CN109228327A - Liquid precise metering device and 3DP printing device - Google Patents

Abstract

The present invention relates to a 3DP printing device including a liquid precision metering device. The liquid precision metering device includes: an injection mechanism, a storage tank, a reversing valve and a stirrer; the injection mechanism includes a syringe, a piston, a piston connecting rod, a screw rod and a driving part, the piston and the piston connecting rod are movably accommodated in the inner cavity of the syringe, one end of the piston connecting rod is connected to the piston, the screw rod is connected to the other end of the piston connecting rod, and the driving member is drivingly connected to the screw rod The storage tank has a liquid inlet and a liquid outlet pipe, the liquid inlet is used to transport the liquid to be metered, the reversing valve communicates the liquid outlet pipe and the syringe, and the agitator communicates with the exchange to the valve. The liquid precision metering device used in 3DP printing equipment is suitable for precise metering of small volume and corrosive liquids to improve the stability of equipment operation and reduce equipment costs.

Description

Liquid precision metering device and 3DP printing equipment

technical field

The invention relates to the technical field of measuring instruments, in particular to a liquid precision measuring device and a 3DP printing device.

Background technique

3DP (Three-Dimensional Printing, powder material forming technology) is a kind of 3D printing technology. Binder is an indispensable material in 3DP printing technology, and because many of these binders are highly corrosive and acidic, they will cause serious corrosion to equipment and measuring instruments during the actual printing process, affecting printing. process. In addition, the 3DP printing process has very strict requirements on the ratio of powder and binder, and requires high accuracy. The accuracy of the ratio directly determines the curing time, strength and other parameters of the product. Generally, the proportion of binder is very small. Usually the addition amount is only about tens of grams. When the solid and liquid are mixed, the addition amount of the binder needs to be accurately measured. However, it is difficult for the prior art metering device to achieve precise metering for highly corrosive, small-dose liquids. Specifically, the measurement device in the prior art usually measures the liquid by means of a flowmeter, a float-type liquid level gauge, an ultrasonic liquid level gauge, etc. The above methods are desirable for accurate measurement of a large flow of neutral liquid, but for There are some uncontrollable factors in the measurement of small-volume liquids, especially those with corrosive liquids, and it is difficult to be practically applied. For example, flowmeters generally have measurement blind spots, which cannot be identified when the flow rate is very small, so it will cause measurement errors, and the highly corrosive liquid will cause damage to the measuring electrodes of the flowmeter and other devices, so it will seriously affect Final measurement result.

SUMMARY OF THE INVENTION

Based on this, it is necessary to provide a suitable solution for the measurement devices in the prior art, which have measurement errors in the measurement of small volumes of liquids and corrosive liquids. It is a liquid precision metering device and 3DP printing equipment that can accurately measure small volume and corrosive liquids to improve the stability of equipment operation and reduce equipment costs.

A liquid precision metering device includes: an injection mechanism, a storage tank, a reversing valve and a stirrer; the injection mechanism includes a syringe, a piston, a piston connecting rod, a screw rod and a driving part, and the piston and the piston connecting rod are both is movably accommodated in the inner cavity of the syringe, one end of the piston connecting rod is connected to the piston, the screw rod is connected to the other end of the piston connecting rod, and the driving member is drivingly connected to the screw rod; The storage tank has a liquid inlet and a liquid outlet, the liquid inlet is used for conveying the liquid to be measured, the reversing valve is connected with the liquid outlet pipe and the syringe, and the agitator is connected with the reversing valve.

In one embodiment, the liquid precision metering device further includes a buffer tank, the liquid inlet of the buffer tank is connected to the storage tank, and the liquid outlet of the buffer tank is connected to the liquid inlet of the syringe .

In one embodiment, a liquid material pump is provided on the connecting pipe between the storage tank and the buffer tank.

In one embodiment, the liquid material pump is a vacuum diaphragm pump.

In one of the embodiments, the buffer tank is provided with a liquid level detection sensor, and the liquid level detection sensor is interlocked with the liquid material pump.

