the negative pressure pump.

In an optional embodiment, two first separators are provided, a second valve is provided at the gas inlet of each first separator, a third valve is provided at the gas outlet of each first separator, and a fourth valve is provided at the discharge outlet of each first separator; each first separator is provided with a first gas transmission hole capable of being switched between an opening state and a closing state, and the first gas transmission holes are used for introducing inert gas into the first separation chambers so as to enable powder in the corresponding first separation chambers to enter the powder feeding pieces.

In an optional embodiment, the discharge hole of the first powder storage part is provided with a fifth valve.

In an optional embodiment, the closed-loop negative-pressure powder circulating system further comprises a second separator, a screening device and a second powder storage part, wherein a second separation chamber of the second separator is communicated with an air outlet of the negative pressure pump, an air outlet of the second separator is communicated with an air suction port of the negative pressure pump, a discharge port of the second separator is communicated with the screening device, the screening device is communicated with the first powder storage part, and a sixth valve is arranged between the screening device and the first powder storage part; the second powder storage part is used for receiving the overflowing powder of the working chamber, and a discharge hole of the second powder storage part is communicated with a pipeline between an air outlet of the negative pressure pump and the second separation chamber; a seventh valve is arranged on a pipeline between the discharge hole of the second powder storage part and the air outlet of the negative pressure pump; and an eighth valve is arranged on a pipeline between the discharge hole of the first powder storage part and the gas outlet of the negative pressure pump.

In an alternative embodiment, the number of the second separators is two, and a ninth valve is arranged at the air inlet of each second separator; a tenth valve is arranged at the gas outlet of each second separator, and an eleventh valve is arranged at the discharge hole of each second separator; each second separator is provided with a second gas transmission hole capable of being switched between an opening state and a closing state, and the second gas transmission holes are used for introducing inert gas into the second separation chambers so that powder in the corresponding second separation chambers can enter the screener.

In an optional embodiment, the closed-loop negative-pressure powder circulating system further comprises a powder post-treatment part, an outlet of the powder post-treatment part is communicated with a pipeline between an air inlet of the second separator and an air suction port of the negative pressure pump, a twelfth valve is arranged on a pipeline between a connection part of the second separator and the powder post-treatment part and the air suction port of the negative pressure pump, and a thirteenth valve is arranged on a pipeline between a connection part of the second separator and the powder post-treatment part; and an inlet of the powder post-processing part is communicated with an air outlet of the negative pressure pump, and a fourteenth valve is arranged on a pipeline for communicating the inlet of the powder post-processing part and the air outlet of the negative pressure pump.

In an optional embodiment, level meters are arranged on the first separator, the first powder storage part, the powder feeding part, the second separator and the second powder storage part.

In a second aspect, the present invention provides a laser sintering apparatus comprising:

the closed loop negative pressure powder circulation system of any of the preceding embodiments.

The embodiment of the utility model has the beneficial effects that:

in summary, the closed-loop negative-pressure powder circulation system provided by this embodiment isolates the powder from the outside air in the process of conveying the powder in a closed-loop manner, so that no air is mixed into the powder, and the oxygen content of the system pipeline is stable; the negative pressure is adopted to convey the powder, so that the condition of powder spraying outside can be avoided, the air environment is not easily polluted, and the safety in the powder conveying process is very high. Specifically, in the powder conveying process, the pressure release valve is in a continuous opening state and used for discharging redundant gas when the negative pressure pump vacuumizes the front end pipeline. The check valve is located one side of the gas outlet of the pressure release valve, when powder in the first powder storage part enters the pipeline from the discharge port, the powder falling position of the pipeline is blocked by the powder, the negative pressure pump continuously vacuumizes the front end pipeline, very large negative pressure is formed in the front end pipeline, meanwhile, very large positive pressure is generated on the rear end pipeline of the negative pressure pump, and redundant gas in the pipeline is discharged from the exhaust pipe through the pressure release valve. When powder at the powder falling position of the pipeline is pulled by negative pressure in the pipeline at the front end of the negative pressure pump, the negative pressure on the pipeline at the front end of the negative pressure pump and positive pressure on the pipeline at the rear end of the negative pressure pump are exchanged at the moment, the powder can be displaced towards the air suction port of the negative pressure pump, and gas in the pipeline at the rear end of the negative pressure pump flows towards the air suction port of the negative pressure pump along with the powder, so that the pipeline at the rear end of the negative pressure pump is instantly converted into negative pressure from positive pressure, and because a pressure release valve on an exhaust pipe is in an open state, and one side of an air outlet of the pressure release valve is provided with a one-way valve, the one-way valve plays a role in preventing the back suction phenomenon of the exhaust pipe, and further prevents external air from entering the pipeline of the system and influencing the oxygen content of the system, namely, the embodiment adopts closed-loop negative pressure powder feeding to stabilize the oxygen content of the system and is beneficial to product forming; the powder is not easy to leak, and is safe and reliable.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a schematic flow chart of a closed-loop negative-pressure powder circulation system according to an embodiment of the present invention.

