JP5513699B1 - Thermal insulation cover body and injection molding machine - Google Patents

Abstract

[PROBLEMS] To simultaneously reduce the cost of a heat insulating cover body, simplify the work of assembling the heat insulating cover body to a heating cylinder, and greatly reduce power consumption.
A heat insulating cover body 30 is formed by molding a plurality of split cylinders 31 obtained by dividing a cylindrical body having a diameter larger than that of a heating cylinder 20 along an axial direction, and a material having excellent heat insulation properties. A plurality of spacers 40 and 45 provided on the inner peripheral surface of 31 along the circumferential direction and holding means for holding the plurality of split cylinders in a cylindrical shape are provided, and the plurality of split cylinders 31 are interposed via the spacers 40 and 45. Are separated from the heating cylinder 20, and a plurality of annular shapes surrounding each heater 23 between the plurality of split cylinders 31 and the peripheral surface of the heating cylinder 20 via spacers 40 and 45 that are in contact with the outer peripheral surface of the heating cylinder 20. A space 33 was defined.
[Selection] Figure 1

Description

  The present invention relates to a heat insulating cover body of an injection molding machine such as a plastic injection molding machine and an injection molding machine.

  The injection part of the injection molding machine includes a heating cylinder, a screw accommodated in the heating cylinder, a hopper for supplying a raw material resin (pellet) into the heating cylinder, and a plurality of heaters (band heaters) arranged around the heating cylinder. Etc.

The conventional injection molding machine consumes a large amount of electric power to rapidly heat the raw material resin in the heating cylinder with a plurality of heaters.
In order to effectively use the heating energy of the heater and to prevent a contact accident with the heater, the periphery of the heating cylinder is covered with various covers.

Patent Document 1 discloses a cover including a flexible heat insulating layer that is wound around the outer periphery of a heating cylinder and a cover that covers the heat insulating layer.
Patent Document 2 discloses a cover made of a metal cylindrical cover arranged inside and outside double and a heat insulating material inserted or foamed between the peripheral surfaces of the double cylindrical cover.
Patent Document 3 discloses a cover comprising a stainless steel inner and outer double cylinder wound around the outer periphery of a heating cylinder and an air layer formed between the inner and outer double cylinders.

Japanese Utility Model Publication No. 61-95511 Japanese Utility Model Publication No. 63-10263 JP 2004-291545 A

The conventional cover has the following problems.
<1> The cover described in Patent Document 1 does not disclose the specific structure and material of the flexible heat insulating layer and the cover.
<2> The cover described in Patent Document 2 or 3 has a problem that the structure is complicated and the cost is high, and that a lot of time and labor are required for production and assembly.
<3> In the cover described in Patent Document 3, the heat dissipated from the heater is stored in a stainless steel cylinder, and the absorbed heat becomes a heat source and further transferred to the outside, resulting in energy loss. There are many.
<4> Each heater has a lead wire, and when assembling the conventional cover to the heating cylinder, it is necessary to draw out a plurality of lead wires to the outside of the cover.
Conventionally, a plurality of openings having a side of 15 to 20 cm square are formed in a part of the cover in accordance with the wiring position of the lead wires, and a plurality of lead wires are drawn to the outside through these openings.
Since the opening opened in the cover is several tens of times larger than the lead wire, the heat of each heater is dissipated into the atmosphere through the opening, resulting in variations in the heat retention performance of the cover.
<5> As described above, the conventional cover has the problem of cost, the problem of assembling workability to the heating cylinder, and the problem of the processing of the lead wire drawing portion.
<6> Although the conventional cover can be expected to have a certain heat retention effect, it has not yet been able to significantly reduce the power consumption by the heater.
As the size of the injection molding machine increases, the power consumption by the heater increases. Therefore, the economic loss is large, and a proposal for an improved technique is desired.
<7> Although various covers have been proposed for small injection molding machines, the heating temperature of the heater for medium and large injection molding machines that mold medium and large resin products such as car bumpers and dashboards Since it becomes high, there are many problems to be solved, and a proposal of a suitable heat insulation technology that satisfies the plurality of problems shown in <5> has not been made yet.