In one of the embodiments, the storage tank is provided with the liquid level detection sensor.

In one of the embodiments, both the top of the storage tank and the top of the buffer tank are provided with exhaust parts.

In one of the embodiments, the reversing valve includes a multi-channel valve or a three-way reversing valve.

In one embodiment, the driving member includes any one of a stepping motor, a servo motor, a pneumatic servo and a hydraulic device.

A 3DP printing device includes a liquid precision metering device.

The above-mentioned 3DP printing equipment including a liquid precision metering device, by setting the injection mechanism including a syringe, a piston, a piston connecting rod, a screw rod and a driving member, the angular motion of the driving member is converted into the linear motion of the screw rod, and drives the piston rod and the connecting rod. The driving piston moves along the inner cavity of the syringe, so that the feeding amount of the syringe can be controlled by the pulse number of the driving element, so as to realize the precise control of the liquid flow rate in the inner cavity of the syringe; and by setting the reversing valve connecting the agitator and the syringe , to achieve precise delivery of the liquid in the connected storage tank to the agitator through the injection mechanism to supply the 3DP printing equipment for use.

Description of drawings

FIG. 1 is a schematic structural diagram of a liquid precision metering device according to an embodiment.

Detailed ways

In order to facilitate understanding of the present invention, the present invention will be described more fully hereinafter with reference to the related drawings. The preferred embodiments of the invention are shown in the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that a thorough and complete understanding of the present disclosure is provided.

It should be noted that when an element is referred to as being "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical", "horizontal", "left", "right", "top", "bottom", "bottom", "top" and similar expressions used herein are for Not meant to be the only implementation.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

In one embodiment, a liquid precision metering device includes: an injection mechanism, a storage tank, a reversing valve and a stirrer; the injection mechanism includes a syringe, a piston, a piston connecting rod, and a screw rod. and a driving part, the piston and the piston connecting rod are both movably accommodated in the inner cavity of the syringe, one end of the piston connecting rod is connected to the piston, and the screw rod is connected to the end of the piston connecting rod. At the other end, the driving member is drivingly connected to the screw rod; the storage tank has a liquid inlet and a liquid outlet pipe, the liquid inlet is used to transport the liquid to be metered, and the reversing valve is connected to the liquid outlet pipe The reversing valve is communicated with the syringe and the agitator.

In one embodiment, a 3DP printing device includes a liquid precision metering device, the liquid precision metering device includes: an injection mechanism, a storage tank, a reversing valve, and a stirrer; the injection mechanism includes a syringe, a piston, a piston A connecting rod, a screw rod and a driving member, the piston and the piston connecting rod are movably accommodated in the inner cavity of the syringe, one end of the piston connecting rod is connected to the piston, and the screw rod is connected to the The other end of the piston connecting rod, the driving member is drivingly connected to the screw rod; the storage tank has a liquid inlet and a liquid outlet pipe, the liquid inlet is used for conveying the liquid to be measured, and the reversing valve communicates with The liquid outlet pipe is communicated with the syringe and the agitator in communication with the reversing valve.

The above-mentioned 3DP printing equipment including a liquid precision metering device, by setting the injection mechanism including a syringe, a piston, a piston connecting rod, a screw rod and a driving member, the angular motion of the driving member is converted into the linear motion of the screw rod, and drives the piston rod and the connecting rod. The driving piston moves along the inner cavity of the syringe, so that the feeding amount of the syringe can be controlled by the pulse number of the driving element, so as to realize the precise control of the liquid flow rate in the inner cavity of the syringe; and by setting the reversing valve connecting the agitator and the syringe , to achieve precise delivery of the liquid in the connected storage tank to the agitator through the injection mechanism to supply the 3DP printing equipment for use.

