Polymer dry powder dosing and weighing device

Abstract

The utility model discloses a kind of polymer dry powder discharging metering weighing device, including powder storage tank, rotary feeder, weighing hopper, timer and PLC control system;Powder storage tank lower part is set to conical body, conical body bottom is set outlet, outlet connects rotary feeder, weighing hopper is set below rotary feeder, outlet is set on the weighing hopper bottom, and outlet is set outlet valve;Rotary feeder is driven by frequency conversion motor, frequency conversion motor is connected with PLC control system, and the rotational speed of frequency conversion motor is controlled by PLC control system to control discharging speed;Weighing hopper is installed on weight monitor to monitor the weight of weighing hopper in real time, and the monitored weight data is transmitted to PLC control system.The utility model's metering weighing device is accurate, can realize continuous uninterrupted weighing measurement, and polymer dry powder discharging speed can be adjusted in time according to needs, suitable for the scene that needs accurate measurement and accurate control polymer dry powder discharging speed.

Description

Technical Field

[0001] This utility model relates to the field of weighing and metering devices, and in particular to a weighing and metering device for discharging polymer dry powder. Background Technology

[0002] In many industries, the metering and addition of dry powder is crucial. This requires precisely adding the dry powder by weight or proportion to the required tank for stirring, mixing, or dissolving. In oilfield fracturing, large quantities of fracturing fluid with a certain viscosity are needed to reduce pipeline resistance or carry proppant into oil and gas-bearing formations, thereby breaking up the formation and increasing oil and gas recovery. This type of fracturing fluid is composed of water and polymer dry powder (such as polyacrylamide). Polyacrylamide and water quickly form a gel, making the proportion of dry powder added critical. Adding too little will not achieve the required viscosity, easily leading to increased pipeline friction and increased energy consumption of the fracturing pump. Adding too much not only wastes costs but also reduces pump efficiency due to excessively high viscosity.

[0003] Currently, the metering and addition of polymer dry powder in fracturing fluid preparation is done in a rather crude manner, mainly by adjusting the frequency of the screw conveyor to control the addition rate. However, different materials have different densities, and even with the same conveying frequency, the weight added will still vary, making it impossible to precisely control the material addition rate. Furthermore, due to the unique physicochemical properties of polymer dry powder, it exhibits strong adhesion when exposed to water or moisture. Over time, it gradually adheres to the screw blades, causing a decrease in the conveying speed of the screw conveyor at the same conveying frequency, thus increasing conveying errors. Summary of the Invention

[0004] To address the problem that current methods for controlling the metering of polymer dry powder during fracturing fluid preparation have significant errors and cannot accurately control the feeding speed of polymer dry powder, this invention provides a polymer dry powder feeding and metering weighing device.

[0005] The polymer dry powder feeding and weighing device provided by this utility model includes a powder storage tank, a rotary feeder, a weighing hopper, a timer, and a PLC control system.

[0006] The lower part of the powder storage tank is cone-shaped, with a discharge port at the bottom. The discharge port is connected to a rotary feeder, and a weighing hopper is located below the rotary feeder. The bottom of the weighing hopper also has a discharge port, and a discharge valve is installed on the discharge port. A vibrator A is installed on the outer wall of the powder storage tank to ensure that the polymer dry powder does not form an arching phenomenon inside the tank, thus preventing the polymer dry powder from clogging inside the tank and being unable to be discharged.

[0007] The rotary feeder consists of a housing, a rotating shaft, a scraper, and a variable frequency motor. The housing has an opening at the top as a feed inlet and a discharge outlet at the bottom. The feed inlet connects to the discharge outlet at the bottom of the powder storage tank, and the feed inlet and discharge outlet are positioned opposite each other. One end of the rotating shaft is horizontally inserted into the housing, and the scraper is mounted on the rotating shaft inside the housing. The other end of the rotating shaft is located outside the housing and connected to the variable frequency motor. The variable frequency motor drives the rotating shaft to rotate, which in turn drives the scraper to rotate, scraping out the polymer dry powder from the powder storage tank and discharging it through the discharge outlet at the bottom of the housing. The variable frequency motor is connected to a PLC control system, which controls the rotation speed of the variable frequency motor to control the feeding speed.

[0008] The weighing hopper is mounted on a weight monitor to read its weight in real time and transmits the monitored weight data to the PLC control system. Specifically, the weight monitor is an electronic scale, and the weighing hopper is suspended on the electronic scale, which monitors the weight of the hopper in real time. In another embodiment, channel steel is installed on both sides of the outer wall of the weighing hopper, and the weighing hopper is fixedly mounted on the electronic scale by the channel steel for weighing.