Icon:

100-a negative pressure pump; 101-a pressure relief assembly; 1011-an exhaust pipe; 1012-pressure relief valves; 1013-one-way valves; 102-first separator a; 1021-a first gas transfer port; 103-first separator b; 1031-second gas transmission hole; 104-second separator a; 105-a second separator b; 106-a filter; 107-a filter; 108-a first powder storage; 109-a second powder storage part; 110-powder feeding piece; 111-powder post-treatment part; 112-suction pipe; 113-an air outlet pipe; 114-a feed pipe; 115-a discharge pipe; 116-a first level gauge; 117-first leg; 118-a second leg; 119-a third branch; 120-a second level gauge; 121-a third level gauge; 122-a fourth level gauge; 123-a fifth level indicator; 124-slag discharge tank; 125-a pressure sensor; 126-a sixth level gauge; 127-a level meter; 128-a level-loading gauge; 129-a level down gauge; 130-a seventh level indicator; 131-a fourth branch; 132-a fifth branch; 133-sixth leg; 134-a third gas transfer port; 135-fourth gas transfer port; 136-an eighth level indicator; 137-a ninth level indicator; 138-a tenth level gauge; 139-an eleventh level gauge; 140-a first oxygen sensor; 141-a second oxygen sensor; 142-a powder suction pipe; 143-inlet pipe; 144-evacuation pipe; 145-gas delivery pipe.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the utility model, as claimed, but is merely representative of selected embodiments of the utility model. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or orientations or positional relationships that the products of the present invention are conventionally placed in use, and are only for convenience of describing the present invention and simplifying the description, but do not indicate or imply that the device or element to which the description refers must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another, and are not to be construed as indicating or implying relative importance.

Furthermore, the terms "horizontal", "vertical" and the like do not imply that the components are required to be absolutely horizontal or pendant, but rather may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

At present, in a selective laser sintering system, a powder conveying system has two powder conveying modes, wherein one mode is closed-loop positive-pressure powder conveying, and the other mode is open-loop negative-pressure powder conveying. The closed-loop positive pressure powder feeding mode adopts positive pressure in the pipeline, and when leakage occurs in the pipeline, powder can be sprayed out from the leakage position, so that environmental pollution is caused. And the powder is sent to the open-loop negative pressure, and pipe-line system and outside air intercommunication, and the difficult stable control of oxygen content in the system, and thoughtlessly have air in the pipeline, have great potential safety hazard.

In view of this, designers have designed a closed-loop negative-pressure powder feeding circulation system, which not only can realize the stable control of the oxygen content, but also is not easy to mix air in a pipeline system and has high safety; meanwhile, the condition of powder spraying is not easy to occur, and the environment is not easy to be polluted.