The following describes the precise liquid metering device of the 3DP printing device with reference to specific embodiments, so as to further understand the inventive concept of the liquid precise metering device. In one embodiment, please refer to FIG. 1 , a liquid precision metering device 10 includes: an injection mechanism 100 , a storage tank 200 , a reversing valve 300 and an agitator 400 , the reversing valve 300 communicates with the injection mechanism 100 , the storage tank 200 and the agitator 400 . The injection mechanism 100 is used to precisely control the flow rate of the metered liquid, the agitator 400 is used to receive the liquid accurately metered by the injection mechanism 100 , and the storage tank 200 is used to store the liquid to be measured input from an external container. The liquid in communication with the storage tank 200 is metered by the injection mechanism 100 , so that the precisely metered liquid is discharged to the mixer 400 through the reversing valve 300 for use by the 3DP printing device.

Please continue to refer to FIG. 1 , the injection mechanism 100 includes a syringe 110 , a piston 120 , a piston connecting rod 130 , a screw rod 140 and a driving member 150 . Both the piston 120 and the piston connecting rod 130 are movably accommodated in the syringe In the inner cavity of 110 , one end of the piston rod 130 is connected to the piston 120 , the screw rod 140 is connected to the other end of the piston rod 130 , and the driving member 150 is drivingly connected to the screw rod 140 . In one embodiment, the driving member 150 includes any one of a stepping motor, a servo motor, a pneumatic servo and a hydraulic device. That is, the driving member 150 may be any type of driving mechanism, including any one of electromechanical, pneumatic and hydraulic driving. Specifically, the syringe 110 is a container with a regular cross-section, for example, the cross-section of the syringe 110 is circular. The piston 120 can move freely in the inner cavity of the syringe 110 and has good sealing performance. The movement of the piston 120 is controlled by the driving member 150, for example, the quantity, frequency and direction of the pulses generated by the controller of the stepping motor are used to control the liquid injection volume and the feeding speed in the storage tank 200 and direction of movement.

Specifically, the realization principle of the precise control of the liquid metering in the storage tank 200 by the injection mechanism 100 is that the injection amount is proportional to the number of pulses for controlling the stepping motor, and accordingly, the pulse number of the stepping motor can be controlled by To achieve precise control of liquid flow. Generally speaking, after the step angle of the stepper motor is subdivided, the precision of a single pulse corresponding to the rotation angle of the motor is very high, and the driving screw can reach the micron-level feed, so the accurate measurement of small liquid flow can be realized. Specifically, the rotation (angular displacement) of the stepping motor drives the lead screw 140 to rotate, converts the angular displacement of the motor into linear displacement, and drives the piston 120 to perform linear motion (linear displacement). The accuracy of the injection volume of the syringe 110 depends on the positioning accuracy of the movement of the piston 120, and the stroke of the piston 120 is determined by the number of revolutions of the stepping motor, which is determined by the number of driving pulses generated by the controller. Control the corresponding number of turns of its rotation, that is, every time the stepper motor receives a pulse, it will rotate a certain angle accordingly. Among them, it should be noted that the meaning of the subdivision of the step angle of the stepping motor is: the larger the subdivision number, the smaller the rotation angle of the motor receiving a pulse, that is, the higher the control precision. After subdivision, the more accurate the stroke positioning of the piston, the more accurate the corresponding measurement.

Please continue to refer to FIG. 1 , the storage tank 200 has a liquid inlet 210 and a liquid outlet pipe 220 , the liquid inlet 210 is used for conveying the liquid to be measured, and the reversing valve 300 communicates the liquid outlet pipe 220 with the liquid outlet pipe 220 . The syringe 110 is connected to the agitator 400 and the reversing valve 300 is connected. That is, the reversing valve 300 is installed at the outlet of the syringe 110 , wherein the reversing valve 300 can control the flow direction of the liquid (liquid inlet or outlet). In one embodiment, the reversing valve 300 includes a multi-channel valve or a three-way reversing valve. That is, the multi-channel valve can replace the three-way reversing valve to realize multi-channel metering. Among them, the commonly used multi-channel valves are: T-type valve, Y-type valve, 4-channel valve, 8-channel valve, etc. Specifically, in the actual measurement process, when the piston rod 130 is pulled by an external force and the reversing valve 300 is switched to the liquid feeding direction, the liquid in the storage tank 200 is sucked into the inner cavity of the syringe 110 ; When the piston rod 130 is pushed by an external force, and the reversing valve 300 is switched to the liquid discharging direction, the liquid in the syringe 110 is discharged to the agitator 400 . That is to say, the suction and discharge of the liquid material are switched by the reversing valve 300. Here, one-way valves can also be installed at the liquid inlet and the liquid outlet to realize the switching of the liquid path, and its function is the same. . The liquid material is discharged through the reversing valve 300 and then flows into the agitator 150. The agitator 150 has a stirring motor, and is mixed with the solid powder under the rotation of the stirring motor to realize the precise ratio of solid and liquid.