[0009] The weighing hopper is conical, with a sealed top and a feed inlet connected to the outlet of the powder storage tank. An outlet is located at the bottom of the cone. A vibrator B is installed on the outer wall of the weighing hopper. Vibrator B is a miniature vibrator to avoid interference from large amplitude on the weight monitor readings and to prevent bridging of the polymer powder as it falls into the weighing hopper.

[0010] Furthermore, the powder storage tank has a sealed structure, with a cylindrical upper part and a feed inlet at the top, and a conical lower part. The vibrator A is installed on the outer wall of the conical body, and the feed inlet is located at the top of the powder storage tank.

[0011] Preferably, the discharge valve is an electric ball valve, which is connected to a PLC control system. The PLC control system controls and adjusts its opening to control the discharge speed of the weighing hopper.

[0012] Compared with the prior art, the advantages of this utility model are: In the weighing device of this invention, the polymer dry powder in the powder storage tank enters the weighing hopper below after passing through the rotating feeder. The weight of the discharged polymer dry powder is accurately weighed and then discharged from the bottom of the weighing hopper, which can accurately control the addition rate of polymer dry powder.

[0013] In this invention, the weighing hopper is installed on an electronic scale that can display the weight in real time. It measures the weight of the weighing hopper rather than the weight of the entire powder storage tank, making measurement more convenient and accurate. The polymer dry powder enters from the top of the weighing hopper and exits from the bottom. The volume of the weighing hopper only needs to be 25-50L. The rotation speed of the rotary feeder and the opening of the discharge valve are controlled by a PLC control system to ensure dynamic stability of the weight in the weighing hopper.

[0014] Other advantages, objectives and features of this invention will be apparent in part from the description which follows, and in part from the understanding of those skilled in the art through study and practice of this invention. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the polymer dry powder feeding, metering, and weighing device provided by this utility model.

[0016] Figure 2 This is a schematic diagram of the rotary feeder.

[0017] Numbering on the map: 1-Powder storage tank, 2-Vibrator A, 3-Variable frequency motor, 4-PLC control system, 5-Scraper, 6-Weight monitor, 7-Discharge valve, 8-Discharge port, 9-Vibrator B, 10-Weighing hopper, 11-Rotary feeder, 12-Shell, 13-Rotating shaft, 14-Inlet of rotary feeder, 15-Outlet of rotary feeder, 16-Channel steel. Detailed Implementation

[0018] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0019] like Figure 1 As shown, the polymer dry powder feeding and weighing device provided by this utility model includes a powder storage tank 1, a rotary feeder 11, a weighing hopper 10, a PLC control system 4, and a timer (not shown).

[0020] The upper part of the powder storage tank 2 is cylindrical with a feed inlet at the top, and the lower part is conical with a discharge outlet at the bottom. The discharge outlet is connected to a rotary feeder 11, and a weighing hopper 10 is located below the rotary feeder 11. The bottom of the weighing hopper has a discharge outlet 8, and a discharge valve 7 (preferably an electric ball valve) is installed on the discharge outlet 8. One or more vibrators A 2 are installed on the outer wall of the powder storage tank 2 to ensure that the polymer dry powder does not form an arching phenomenon in the storage tank, thus preventing the polymer dry powder from clogging in the storage tank and being unable to be discharged.

[0021] like Figure 2As shown, the rotary feeder 11 consists of a housing 12, a rotating shaft 13, scrapers 5, and a variable frequency motor 3. The housing 12 is a vertically placed cylinder with openings at both ends. The top opening serves as the feed inlet 14, and the bottom opening serves as the discharge outlet 15. One end of the rotating shaft 13 is horizontally inserted into the housing 12 and passes through the housing, with the rotating shaft passing through the center of the housing's cross-section. At least two semi-circular scrapers 5 are installed on the rotating shaft inside the housing. The two scrapers are installed on opposite sides at the same position on the rotating shaft and spliced ​​together to form a circular scraper. The number of semi-circular scrapers is even (e.g., 2n) to ensure that all semi-circular scrapers are spliced ​​together to form n circular scrapers. In a preferred embodiment, there are four semi-circular scrapers, spliced ​​in pairs to form two circular scrapers. The two circular scrapers are perpendicular to each other, such that the included angle between adjacent semi-circular scrapers is 90 degrees, and the diameter of the formed circular scraper is equal to the inner diameter of the housing 12. Furthermore, a soft sealing ring is wrapped around the edge of the circular scraper to ensure that the dry powder in the powder storage tank cannot leak out from the gap between the scraper and the housing. The other end of the rotating shaft 13 is connected to a variable frequency motor 3 located outside the housing 12. The variable frequency motor 3 drives the rotating shaft 13 to rotate, which in turn drives the scraper 5 to rotate and scrape out the polymer dry powder in the powder storage tank 2 and discharge it through the outlet 15. The variable frequency motor 3 is connected to the PLC control system 4, and the feeding speed is controlled by controlling the rotation speed of the variable frequency motor 3 through the PLC control system 4.

