KR830001022B1 - Method for Mixing Particle Materials - Google Patents

Abstract

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Description

Method for Mixing Particle Materials

1 is a vertical sectional view of the hopper reservoir.

FIG. 2 is a partially enlarged view of the hopper reservoir of FIG. 1 detailing the interior of the lower distal region.

3 is a perspective view of the sealed hopper reservoir device body of FIGS.

4 is a schematic top cross-sectional view of the hopper reservoir device showing the internal interposition of the primary and secondary mixing tubes.

5 is a partial front view of the main mixing tube of the hopper reservoir showing the location of the holes drilled through the tube wall.

6 is an exploded schematic view of six auxiliary mixing tubes shown to show the relative positions of the holes drilled in the tube brick.

FIG. 7 is an exploded schematic view of three mixing tube support assemblies located at different heights in a hopper reservoir, as shown in FIG.

The present invention relates to a method and apparatus for mixing free flowing particulate matter contained in a hoppered bin. The operation can be one of a continuous method of simultaneously dropping and filling a substance into a predetermined volume that remains in a reservoir and a batch method of continuously dropping and filling one by one.

The mixing operation is performed by flowing the material out by gravity from several locations that are essentially uniformly distributed within the designated mixing zone of the reservoir.

The mixing zone may occupy all or only part of the total reservoir volume, depending on the application.

The present invention provides for the introduction of materials to be mixed in a reservoir: a downwardly extending main inlet with multiple inlet passages positioned and dimensioned to provide an unblocked or starved flow characteristic. (Main) through the tube wall through the tube wall to discharge some solid particulate matter by gravity: and also to the lower side where a number of material inlets are located and dimensioned in order to provide a blocked flow characteristic. Through the auxiliary auxiliary mixing tube device, it passes through the tube wall to discharge another part of the solid particle material: near the downstream end, it joins the various classes of substances in the enlarged area and the different classes of materials Join as all main and secondary mixing tube devices through which they pass as a mixed stream It provides a method of mixing solid particulate materials with high efficiency, consisting of maintaining unoccluded or depleted flow characteristics in the main mixing tube while maintaining the occluded flow characteristics in a plurality of auxiliary mixing tubes. .

The present invention will be described below with reference to the drawings.

As shown in the apparatus form of FIGS. 1 and 2 of the figure, the apparatus of the present invention comprises a main mixing tube 12 and a plurality of auxiliary mixing tubes connected into an enlarged portion 16 below the main tube 12. The hopper reservoir 10 which has 14 is comprised. The holes or passages 18a and 18b are drilled through the tube walls of the main and secondary mixing tubes 12 and 14, respectively. The mixing tubes are set up so that particulate matter flows into the tube and inside the tube the particulate material flows downwardly toward the outlet outlet in the lower region of the hopper reservoir or mixing vessel 10. The mass outflow rate is controlled by a valve device located at the downstream end of the mixing vessel.

The passages, or holes 18a, of the main tube are typically evenly distributed over the entire tube length, and for those particle materials to be mixed which are the fastest in size and with the smallest discharge rate, these holes are for example It is designed to provide only 75 percent emission rate. That is, the main mix tube 12 should not always be "depleted", i.e. occluded. Subsidiary materials required for the minimum discharge rate and higher discharge rates are the hopper flow of the material through the annular space 20 around the mixing skirt 22 and the passages or holes 18b of the auxiliary mixing tubes 14. And the flow of material through the auxiliary mixing tubes are combined.

The type of open or closed mixing vessel device is optionally employed within the scope of the present invention depending on the use in which the mixing vessel is used. Continuous operation will be advantageous for open mixing baths (the upper part being open to the atmosphere and capable of continuous filling), but closed continuous operating mixing baths may also be employed. It has been found that the closed device form is the best device form for all operations of the inventive mixing bath. Such top-sealed mixing vessels provide protective shielding to prevent foreign matter from entering the hopper mixing vessel reservoir as well as providing additional structural support for the internal mixing tube assembly.