According to the above embodiment, the metering process of the liquid precision metering device 10 is divided into two steps. The first step is the liquid adding phase: after the system receives the command, the program controls the driving member 150 (for example, the stepping motor rotates forward) , the piston 120 is connected with the screw rod 140 through the piston connecting rod 130. When the motor rotates forward, the piston 120 is pulled out, and the liquid material is sucked into the syringe 110 under the action of negative pressure. When the piston 120 moves to the set position, the driving member 150 (for example, the stepping motor stops working) stops working, the inner cavity of the syringe 110 is filled with liquid material, and the liquid addition is completed; the second step is to discharge Liquid stage: the driving member 150 (for example, the stepping motor is reversed) pushes out the piston, and the liquid is discharged from the syringe 110. When the injection volume reaches the set value of the added amount, the driving member 150 (for example: The stepper motor stops working) stops working, and the liquid discharge ends.

In the above-mentioned 3DP printing device including the liquid precision metering device, by setting the injection mechanism including the syringe 110 , the piston 120 , the piston connecting rod 130 , the screw rod 140 and the driving member 150 , the angular motion of the driving member 150 is converted into a straight line of the screw rod 140 move, and drive the piston rod 130 to drive the piston 120 to move along the inner cavity of the syringe 110, so that the feeding amount of the syringe 110 can be controlled by the number of pulses of the driving member 150, so as to realize the precise control of the liquid flow in the inner cavity of the syringe 110 ; And by setting the reversing valve 300 that communicates between the agitator 400 and the syringe 110, the liquid in the communication storage tank 200 is accurately delivered to the agitator 400 through the injection mechanism 100 to supply the 3DP printing device for use.

In order to prevent the syringe 110 from being mixed with air when sucking the liquid material, in one embodiment, the liquid precision metering device further includes a buffer tank 500 , and the liquid inlet of the buffer tank 500 is connected to the storage tank 200 , the liquid outlet of the buffer tank 500 communicates with the liquid inlet of the syringe 110 . In one embodiment, the installation height of the buffer tank 500 is greater than the installation height of the reversing valve 300 . In this way, the liquid material in the buffer tank fills and seals the pipeline under the action of gravity, which ensures that the gas will not enter the inner cavity of the syringe 110 and cause errors when the syringe 110 sucks the liquid material. That is, the buffer tank 500 is added to the front end of the liquid inlet of the syringe 110 to ensure that the liquid inlet of the syringe 110 is sealed with liquid, which plays the role of isolating air, and effectively ensures that the syringe 110 does not Errors will occur due to air intake.

In order to quickly replenish the liquid material in the buffer tank when the liquid level reaches the lower limit, in one embodiment, a liquid material pump 600 is provided on the connecting pipe between the storage tank 200 and the buffer tank 500 . In one embodiment, the liquid material pump 600 is a vacuum diaphragm pump. That is, the liquid in the storage tank 200 is transferred to the buffer tank 500 through the vacuum diaphragm pump. Further, the buffer tank 500 is installed with a liquid level detection sensor 700 , and the liquid level detection sensor 700 is interlocked with the liquid material pump 600 . In this way, by installing a sensor for detecting the liquid level in the buffer tank 500, the sensor signal is interlocked with the liquid material pump 600, and when the liquid level in the buffer tank 500 reaches the lower limit, the liquid material pump 600 automatically starts To replenish the liquid material, when the liquid level of the buffer tank 500 reaches the upper limit, the liquid material pump 600 stops working, so that the buffer tank 500 is always filled with liquid material.