The present invention has been made in view of the above points, and an object thereof is to provide at least one heat insulation cover body and an injection molding machine.
<1> A reduction in the cost of the heat insulating cover body, simplification of the work of assembling the heat insulating cover body to the heating cylinder, and a significant reduction in power consumption can be achieved at the same time.
<2> Appropriate for keeping the temperature of the injection part of medium- and large-sized injection molding machines.
<3> Maintenance is not required and durability is excellent.

The present invention is a heat insulation cover body that covers an injection part of an injection molding machine including a heating cylinder and a plurality of heaters wound around the outer periphery of the heating cylinder at a predetermined interval, and has a larger diameter than the heating cylinder. A plurality of split cylinders obtained by dividing the cylindrical body along the axial direction, a material having excellent heat insulation properties, a plurality of spacers provided along the circumferential direction on the inner peripheral surface of the split cylinder, Holding means for holding the plurality of split cylinders in a cylindrical shape, and the plurality of split cylinders are separated from the heating cylinder via the spacers, and a plurality are provided via the spacers that are in contact with the outer peripheral surface of the heating cylinder. A plurality of annular spaces surrounding each heater are defined between the peripheral cylinder and the peripheral surface of the heating cylinder.
In another embodiment of the present invention, a notch groove into which a lead wire extending from the heater can be inserted is formed on a side end surface of the plurality of split cylinders, and the lead is led through a lead hole formed by abutting the pair of notch grooves. The wire can be pulled out of the heat insulating cover body.
In another embodiment of the present invention, a heat retaining mat may be provided on the inner peripheral surface of the split tube.
In another embodiment of the present invention, the plurality of spacers include an intermediate spacer provided on the inner peripheral surface of each split tube and terminal spacers provided on both ends of the inner peripheral surface of each split tube, It is a molded article containing potassium silicate.
In another embodiment of the present invention, the split tube is a molded product of ceramic fiber.
In another embodiment of the present invention, the split tube is formed of a rockwall housing.
Further, the present invention is an injection molding machine comprising a heating cylinder having a nozzle at the tip and a plurality of heaters wound around the outer periphery of the heating cylinder at a predetermined interval, wherein any one of the above-mentioned heat insulation machines A cover body is mounted on the heating cylinder, the plurality of split cylinders are separated from the heating cylinder via the spacers, and the plurality of split cylinders and the heating cylinders are interposed via the spacers that are in contact with the outer peripheral surface of the heating cylinder. A plurality of annular spaces surrounding each heater are defined between the peripheral surfaces.

The present invention has at least one of the following effects by having the above configuration.
<1> By using a heat insulating cover body with a simple structure including a plurality of split cylinders and a plurality of spacers, the cost of the heat insulating cover body is reduced and the work of assembling the heat insulating cover body to the heating cylinder is simplified. And a significant reduction in power consumption by the heater can be achieved at the same time.
In particular, it is possible to increase the average power consumption reduction rate to more than 20% by using a low-cost heat insulating cover body, which is difficult to achieve with a conventional cover.
<2> Not only can it be applied to small injection molding machines, it can also be applied to medium and large injection molding machines.
In particular, the effect of reducing power consumption appears more markedly as the injection molding machine becomes larger, and the economic effect is greater.
<3> Since the heat insulating cover body is a molded product, maintenance of the heat insulating cover body is unnecessary and excellent in durability.
<4> Since the lead wire can be pulled out to the outside of the heat insulating cover body through a notch groove (drawer hole) formed in the necessary minimum size in the split cylinder, the airtightness of each annular space formed in the heat insulating cover body The heat insulation performance and heat insulation performance by each annular space are improved.
<5> The thermal insulation performance can be optimally adjusted for each annular chamber by selecting the thickness of the spacer or split cylinder for each annular chamber, or selecting the volume of the annular chamber.