The flow rate at which material enters the enlarged region 16 of the main tube 12 from the auxiliary tube 14 is self-adjusted so that at the discharge rate greater than the minimum discharge rate, the required incidental material is automatically supplied. . It has been found that "obstructed" auxiliary mixing tubes self-regulate the flow rate of material from the auxiliary tubes. This self-regulating effect is necessary to achieve the "obstructed-flow characteristics" in the auxiliary tubes of the mixing bath of the present invention. The inner cross-sectional area of the discharge area of the tube should be substantially equal to or greater than the cross-sectional area of the auxiliary mixing tube joined at the enlarged area and the junction. The self-regulating effect is provided by the value of the cross sectional area of the enlarged area and the ratio between the enlarged area and the area of the auxiliary mixing connection tube joined at the connection point satisfying a value of 1 or greater.

If the discharge rate is less than the combined maximum flow rate of the hopper and the main mix tube and the submix tubes, the subtube openings will be packed tightly until the subtube openings are almost completely occluded but the flowing region will form in the enlarged region.

This tightly packed region acts as a throttle for the subtube flow and prevents the tube from flowing at full speed. In this regard, it is said that the auxiliary tube shows a "closed flow characteristic". If the discharge rate is increased, the height of the tightly packed region will be lowered and the flow rate in the auxiliary tube will increase.

(The opposite occurs when the rate of discharge decreases).

When adopting a mixing vessel with an unoccluded main mixing tube and a number of occluded auxiliary mixing tubes interconnected with the outlets of the main tubes in the manner shown in FIG. 2 of the drawing, the height of the reservoir material is the height of all the auxiliary tubes. For manipulations placed over the measuring holes, each auxiliary tube will generally provide the same contribution to the entire material passed through all the auxiliary tubes.

Since auxiliary mixing tubes 14 are required to supply material over a wide range of flow rates, these tubes do not operate in a "depleted" state. If the mixing tube discharges material at a lower rate than is possible for a given number of material inflow measurement passages, or holes, the material that is tightly packed but the flowing material is lowered to the appropriate number by the presence of the tightly packed area. The holes will be closed and formed in the tube so that no material is supplied. Holes located above the height of the densely packed material allow for free supply of material.

As shown in the device form of the figure, each auxiliary mixing tube 14 has a plurality of passages distributed over only a portion of the vertical extension of the mixing zone. The upper feedstock holes of all the auxiliary tubes are intended to be able to combine them so that they are essentially uniformly distributed throughout the mixing zone regardless of the overall discharge rate. On the other hand, for the purpose of illustrating in connection with the description of the continuous method of operation, the measuring holes are shown only in certain parts of the mixing tube arrangement in the form of the mixing vessel device shown in FIG.

It should be understood that for both continuous or batch operation methods, such holes can extend substantially over the entire length of the auxiliary tubes.

Several auxiliary tubes (three or more) are used in the form of the device of the figure, whereby the cloth floating airflow from all the joined auxiliary tubes will be approximately evenly discharged from the mixing zone. The larger the number of subtubes, the more closely you approach the ideal case of a completely uniform discharge. However, because many holes in each auxiliary mixing tube will supply material even for the minimum discharge rate, relatively few tubes are required to match the performance of known gravity mixing systems with more mixing tubes. This fact naturally affects a significant reduction in costs.

A small amount of material flowing from around the mixing skirt 22 to the outlet outlet is best maintained at all times to prevent non-flow conditions in the lower region of the reservoir. As shown in FIG. 2, the bottom of the main mixing tube 12 consists of a conical section (mixing tube flare) 22, the bottom of which spans the cylindrical section 24 of the outlet hopper. This hopper is designed to provide a "mass flow" with an approximately constant mass flow rate through its cross section. The fluid entering the outlet hopper 24 will simultaneously flow and merge from the combined mixing tubes and the annular space 20 between the mixing tube flares and the inner hopper walls. It was found that the ratio of the two flow velocities was approximately equal to the ratio of the annular space area to that of the mixing tube flare. This supply of the lower section makes it clear that a certain portion (typically about 12%) of the total water flow represents the material discharged from the bottom of the hopper for all discharge rates.