In order to facilitate timely replenishment of the liquid level of the storage tank, in one embodiment, the storage tank 200 is provided with the liquid level detection sensor 700 . For example, the liquid level detection sensor 700 is divided into high, medium and low liquid level sensors. In this way, the liquid level in the storage tank 200 can be detected immediately, and when the liquid level reaches the lower limit, the system alarms or automatically replenishes the liquid material.

In order to ensure that the internal and external pressures of the storage tank 200 and the buffer tank 500 are balanced, in one embodiment, an exhaust member 800 is installed on the top of the storage tank 200 and the top of the buffer tank 500 . For example, the exhaust member 800 is an exhaust valve. In this way, by installing the exhaust member on the top of the storage tank 200 and the top of the buffer tank 500, the gas can be discharged or sucked in in time when the liquid level in the tank changes, so as to ensure the pressure balance inside and outside the tank , so that the liquid can flow freely.

It should be noted that the liquid precision metering device applied to the 3DP printing equipment can realize the function of precise quantitative control of highly corrosive liquids. In addition to the main medium and binder, the humectants, quick-drying agents, lubricants, coagulants, flow enhancers, pH adjusters and other additives (such as dyes, defoaming agents) added during the printing process, etc. All materials can also be precisely metered by the liquid precise metering device, that is, the liquid precise metering device in any of the above embodiments can meter all the above liquid materials.

The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity, all possible combinations of the technical features in the above-described embodiments are not described. However, as long as there is no contradiction between the combinations of these technical features, All should be regarded as the scope described in this specification.

The above-mentioned embodiments only represent several embodiments of the present invention, and the descriptions thereof are more specific and detailed, but should not be construed as a limitation on the scope of the invention patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can also be made, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims (10)

1. a liquid precision metering device, it is characterized in that, described liquid precision metering device comprises: injection mechanism, storage tank, reversing valve and agitator; The injection mechanism includes a syringe, a piston, a piston connecting rod, a screw rod and a driving member. Both the piston and the piston connecting rod are movably accommodated in the inner cavity of the syringe, and one end of the piston connecting rod is connected to the piston, the screw rod is connected to the other end of the piston connecting rod, and the driving member is drivingly connected to the screw rod; The storage tank has a liquid inlet and a liquid outlet, the liquid inlet is used for conveying the liquid to be measured, the reversing valve is connected with the liquid outlet pipe and the syringe, and the agitator is connected with the reversing valve. 2 . The liquid precision metering device according to claim 1 , wherein the liquid precision metering device further comprises a buffer tank, the liquid inlet of the buffer tank is communicated with the storage tank, and the outlet of the buffer tank is connected to the storage tank. 3 . The liquid port communicates with the liquid inlet of the syringe. 3 . The liquid precision metering device according to claim 2 , wherein a liquid material pump is provided on the connecting pipe between the storage tank and the buffer tank. 4 . 4 . The liquid precision metering device according to claim 3 , wherein the liquid material pump is a vacuum diaphragm pump. 5 . 5 . The liquid precision metering device according to claim 3 , wherein a liquid level detection sensor is installed in the buffer tank, and the liquid level detection sensor is interlocked with the liquid material pump. 6 . 6 . The liquid precision metering device according to claim 5 , wherein the storage tank is provided with the liquid level detection sensor. 7 . 7 . The liquid precision metering device according to claim 2 , wherein an exhaust member is installed on the top of the storage tank and the top of the buffer tank. 8 . 8 . The liquid precision metering device according to claim 1 , wherein the reversing valve comprises a multi-channel valve or a three-way reversing valve. 9 . 9 . The liquid precision metering device according to claim 1 , wherein the driving element comprises any one of a stepping motor, a servo motor, a pneumatic servo and a hydraulic device. 10 . 10. A 3DP printing device, characterized in that it comprises the liquid precision metering device according to any one of claims 1 to 9.