Partial sectional view of an injection part of an injection molding machine according to the present invention The perspective view of the heat insulation cover body which concerns on this invention Partial expanded sectional view of the injection | emission part equipped with the heat insulation cover body which concerns on other Embodiment 1 of this invention. Partial expanded sectional view of the injection | emission part equipped with the heat insulation cover body which concerns on other Embodiment 2 of this invention.

  Hereinafter, embodiments for carrying out the invention will be described with reference to FIGS.

<1> An injection part of an injection molding machine.
FIG. 1 shows an example of an injection unit 10 of an injection molding machine.
The injection unit 10 is wound around the heating cylinder 20, a screw 21 housed in the heating cylinder 20, a hopper 22 for supplying the raw material resin into the heating cylinder 20, and an outer periphery of the heating cylinder 20 at a predetermined interval. The plurality of heaters 23 are provided.
In the present invention, the heating cylinder 20 is covered using a heat insulating cover body 30 described later.

<1.1> Heating cylinder.
The heating cylinder 20 is a cylindrical body that accommodates the screw 21 and has an injection nozzle 24 at the tip thereof.

<1.2> Screw.
The screw 21 in the heating cylinder 20 can be rotated by being driven by a hydraulic motor or the like, and can be advanced and retracted by receiving the propulsive force of the injection cylinder.

<1.3> Heater.
The heater 23 is a known band heater and is externally provided on the outer peripheral surface of the heating cylinder 20 with a space therebetween. Each heater 23 is connected to a plurality of lead wires 25, and the heater 23 heats the heating cylinder 20 by supplying power through the lead wires 25.

<2> Thermal insulation cover body.
Referring to FIGS. 1 and 2, the heat insulating cover body 30 includes a plurality of split cylinders 31, 31 that can be externally mounted on the heating cylinder 20 at intervals, and an arc-shaped intermediate provided on the inner peripheral surface of each split cylinder 31. The spacer 40 is provided with arc-shaped terminal spacers 45 provided at both ends of the inner peripheral surface of each split cylinder 31, and holding means for holding the split cylinders 31 and 31 in a cylindrical shape.
In this example, a mode in which the heat insulating cover body 30 has a circular cross section will be described. However, the cross sectional shape of the heat insulating cover body 30 may be rectangular, elliptical, or the like. In short, it suffices if a space having an annular shape of a sealing structure can be formed between the peripheral surfaces of the heat insulating cover body 30 and the heating cylinder 20 when the heating cylinder 20 is packaged.

<2.1> Split tube.
The split cylinder 31 is a split body obtained by splitting a cylindrical body having a diameter larger than that of the heating cylinder 20 into a plurality along the axial direction, and is formed by molding.
In this example, the split cylinders 31, 31 show a form in which only the range of the heating cylinder 20 is packaged, but the cylinders 31, 31 may be packaged including the range of the nozzle 24.
About the division | segmentation number of the split cylinder 31, it is not limited to the form which divided the cylinder, and you may divide | segment into three or more.
In this example, the split cylinders 31 and 31 are separated and independent. However, one long side of the split cylinders 31 and 31 facing each other is abutted, and a hinge structure is provided at the abutting position so as to be rotatable. You may pivot.

When one or both of the side end surfaces 31a of the split cylinders 31 and 31 are formed with semicircular cutout grooves 31b and 31b through which the lead wires 25 are inserted, and the split cylinders 31 and 31 are assembled into a cylindrical shape. A pair of cutout grooves 31b and 31b are combined to form a drawing hole 32 having a circular cross section.
The cutout grooves 31b and 31b (drawing holes 32) are set to the minimum dimensions that allow the lead wires 25 to be drawn so that an excessive gap is not formed in the drawing portion when the lead wire 25 is inserted.
The number and positions of the drawing holes 32 can be matched with the number of the lead wires 25 and the drawing position.