The cross sectional area of the downstream stream hopper region is larger than the area of the enlarged portion 16.

During the batch operation of the discharge, the height of the material in the mixing bath will be reduced. It is necessary to equip the material measuring holes located above the height of the material, i.e., the passages, which are not activated and only operate when the material level is lowered. These holes are distributed on the auxiliary mixing tubes and distributed such that the material is drawn out of the region of the reservoir containing the mulled material approximately uniformly regardless of the height. During a continuous form of operation, a constant, predetermined volume of material will be in the mixing vessel and the holes that will be incapable of supplying material due to the tightly packed material in the auxiliary mixing tubes.

The mixing bath can also be employed as a purging operation as shown in FIG. 2 of the figure. This operation is required when flammable gases are likely to be released from particulate matter (eg low density polyethylene pellets). By keeping air flowing through the mixing bath these gases can be vented outwards to prevent the combustible mixture from accumulating in the hopper storage.

As shown in the figure, purging gas, such as air, is introduced through inlet pipe 26 and then flows through purge inlet line 28 to purge gas distributor 30 located in hopper reservoir 10. An additional purge gas line 32 is located in the mass outflow line 34, which is the top stream of the mass outflow sliding gate valve 36.

The purge gas valve 38 is located in the ancillary purge gas line 32 and is preferably kept open at initial charge only while the material outlet valve 36 is closed.

The whole mixing apparatus in the present invention is shown schematically in FIG. This type of device is a closed mixing bath with a top cover 40 and an inlet closure 42 of tubes located therein. The dust collector outlet device 44 is also secured to the top cover 40 as at the resin inlet through the resin inlet tube 46. The main mixing tube 12 and six auxiliary mixing tubes 14 are also located inside the mixing vessel body 10. All mixing tubes are end fixed in an enlarged portion 22 at the bottom of the mixing vessel. The purge air entering through the inlet line 48 passes to the lower portion of the mixing tank outlet at the same time as the purge air disperser 50 in the mixing tank body 10. As shown in FIG. 3, the outflow slide valve 36 and the outflow mixing tank resin line 52 are provided.

As shown in FIG. 4 of the figure, six auxiliary mixing tubes 14 are located around the main mixing tube 12 in the mixing vessel body 10.

5 shows the main mixing tube 12 and shows the arrangement of the main mixing tube holes 18a positioned successively at 90 ° to each other along the length of the main mixing tube.

An exploded view showing six submixing tubes 14 is shown in FIG. 6, with a good relative positional arrangement with respect to the submixing tube holes 18b.

The mixing tank of the device type shown in the drawing is a type of throwing device, which is represented by (54a), (54b) and (54c) in Figs. Same as the three stage assembly.

As shown in more detail in FIG. 7 the heights 1,2 and 3 show these assemblies in the outer mixing vessel wall 10. Height 1 and height 3 are substantially the same, with height 2 providing a misaligned arrangement of brace pairs for heights 1 and 3. The brace assembly at each height seals the main mixing tube 12 and the auxiliary mixing tube 14 by separate support seals in each of the outer sleeve devices 60 and 62. These external sleeve devices are then connected via the support device 64 to either the sleeve devices or to the mixing basin brick as seen at the three heights of FIG.

The method and apparatus of the present invention may be employed for mixing any solid particle materials. They are particularly suitable for mixing materials of thermoplastics (such as low density polyethylene, high density polyethylene, etc.). Mixing baths of this type show high mixing efficiency and high processing capacity (more than 40,000 pounds per hour) in handling polyethylene particle materials.