[0022] The weighing hopper 10 is mounted on the weight monitor 6 to monitor the weight of the hopper in real time and transmits the monitored weight data to the PLC control system 4. In one specific embodiment, the weighing hopper 10 is conical, with a sealed top and a feed inlet connected to the outlet of the powder storage tank 2 via a flexible connection. An outlet is located at the bottom of the conical shape. A vibrator B 9 is installed on the outer wall of the weighing hopper. The vibrator B 9 is a miniature vibrator (e.g., a small attached vibrator RZD10-15C with a power of 15W, providing a small amplitude) to avoid interference from large amplitudes on the weight monitor values ​​and to prevent bridging of polymer powder falling into the weighing hopper. In this embodiment, the weight monitor 6 is an electronic scale. A channel steel 16 is installed on each opposite side of the outer wall of the weighing hopper 10, fixing the weighing hopper 10 to the electronic scale for weighing. The electronic scale monitors the weight of the weighing hopper 10 in real time. The volume of the weighing hopper can be 25-50L.

[0023] The weighing device of this invention controls the discharge speed of polymer dry powder from the storage tank by adjusting the rotation speed of the rotary feeder. After being discharged from the storage tank, the dry powder enters the weighing hopper, which can display the weight of the entire hopper in real time. The rate at which the weight increases is the rate at which the polymer dry powder enters the weighing hopper from the storage tank. A discharge valve is installed at the bottom of the weighing hopper to adjust the discharge speed of the polymer dry powder in the storage tank and the discharge speed in the weighing hopper to be consistent, so that the discharge speed of the polymer dry powder in the weighing hopper is kept constant at the required value, thereby achieving precise control of the discharge of polymer dry powder. By adjusting the rotation frequency of the rotary feeder and the opening of the discharge valve, the discharge speed of the polymer dry powder can be changed instantly.

[0024] The operation method for controlling the feeding speed of polymer dry powder (polyacrylamide dry powder) using the metering and weighing device of this utility model, taking a feeding speed of 10 kg / min as an example, is as follows: Add the polymer powder to the storage tank 1 and start the weighing hopper 10. At this time, the micro vibrator B 9 and the weight monitor 6 of the weighing hopper 10 start simultaneously. Initially, keep the electric ball valve 7 at the bottom of the weighing hopper closed. Adjust the frequency of the variable frequency motor 3 of the rotary feeder 11 to 10Hz to start the rotary feeder. The timing function of the weighing hopper starts immediately, and the timer starts counting. The polymer powder in the storage tank 1 is discharged into the weighing hopper 10 at a certain speed. The weight of the weighing hopper 10 increases uniformly. The PLC control system plots the weight increase curve of the weighing hopper 10 over time and calculates the slope of the curve in real time. This slope is the discharge speed of the polymer powder when discharged by the rotary feeder at a speed of 10Hz. If the slope of the curve does not reach 10 kg / min, the frequency of the variable frequency motor 3 will be automatically adjusted by the PLC control system until the slope of the weight increase of the weighing hopper 10 is uniformly maintained at the required value of 10 kg / min. Then, the electric ball valve 7 at the bottom of the weighing hopper 10 will be opened and the opening degree of the electric ball valve will be adjusted until the weight of the weighing hopper 10 remains constant. At this time, the discharge speed of the polymer dry powder from the weighing hopper 10 is equal to the discharge speed of the dry powder from the rotary feeder, both of which are 10 kg / min.