<2.1.1> Example of split cylinder material.
The split cylinder 31 is an inorganic molded article excellent in heat resistance, heat insulation, flame retardancy, molding processability, and economy.
As a material of the split cylinder 31, for example, a ceramic molded product mainly composed of an excellent harmless ceramic fiber can be used.
If it is a ceramic mold, it can be easily formed using an inexpensive material.
The split cylinder 31 is not limited to the above-described material, and a known inorganic material such as fiber reinforced cement or gypsum can be applied.

<2.2> Spacer.
The intermediate spacer 40 and the terminal spacer 45 are a plurality of functions that function as a heat insulating layer between the peripheral surfaces of the split cylinders 31, 31 and the heating cylinder 20, and to maintain the spacing between the split cylinders 31, 31 from the outer peripheral surface of the heating cylinder 20 The annular space 33 is a molded product having a partitioning material function for arranging the annular space 33 along the longitudinal direction of the heating cylinder 20.
The inner diameters of the spacers 40 and 45 have dimensions that allow contact with the outer peripheral surface of the heating cylinder 20, and the peripheral lengths of the spacers 40 and 45 are the spacers 40 and 45 when the split cylinders 31 and 31 are assembled into a cylindrical shape. 45 is the dimension which exhibits a ring.
The spacers 40 and 45 each having an arc shape are integrally fixed to the inner peripheral surface of the split cylinder 31 with an adhesive or the like.
The spacers 40 and 45 may be integrally formed of the same material as the split cylinder 31.

<2.2.1> Spacer material.
The intermediate spacer 40 and the terminal spacer 45 are inorganic molded products having excellent heat resistance, heat insulation, flame retardancy, molding processability, and economy.
As a material of both the spacers 40 and 45, for example, a molded product containing potassium silicate can be used.
Both the spacers 40 and 45 are not limited to the above-described materials, and a known inorganic material can be applied.

<2.2.2> Installation interval of the intermediate spacer.
The installation interval of the intermediate spacers 40 corresponds to the installation interval of the heaters 23, and the intermediate spacers 40 are positioned between the adjacent heaters 23.
This is to define an independent annular space 33 for each heater 23.

<2.3> Holding means for split cylinder.
As a means for holding the split cylinders 31, a known binding tool such as a band or a belt having a total length capable of restraining the heat insulating cover body 30 can be applied, and the adjacent split cylinders 31, 31 are connected to each other. A known connector having a possible length can be applied.

[How to assemble the thermal insulation cover]
Next, a method for assembling the heat insulating cover body 30 will be described.

<1> Assembly of split cylinder.
With the spacers 40 and 45 facing the outer peripheral surface of the heating cylinder 20, the split cylinders 31 are externally assembled and assembled into a cylindrical shape.

<2> Lead wire drawing.
At this time, the lead wire 25 is inserted into the cutout grooves 31 b and 31 b (drawing holes 32) formed in the split cylinders 31 and 31 and pulled out to the outside of the heat insulating cover body 30.

<3> Fixing the split cylinder.
The split cylinders 31, 31 assembled into a cylindrical shape using the split cylinder holding means are fixed so as not to be separated, and the exterior work of the heat insulating cover body 30 is completed.
The spacers 40 and 45 attached to the inner peripheral surface of the heat retaining cover body 30 abut on the outer peripheral surface of the heating cylinder 20, whereby an annular space 33 having a sealed structure is formed for each heater 23.
As described above, the cylindrical heat insulation cover body 30 can be assembled on the peripheral surface of the heating cylinder 20 with a simple operation of simply mounting and fixing the split cylinders 31 from the outside of the heating cylinder 20. A plurality of independent annular spaces 33 can be formed inside the heat insulating cover body 30.