Referring to fig. 1, in the present embodiment, the closed-loop negative pressure powder circulation system includes a negative pressure pump 100, a pressure relief assembly 101, a first separator a102, a first separator b103, a second separator a104, a second separator b105, a sieving device 106, a filter 107, a first powder storage component 108, a second powder storage component 109, a powder feeding component 110, a powder post-processing component 111, a plurality of pipelines, a plurality of valves, a plurality of sensors, a plurality of level meters, and the like. The negative pressure pump 100, the first separator a102, the second separator b105, the first powder storage part 108, the powder feeding part and the filter 107 form a powder feeding circulation structure together; the negative pressure pump 100, the second separator a104, the second separator b105, the sifter 106, the first powder storage member 108, the second powder storage member 109, the sifter 106, and the filter 107 together constitute a powder recovery circulation structure. The negative pressure pump 100, the second separator a104, the second separator b105, the filter 107, and the powder post-treatment member 111 together constitute a powder post-treatment circulation structure.

Alternatively, the negative pressure pump 100 is provided as a vacuum pump. The negative pressure pump 100 has a suction port and an air outlet, and a line communicating with the suction port of the vacuum pump is referred to as a front-end line, and a line communicating with the air outlet of the vacuum pump is referred to as a rear-end line. When the vacuum pump works, the front end pipeline is vacuumized to generate negative pressure, so that the fluid in the pipeline has the tendency of flowing towards the air suction port; correspondingly, the back end tubing is positively pressurized and the fluid has a tendency to enter the tubing through the exit orifice. Meanwhile, an air suction pipe 112 is connected to an air suction opening of the negative pressure pump 100, a valve a is arranged on the air suction pipe 112, an air outlet 113 is connected to an air outlet of the negative pressure pump 100, and a valve b is arranged on the air outlet 113.

Optionally, the pressure relief assembly 101 includes an exhaust pipe 1011, a pressure relief valve 1012 and a one-way valve 1013. The exhaust pipe 1011 is communicated with the exhaust pipe 113, the pressure release valve 1012 and the check valve 1013 are both provided on the exhaust pipe 1011, and the check valve 1013 is located on one side of the gas outlet of the pressure release valve 1012, that is, when the pressure in the pipeline system is too high, the excess gas in the gas sucked into the negative pressure pump 100 from the gas suction port can be discharged from the exhaust pipe 1011 after entering the exhaust pipe 113. When the excess gas is discharged, the gas is first pushed open by the relief valve 1012 and then discharged from the check valve 1013. The purpose of the check valve 1013 is to allow only gas to be exhausted from the exhaust pipe 1011 when the gas flows from the vacuum pump to the exhaust pipe 1011, and external air does not flow through the exhaust pipe 1011 from the check valve 1013 and enter the vacuum pump, that is, during the operation of the closed-loop negative pressure powder circulation system, no external air enters the pipeline system, and the oxygen content in the pipeline system is stable.

Optionally, the first powder storage 108 is a tank, a feeding pipe 114 and a discharging pipe 115 are arranged on the first powder storage 108, a valve c is arranged on the feeding pipe 114, and a valve d and a first level indicator 116 are arranged on the discharging pipe 115. One end of the discharge pipe 115 is communicated with the gas outlet pipe 113. The powder feeding amount of the first powder storing member 108 can be adjusted by controlling the opening frequency of the valve c.

Alternatively, both the first separator a102 and the first separator b103 may be provided as cyclone separators. The first separator a102 and the first separator b103 each have a separation chamber, and a discharge port and a gas outlet which are communicated with the separation chamber, that is, after a fluid formed by mixing gas and powder is introduced into the separation chamber, the gas and the powder are separated in the separation chamber, the gas enters the suction pipe 112 from the gas outlet, and the powder is conveyed to the powder storage member. Specifically, the outlet pipe 113 is communicated with the first separation chamber a and the first separation chamber b through two first branch pipes 117, and is used for conveying the powder from the first powder storage part 108 to the first separation chamber a and the first separation chamber b through air flow. A valve e is provided in the first branch pipe 117 communicating with the first separation chamber a, and a valve f is provided in the first branch pipe 117 communicating with the first separation chamber b. The gas outlet of the first separator a102 and the gas outlet of the first separator b103 are respectively communicated with the gas suction pipe 112 through two second branch pipes 118, a valve g is arranged on the second branch pipe 118 communicated with the gas outlet of the first separator a102, and a valve h is arranged on the second branch pipe 118 communicated with the gas outlet of the first separator b 103. Meanwhile, the discharge port of the first separator a102 and the discharge port of the first separator b103 are respectively communicated with the powder feeding part 110 through two third branch pipes 119, a valve i is arranged on the third branch pipe 119 communicated with the discharge port of the first separator a102, and a valve j is arranged on the third branch pipe 119 communicated with the discharge port of the first separator b 103. Further, a first air delivery hole 1021 capable of being opened and closed is provided at a side of the first separator a102 opposite to the discharge port, and a second air delivery hole 1031 capable of being opened and closed is provided at a side of the first separator b103 opposite to the discharge port. In the powder feeding process, the first separator a102 and the first separator b103 alternately operate, so that powder continuously falls into the first powder feeding member, and in the powder feeding process, gas meeting the pressure requirement is input into the separators through the first gas transmission hole 1021 and the second gas transmission hole 1031 respectively, so that the powder separated in the corresponding separator can smoothly fall into the first powder feeding member.