[0025] If, during subsequent use, it is necessary to increase the feeding speed of polymer dry powder based on the feeding speed of 10 kg / min, simply input the required value, for example, to increase it to 15 kg / min. The device will then automatically adjust (increase) the speed of the variable frequency motor 3 through the PLC control system, thereby increasing the feeding speed of the rotary feeder 11. When the slope of the calculated curve is 5 kg / min, the discharge speed of the polymer dry powder from the rotary feeder 11 will be 15 kg / min. Subsequently, the opening of the electric ball valve 7 at the bottom of the weighing hopper 10 will be increased until the weight of the weighing hopper 10 remains stable. At this point, the discharge speed of the polymer dry powder from the weighing hopper 10 will be equal to the discharge speed of the polymer dry powder from the rotary feeder, both being 15 kg / min. Conversely, if the feeding speed needs to be reduced from the 10 kg / min feeding speed, the rotation frequency of the variable frequency motor 3 is reduced, and the discharge speed of the rotary feeder 11 is reduced, so that the slope of the calculated curve is -3 kg / min. Then the discharge speed of the polymer dry powder from the rotary feeder 11 is 7 kg / min. Then the opening of the electric ball valve 7 below the weighing hopper 10 is reduced to keep the weight of the weighing hopper 10 stable. At this time, the discharge speed of the polymer dry powder from the weighing hopper 10 is equal to the discharge speed of the polymer dry powder from the rotary feeder 11, both of which are 7 kg / min.

[0026] In addition, the PLC control system of this utility model can also count the cumulative amount of polymer dry powder added, the addition time, the change curve of the addition speed, etc., and can accurately control and record the addition of polymer dry powder in the entire operation process.

[0027] The weighing method of this invention is simple to operate, accurate in measurement, and can achieve continuous and uninterrupted weighing. It can also adjust the feeding speed of dry powder in a timely manner as needed, making it very suitable for places that require precise measurement and adjustment of dry powder feeding.

[0028] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present utility model. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the scope of the present utility model shall still fall within the scope of the present utility model.

Claims

1. A polymer dry powder feeding and weighing device, characterized in that, It includes a powder storage tank, a rotary feeder, a weighing hopper, a timer, and a PLC control system; the lower part of the powder storage tank is set as a cone, the bottom of the cone is provided with a discharge port, the discharge port is connected to the rotary feeder, the weighing hopper is set below the rotary feeder, the bottom of the weighing hopper is provided with a discharge port, and a discharge valve is set on the discharge port. The rotary feeder is driven by a variable frequency motor, which is connected to a PLC control system. The feed speed is controlled by controlling the rotation speed of the variable frequency motor through the PLC control system. The weighing hopper is installed on a weight monitor to monitor the weight of the weighing hopper in real time and transmits the monitored weight data to the PLC control system. Vibrator A is installed on the outer wall of the powder storage tank.

2. The polymer dry powder feeding, metering, and weighing device as described in claim 1, characterized in that, The rotary feeder consists of a housing, a rotating shaft, a scraper, and a variable frequency motor. The top opening of the housing serves as the feed inlet, and the bottom opening is a discharge outlet. The feed inlet is connected to the discharge outlet at the bottom of the powder storage tank. One end of the rotating shaft is horizontally inserted into the housing, and the scraper is installed on the rotating shaft inside the housing. The other end of the rotating shaft is located outside the housing and is connected to the variable frequency motor. The variable frequency motor drives the rotating shaft to rotate, which in turn drives the scraper to rotate and scrape out the polymer dry powder from the powder storage tank.

3. The polymer dry powder feeding, metering, and weighing device as described in claim 1, characterized in that, The weighing hopper is conical, with a sealed top and a feed inlet. The feed inlet is flexibly connected to the discharge outlet of the powder storage tank, and the discharge outlet is located at the bottom of the cone.

4. The polymer dry powder feeding, metering, and weighing device as described in claim 3, characterized in that, The weight monitor is an electronic scale, and the weighing hopper is suspended on the electronic scale, which monitors the weight of the weighing hopper in real time.

5. The polymer dry powder feeding, metering, and weighing device as described in claim 4, characterized in that, Channel steel is installed on both sides of the outer wall of the weighing hopper, and the weighing hopper is fixedly installed on the electronic scale by the channel steel.

6. The polymer dry powder feeding, metering, and weighing device as described in claim 3, characterized in that, A vibrator B is installed on the outer wall of the weighing hopper.

7. The polymer dry powder feeding, metering, and weighing device as described in claim 1, characterized in that, The powder storage tank is a sealed structure with a cylindrical upper part, a feed inlet at the top, and a conical lower part. Vibrator A is installed on the outer wall of the conical body.

8. The polymer dry powder feeding, metering, and weighing device as described in claim 1, characterized in that, The discharge valve is an electric ball valve, and the opening degree of the electric ball valve is controlled by a PLC control system to control the discharge speed of the weighing hopper.

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