[Operation of injection molding machine]
Next, the operation of the injection molding machine will be described.

<1> Injection molding.
In FIG. 1, the raw material resin in the hopper 22 is introduced into the heating cylinder 20, the screw 21 is rotated to feed the raw material resin to the leading end side of the heating cylinder 20, and at the same time, a heater 23 is used from outside the heating cylinder 20. The raw material resin is heated and melted.
When a predetermined amount of molten resin is stored in front of the screw 21, the screw 21 moves forward in the heating cylinder 20 to inject the molten resin from the nozzle 24 at the tip of the heating cylinder to mold a resin product having a predetermined shape.

<2> The heat insulating action of the heat insulating cover body.
When the raw material resin is heated by the plurality of heaters 23, the inside of the heating cylinder 20 is heated from each heater 23 and is radiated outward.
Since the annular space 33 functioning as a heat insulating layer and the heat insulating cover body 30 having an excellent heat insulating action cooperate to block heat dissipation from each heater 23, it is possible to effectively suppress heat dissipation to the atmosphere. it can.

<3> Reason why the heat insulation effect is high.
The reason why the heat insulating cover 30 has a high heat insulating effect is that an independent annular space 33 is defined for each heater 23 and individually insulated, and both spacers 40 and 45 are formed of a material having excellent heat insulating properties. This is due to the combined factor of increasing the airtightness of the annular space 33.
In particular, the annular space 33 is isolated from the outside air by the highly heat-insulating split cylinder 31 and both the spacers 40 and 45, thereby suppressing the movement of the air inside the heat insulating cover body 30, so that each annular space 33 is independently insulated and insulated. It was configured to be a room.
In other words, the temperature interference between the adjacent annular spaces 33 is avoided, and each heater 23 can be individually insulated.
Thereby, compared with the case where all the heaters 23 are kept warm in one space without providing the spacers 40 and 45 inside the heat insulation cover body 30, the heat insulation effect of the heat insulation cover body 30 becomes remarkably high.

By selecting the spacers 40 and 45 and the split cylinder 31 to the optimum thickness for each annular chamber 33, the heat insulation performance can be adjusted optimally for each annular chamber 33, and the optimum heat insulation effect according to the heating temperature of each heater 23. Can be demonstrated.
In an actual injection molding machine, the heating temperature of all the heaters 23 arranged in the heating cylinder 20 may not be constant, so that the heating temperature sequentially increases from the base end of the heating cylinder 20 toward the nozzle 24. Even when it is set to, effective heat insulation and heat insulation are possible.

In the present invention, the lead wire 25 is pulled out to the outside through the cutout grooves 31b and 31b (drawing holes 32) formed in the split cylinders 31 and 31 in a necessary minimum size.
Therefore, the sealing performance of the heat insulating cover body 30 is enhanced, and each annular space 33 can maintain high airtightness, so that the heat insulating performance and the heat retaining performance of each annular space 33 are improved.
Furthermore, since the heat insulation cover body 30 can maintain the airtightness of the heat insulation cover body 30 simply by joining and assembling the side end surfaces of the adjacent split cylinders 31, the heat insulation cover body 30 is opened by using a heat insulating padding material after the split cylinder 31 is assembled. The work of blocking is unnecessary.

<4> Reduction effect of power consumption.
As described above, the power consumption by the heater 23 can be significantly reduced due to the high heat insulation performance by the heat insulating cover body 30, and economical injection molding becomes possible.
In particular, the economic effect associated with the reduction in power consumption is significant in medium- and large-sized injection molding machines in which the overall length of the heating cylinder 20 is long and the number of heaters 23 is large.

<5> Comparative test example of power consumption.
Using the following resin injection molding machine, a comparative test of power consumption was carried out for two types, a non-mounted type of the thermal insulation cover body 30 and a mounted type.