Further, a second level gauge 120 and a third level gauge 121 are disposed on the first separator a102, and the second level gauge 120 is located below the third level gauge 121. The first separator b103 is provided with a fourth level gauge 122 and a fifth level gauge 123, respectively, and the fourth level gauge 122 is located below the fifth level gauge 123.

Optionally, the filter 107 is disposed in the suction pipe 112, and an inlet and an outlet of the filter 107 are both communicated with the suction pipe 112, that is, the gas flowing out of the first separator a102 and the first separator b103 needs to flow through the filter 107 for filtering and then enter the vacuum pump, so as to prevent the vacuum pump from being polluted and damaged. Meanwhile, an evacuation pipe 144 is provided on the filter 107, and the evacuation pipe 144 can be opened or closed by a valve. Meanwhile, a gas pipe 145 is provided on a pipe section of the gas suction pipe 112 between the filter 107 and the negative pressure pump 100, and a valve capable of opening and closing is provided on the gas pipe 145. Further, a slag outlet of the filter 107 is communicated with the slag discharge tank 124, and a valve v is arranged between the slag outlet and the slag discharge tank 124. Further, a pressure sensor 125 and a sixth level gauge 126 are provided on the filter 107.

In this embodiment, the operation flow of the powder feeding circulation structure includes, for example:

the powder feeding circulation structure is a negative pressure closed loop powder feeding structure. Before the separation and transportation, the system needs to be evacuated so that the oxygen content in the system is within a set range. Specifically, the pressure relief valve 1012, the valve a, the valve b, the valve d, the valve i and the valve j are closed, then the emptying pipe 144 is opened, the inert gas is input from the gas pipe 145, enters the negative pressure pump 100 and then enters the gas outlet pipe 113 from the gas outlet, flows to the filter 107 from the gas suction pipe 112 after passing through the first separator a102 and the first separator b103, and then is discharged from the emptying pipe 144, the first oxygen sensor 140 is arranged on the filter 107, the oxygen content in the pipeline is monitored in real time through the first oxygen sensor 140, and when the requirement is met, the gas pipe 145 and the emptying pipe 144 are closed, so that the emptying operation of the system pipeline is completed. Then, during the powder transportation process, the pressure release valve 1012 is in a continuously open state, and is used for discharging excess gas when the vacuum pump is used for vacuumizing the suction pipe 112. The check valve 1013 is located at one side of the gas outlet of the pressure release valve 1012, when the powder in the first powder storage part 108 enters the gas outlet pipe 113 from the discharge port, the powder falling position of the pipeline is blocked by the powder, and the vacuum pump continues to vacuumize the gas inlet pipe 112, so that a very large negative pressure is formed in the gas inlet pipe 112, and at the same time, the gas outlet pipe 113 of the vacuum pump generates a very large positive pressure, and the excess gas in the pipeline is discharged from the gas outlet pipe 1011 through the pressure release valve 1012. When powder at the powder falling position of the pipeline is pulled by negative pressure in the air suction pipe 112 of the vacuum pump, the negative pressure on the air suction pipe 112 of the vacuum pump and positive pressure on the air outlet pipe 113 of the vacuum pump are exchanged at the moment, the powder can be displaced towards the air suction port of the vacuum pump, and gas in the air outlet pipe 113 of the vacuum pump flows towards the air suction port of the vacuum pump along with the powder, so that the air outlet pipe 113 of the vacuum pump is instantly converted into negative pressure from positive pressure, and because the pressure release valve 1012 on the air outlet pipe 1011 is in an open state, and one side of the air outlet of the pressure release valve 1012 is provided with the one-way valve 1013, the one-way valve 1013 plays a role of preventing the back suction phenomenon of the air outlet pipe 1011, and further preventing external air from entering the pipeline of the system and influencing the oxygen content of the system, that is to say, the embodiment adopts closed-loop negative pressure to send powder, so that the oxygen content of the system is stable and the product molding is facilitated; the powder is not easy to leak, and is safe and reliable. It should be understood that the front end pipe may be understood as a pipe between the suction port of the negative pressure pump 100 and the powder falling position of the pipe, and the rear end pipe may be understood as a pipe between the air outlet port of the negative pressure and the powder falling position of the pipe. It should be understood that the powder enters the powder feeding member 110 from the discharge port after passing through the first separator a102 and the second separator b105 while the powder and the gas are mixed and flowing toward the suction port. The gas is discharged into the suction pipe 112.