In the practice of the present invention, the mixing device is designed to provide an adjustable mass transfer rate (processing capacity) of particulate polyethylene material between 15,000 and 40,000 pounds per hour.

This mixing device is made in the general design as shown in the device form of the figure. Such a mixing tank can handle a wide range of particulate matter such as low density and high density particle polyethylene resin. The total area of the mixing vessel was 13,000 ft ³ , which provided a mixing volume of 7,000 ft ³ (predetermined minimum volume of material maintained during continuous mixing of forms). The outer reservoir surface of the mixing vessel was made of 5052-H32 aluminum alloy with an inner diameter of 16ft, a columnar section height of approximately 60ft and an angle of bottom hopper 60 ° from horizontal.

The outlet hopper insert below the main hopper is made of a similar aluminum alloy and has a 39-inch inner diameter, a 30-inch columnar section and a hopper angle 70 ° from the horizontal. The main mix tube consisted of 8 in 6061-T6 aluminum alloy pipes long enough to extend to the top of the reservoir. Thirty-four main mixing tube holes were installed, each with a diameter of 1-3 / 8 in and evenly distributed throughout the mixing area. The holes were drilled at right angles to the tube center line and finished. Two holes were located 180 ° apart from each height.

These pairs of holes were previously rotated by 90 ° to the pairs of holes at height. The auxiliary mixing tubes were six in number and each consisted of 6061-T6 aluminum alloy pipes of 6 inch diameter and of sufficient length to extend to the top of the reservoir. Each auxiliary mixing tube had 16 to 48 holes of 1-3 / 8 in diameter, located relatively in a hole arrangement similar to that employed for the main mixing tube. The purge air flow rate of 250 SCFM was maintained at all times. The minimum discharge rate for mixing tank operation employing high density polyethylene materials is 15,000 pounds per hour, where 10,540 pounds per hour flow through the main tube and 2435 pounds per hour flow through the combined auxiliary tubes and 2025 pounds per hour It flows through the annular space 20 between the flare and the hopper reservoir wall.

The maximum discharge rate is 40,000 pounds per hour, where the calculated 10,540 pounds per hour flow through the main tube, 24060 pounds per hour through the associated auxiliary tubes, and 5400 pounds per hour flow through the torus.

A toric space flow always has a fixed percentage of total outflow, but a constant amount of material flows through the main mix tube and a self-adjusted outflow flows to provide the required additional material to the collection of auxiliary mix tubes.

In this device, four 1 1/2 inch diameter holes were placed near the top of all seven union tubes, below the mixing vessel lid and above the maximum resin height to provide even pressure in the tubes.

Of course, for those skilled in solids material mixing techniques, the parameters of the basic elements of the inventive device will yield the best results for a variety of materials, including the volume to be processed and the best flow rates in terms of mixing operations. It is well understood that it should be set up.

Claims (1)

As described above in the text, the materials to be mixed are introduced into the reservoir: a plurality of inlet passages positioned and dimensioned through the wall of the main tube to provide flow characteristics that are not blocked or depleted. And discharging a portion of the solid particle material by gravity through the main mixing tube devices extending into the chamber: a plurality of material inlet passages, each of which is positioned and dimensioned, to provide a closed flow characteristic, located through the wall of the auxiliary mixing tube. Gravity discharges the solid particulate material to another part by gravity through a number of sub-mixed tube devices connected downwards: merging the different classes of materials in an enlarged area near the downstream end and the different classes of materials being the main mix. Mixed strips joined with tube and auxiliary mixing tube devices And part of the solid particulate material is transported to the downstream region by gravity as an external toroidal stream between the enlarged zone and the reservoir wall and further mixed with the mixed stream: an unoccluded or depleted flow in the main mixing tube. A method of mixing a high proportion of solid particulate materials consisting of steps that maintain properties while maintaining flow characteristics that are occluded in many auxiliary mixing tube devices.

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