Optionally, the powder feeding member 110 is provided with a level gauge 127, a feeding level gauge 128 and a discharging level gauge 129, the feeding level gauge 128 is located above the discharging level gauge 129, and the level gauge 127 is located at the top of the powder feeding member 110.

It should be noted that, when the system is in a standby state, all the valves are in a closed state, the negative pressure pump 100 is not started, and the powder feeding component and the level meters on the first separator a102 and the first separator b103 monitor the powder state and determine whether to start the closed-loop negative pressure powder conveying function. Particularly, by the alternate operation of the first separator a102 and the second separator b105, continuous powder feeding can be realized, and the efficiency can be improved. Specifically, the first separator a102 is first operated as an example. The process is as follows:

the valves e and g on the first separator a102 are opened, the negative pressure pump 100 is started, the valve d discharges the powder in the first powder storage part 108 into the gas outlet pipe 113 in a pulse opening and closing mode to form pipeline blockage, the negative pressure pump 100 vacuumizes the gas inlet pipe 112, the pressure relief valve 1012 at the rear end of the negative pressure pump 100 is opened to discharge gas, the generated negative pressure adsorbs and conveys the powder into the first separator a102, the powder is settled through the cyclone separation structure in the first separator a102, the gas returns to the negative pressure pump 100 through the filter 107, and the redundant gas is discharged through the pressure relief valve 1012 at the rear end of the negative pressure pump 100. When the signal of the third level gauge 121 on the first separator a102 is turned on, the second separator a104 opens the valve f and the valve h, the powder in the pipeline is simultaneously adsorbed and conveyed to the first separator a102 and the first separator b103, after the system lasts for several seconds, the first separator a102 is closed, after the action is finished, the system opens the valve i of the first separator a102 with the third level gauge 121 turned on, and simultaneously the first air delivery hole 1021 at the top of the first separator a102 is opened, the air is conveyed into the first separator a102 by positive pressure, the powder in the first separator a102 falls into the powder conveying piece, and after the signal of the second level gauge 120 on the first separator a102 is turned off, the system closes the valve i below the first separator a 102. After the signal of the third level indicator 121 on the first separator a102 is lighted, the system opens the valve e and the valve g on the first separator a102 after powder falling is finished again, the two separators are simultaneously adsorbed and conveyed with powder, after the system lasts for a plurality of seconds, the valve f and the valve h of the first separator b are closed, the last separator powder falling action is repeated, thus, the system alternately switches the two separators of the first separator a102 and the first separator b103 to adsorb and convey powder and powder falling to the powder conveying piece 110 until the signals of the third level indicator 121 on the first separator a102, the fifth level indicator 123 on the first separator b103, the material loading level indicator 128 on the powder conveying piece and the level indicator 127 on the powder conveying piece are all lighted, the valve d is closed, powder conveying is stopped, the negative pressure pump 100 is continuously started for a plurality of seconds, the valves a and b are closed, the valve e and the valve g on the first separator a102 are closed, And the valve g and the valves f and h on the first separator b103 are closed, and the pressure relief valve 1012 at the rear end of the negative pressure pump 100 is closed, so that the action of automatically closing the loop to adsorb and convey the powder by the negative pressure of the system is completed.

In this embodiment, optionally, the second powder storage part 109 is configured as a tank, and the second powder storage part 109 is used for collecting powder overflowing after powder spreading in the working chamber is completed. The seventh level gauge 130 is disposed on the second powder storage member 109. Meanwhile, the bottom of the second powder storage part 109 is provided with a pipeline communicated with the air outlet pipe 113, the pipeline is provided with a valve k, meanwhile, a valve l is also arranged between the second powder storage part 109 and the negative pressure pump 100, when the powder feeding circulation is carried out, the valve l is closed, and gas discharged from the air outlet of the negative pressure pump 100 cannot flow to the second powder storage part 109.

In this embodiment, optionally, the second separator a104 and the second separator b105 are both provided as cyclone separators. The second separator a104 and the second separator b105 each have a separation chamber, and a discharge port and a gas outlet which are communicated with the separation chamber, that is, after a fluid formed by mixing gas and powder is introduced into the separation chamber, the gas and the powder are separated in the separation chamber, the gas enters the suction pipe 112 from the gas outlet, and the powder is conveyed to the powder storage member. Specifically, the gas outlet pipe 113 is respectively communicated with the second separation chamber a and the second separation chamber b through two fourth branch pipes 131, and is used for conveying the powder from the second powder storage part 109 to the second separation chamber a and the second separation chamber b through gas flow. A valve m is provided in the fourth branch pipe 131 communicating with the second separation chamber a, and a valve n is provided in the fourth branch pipe 131 communicating with the second separation chamber b. The gas outlet of the second separator a104 and the gas outlet of the second separator b105 are respectively communicated with the gas suction pipe 112 through two fifth branch pipes 132, the fifth branch pipe 132 communicated with the gas outlet of the second separator a104 is provided with a valve o, the fifth branch pipe 132 communicated with the gas outlet of the second separator b105 is provided with a valve p, and the valve o and the valve p are closed when the powder feeding circulation is carried out. Meanwhile, the discharge port of the second separator a104 and the discharge port of the second separator b105 are respectively communicated with the sifter 106 through two sixth branch pipes 133, and the sifter 106 is communicated with the first powder storage member 108 through the feeding pipe 114. Meanwhile, a valve q is provided in the sixth branch pipe 133 communicating with the discharge port of the second separator a104, and a valve r is provided in the sixth branch pipe 133 communicating with the discharge port of the second separator b 105. Further, a third transfer port 134 which can be opened and closed is provided at a side of the second separator a104 opposite to the discharge port, and a fourth transfer port 135 which can be opened and closed is provided at a side of the second separator b105 opposite to the discharge port. In the powder feeding process, the second separator a104 and the second separator b105 alternately operate, so that the powder continuously falls into the first powder feeding member, and in the powder feeding process, gas meeting the pressure requirement is input into the separators through the third gas transmission hole 134 and the fourth gas transmission hole 135 respectively, so that the powder separated from the corresponding separators can smoothly fall into the first screening device 106. Note that the alternate operation of the second separator a104 and the second separator b105 is the same as the operation of the first separator a102 and the first separator b103, and detailed description thereof is omitted in this embodiment.

Further, an eighth level gauge 136 and a ninth level gauge 137 are provided on the second separator a104, and the eighth level gauge 136 is located below the ninth level gauge 137. The second separator b105 is provided with a tenth level gauge 138 and an eleventh level gauge 139, respectively, and the tenth level gauge 138 is located below the eleventh level gauge 139.

Further, a second oxygen sensor 141 is provided on the sifter 106.

In this embodiment, it should be noted that the operation flow of the powder recycling structure includes, for example:

valve b, valve h and valve g are all closed, and valve l is open. Then, the evacuation operation is performed, and the evacuation operation is stopped when the second oxygen sensor 141 detects that the oxygen content of the piping system is within the set range. Then, the negative pressure pump 100 operates to generate negative pressure in the suction pipe 112 connected to the second separator a104 and the second separator b105, to suck out the powder in the second powder storage 109 and convey the powder to the second separator a104 or the second separator b105, after the powder and the gas are separated, the powder falls into the sieving machine 106 to be sieved, and the sieved powder can enter the first powder storage 108 to participate in the powder conveying cycle. And the gas flows back to the suction port. It should be understood that the amount of powder delivered from the second powder reservoir 109 can be controlled by controlling the frequency of opening of the valve k.

Further, a valve s is further disposed on the air outlet pipe 113, and after the valve s is closed, the air outlets of the second separator a104 and the second separator b105 are blocked from the air outlet of the negative pressure pump 100. During the powder post-treatment cycle, the valve s is closed.

In this embodiment, optionally, the powder post-processing part 111 is a tank, a powder suction pipe 142 and an air inlet pipe 143 are disposed on the powder post-processing part 111, the powder suction pipe 142 is communicated with a pipe section of the air suction pipe 112 between the valve s and the fourth branch pipe 131, a valve t is disposed on the powder suction pipe 142, and the valve t is closed when a powder recovery cycle is performed. The inlet pipe 143 is communicated with the outlet pipe 113, and a valve u is provided on the inlet pipe 143, and is closed when the powder feeding circulation and the powder recovery circulation are performed.

In this embodiment, the operation flow of the powder post-treatment circulation structure includes, for example:

when the valve l, the valve b and the valve s are closed, when the molding cylinder is transferred to the lower part of the working chamber, the powder suction pipe 142 is inserted into the powder post-processing part 111, the valve t on the powder suction pipe 142 is opened, the negative pressure pump 100 is started, negative pressure is generated in the air suction pipe 112, under the negative pressure, powder in the powder post-processing part 111 is directly adsorbed and conveyed to the second separator a104 and the second separator b105 by using the powder suction pipe 142, the alternate operation flow of the second separator a104 and the second separator b105 is the same as that of the first separator a102 and the first separator b103, after the powder and gas enter the second separator a104 and the second separator b105, the powder and the gas are separated by the cyclone separation structure, the powder enters the sieving device 106 and then enters the first powder storage part 108, and can participate in the next powder conveying circulation.

In this embodiment, it should be noted that the valve a, the valve b, the valve c, the valve d, the valve e, the valve f, the valve g, the valve h, the valve i, the valve g, the valve k, the valve l, the valve m, the valve n, the valve o, the valve p, the valve q, the valve r, the valve s, the valve t, and the valve u may be stop valves, and the stop valves are controlled to open and close in a pulse manner.

The closed-loop negative pressure powder circulating system provided by the embodiment can realize powder feeding circulation, powder recovery circulation and powder post-treatment circulation, and is a closed-loop negative pressure operation mode, the oxygen content of the system is stable and reliable, the powder is not easy to leak, the environment is not easy to pollute, and the safety is high.

The embodiment also provides laser sintering equipment which comprises the closed-loop negative-pressure powder circulating system, wherein the powder feeding part is communicated with the powder feeding mechanism of the working chamber, the second powder storage part 109 is communicated with the powder overflowing cylinder, and the powder post-processing part 111 is communicated with the forming cylinder.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A closed loop negative pressure powder circulation system is characterized by comprising:

a negative pressure pump;

the pressure relief assembly comprises an exhaust pipe, a pressure relief valve and a one-way valve, wherein the pressure relief valve and the one-way valve are arranged on the exhaust pipe, the exhaust pipe is communicated with an air outlet of the negative pressure pump, and the one-way valve only allows fluid in the exhaust pipe to be discharged outwards;

the first separation chamber of the first separator is communicated with the air outlet of the negative pressure pump, and the air outlet of the first separator is communicated with the air suction port of the negative pressure pump;

the discharge hole of the first powder storage part is communicated with a pipeline which is communicated with the first separation chamber and the air outlet of the negative pressure pump;

and the powder feeding piece is communicated with a discharge hole of the first separator.

2. The closed loop negative pressure powder circulation system of claim 1, wherein:

a first valve is arranged on a pipeline between the air outlet of the first separator and the air suction port of the negative pressure pump; a pipeline between the first valve and the air suction port of the negative pressure pump is provided with an air delivery hole which can be opened or closed; and a pipeline between the first valve and the air outlet of the first separator is provided with an air outlet which can be opened or closed.

3. The closed loop negative pressure powder circulation system of claim 1, wherein:

the closed-loop negative-pressure powder circulating system further comprises a filter, wherein the filter is arranged between an air suction port of the negative-pressure pump and an air outlet of the first separator and is used for filtering fluid flowing from the first separator to the negative-pressure pump.

4. The closed loop negative pressure powder circulation system of claim 1, wherein:

the number of the first separators is two, a second valve is arranged at the air inlet of each first separator, a third valve is arranged at the air outlet of each first separator, and a fourth valve is arranged at the discharge outlet of each first separator; each first separator is provided with a first gas transmission hole capable of being switched between an opening state and a closing state, and the first gas transmission holes are used for introducing inert gas into the first separation chambers so as to enable powder in the corresponding first separation chambers to enter the powder feeding pieces.

5. The closed loop negative pressure powder circulation system of claim 1, wherein:

and a fifth valve is arranged at the discharge hole of the first powder storage part.

6. The closed loop negative pressure powder circulation system of any one of claims 1-5, wherein:

the closed-loop negative-pressure powder circulating system further comprises a second separator, a screening device and a second powder storage part, a second separation chamber of the second separator is communicated with an air outlet of the negative pressure pump, the air outlet of the second separator is communicated with an air suction port of the negative pressure pump, a discharge port of the second separator is communicated with the screening device, the screening device is communicated with the first powder storage part, and a sixth valve is arranged between the screening device and the first powder storage part; the second powder storage part is used for receiving the overflowing powder of the working chamber, and a discharge hole of the second powder storage part is communicated with a pipeline between an air outlet of the negative pressure pump and the second separation chamber; a seventh valve is arranged on a pipeline between the discharge hole of the second powder storage part and the air outlet of the negative pressure pump; and an eighth valve is arranged on a pipeline between the discharge port of the first powder storage part and the air outlet of the negative pressure pump.

7. The closed-loop negative pressure powder circulation system of claim 6, wherein:

the number of the second separators is two, and a ninth valve is arranged at an air inlet of each second separator; a tenth valve is arranged at the gas outlet of each second separator, and an eleventh valve is arranged at the discharge hole of each second separator; each second separator is provided with a second gas transmission hole capable of being switched between an opening state and a closing state, and the second gas transmission holes are used for introducing inert gas into the second separation chambers so that powder in the corresponding second separation chambers can enter the screener.

8. The closed-loop negative pressure powder circulation system of claim 6, wherein:

the closed-loop negative-pressure powder circulating system further comprises a powder post-processing part, an outlet of the powder post-processing part is communicated with a pipeline between an air inlet of the second separator and an air suction port of the negative pressure pump, a twelfth valve is arranged on a pipeline between a joint of the second separator and the powder post-processing part and the air suction port of the negative pressure pump, and a thirteenth valve is arranged on a pipeline between a joint of the second separator and the powder post-processing part; and an inlet of the powder post-processing part is communicated with an air outlet of the negative pressure pump, and a fourteenth valve is arranged on a pipeline for communicating the inlet of the powder post-processing part and the air outlet of the negative pressure pump.

9. The closed-loop negative pressure powder circulation system of claim 6, wherein:

the first separator, the first powder storage part, the powder feeding part, the second separator and the second powder storage part are all provided with material level meters.

10. A laser sintering apparatus, characterized in that the laser sintering apparatus comprises:

the closed loop negative pressure powder circulation system of any one of claims 1-9.

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