[Test results]

[Average power consumption reduction rate]
When the average power consumption without the heat insulation cover body is A and the average power consumption with the heat insulation cover body is B, the reduction rate of the average power consumption is obtained by the following equation.
(AB) / A (Formula 1)
Therefore, the average power consumption reduction rate defined above was −22.7%, and an energy saving effect of more than 20% was confirmed as compared with the case where the heat insulating cover body 30 was not attached.
Although the conventional heat insulating cover body can achieve the effect of reducing power consumption to some extent, the cost of the heat insulating cover body is high and the average power consumption reduction rate is as small as -10%.
In the heat insulating cover body 30 of this example, the split cylinder 31 and the spacers 40 and 45 are thickened, or the diameter difference between the heating cylinder 20 and the heat insulating cover body 30 is increased to increase the volume of the annular space 33. By doing so, it is possible to further improve the average power consumption reduction rate.

<6> Removal of the heat insulating cover body.
When maintenance of the heating cylinder 20 is necessary, the thermal insulation cover body 30 can be easily detached from the heating cylinder 20 by releasing each split cylinder 31 after releasing the split cylinder holding means.

[Other embodiment 1]
In the following, other embodiments will be described. In the description, the same parts as those in the above-described embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 3 shows a partially enlarged cross-sectional view of the injection section 10 in which the heating cylinder 20 is covered with another heat insulating cover body 30A configured by lining the heat insulating mat 46 on the entire exposed inner peripheral surface of each split cylinder 31.
The heat retaining mat 46 in this example is attached to the entire exposed inner peripheral surface of each split cylinder 31 except for the spacers 40 and 45 by adhesion.

<1> Thermal insulation mat.
The heat insulating mat 46 is a multilayered fibrous material (blanket-like material) that is manufactured by intricately mixing fibers and has high heat insulating performance and is rich in heat resistance and incombustibility.
As a material of the heat insulating mat 46, for example, a known ceramic fiber blanket, glass wool or the like which is harmless to a living body can be applied.

<2> Effects of this example.
In this example, the thermal insulation mat and the thermal insulation performance in each annular space 33 are improved by lining the thermal insulation mat 46 on the split cylinder 31 of the thermal insulation cover body 30A, so that the power consumption of the injection molding machine is reduced. Increases effectiveness.

[Other embodiment 2]
FIG. 4 shows a portion of the injection unit 10 in which the casing 311 of each split cylinder 31 is formed of a lock wall, and the outer periphery of the casing 311 is covered with a heat insulating layer 312 to cover the heating cylinder 20 with another heat retaining cover 30B. An enlarged sectional view is shown.
The provision of the spacers 40 and 45 on the inner periphery of the split mold 31 is the same as in the embodiment described above.

<1> A split cylinder housing.
The casing 311 is a heat insulating material with high heat retention performance and abundant heat resistance and incombustibility. For example, a case in which a known hardener is added to a fiber such as a lock wall, glass fiber, or ceramic fiber is applied. Can do.

<2> Thermal barrier layer.
The heat shield layer 312 is a heat insulating film for blocking heat radiation from the housing 311 to the atmosphere. For example, special coating glass cloth, glass fiber cloth, silica fiber cloth, alumina fiber cloth, heat shield paint, etc. are applied. can do.

<3> Effects of this example.
The heat insulation cover body 30B of this example can exhibit the heat insulation performance equivalent to the heat insulation cover bodies 30 and 30A described above.
Furthermore, if an inexpensive lock wall or the like is selected as the material of the housing 311, the manufacturing cost of the heat insulating cover body 30 </ b> B can be further reduced.

DESCRIPTION OF SYMBOLS 10 ... Injection part 20 of injection molding machine ... Heating cylinder 21 ... Screw 23 ... Heater 24 ... Nozzle 25 ... Lead wire 30 ... Heat insulation cover body 30A ... Heat insulation cover body 30B ... Heat insulation cover body 31 ... Split tube 311 ... Case 312 ... Heat shield layer 32 ... ..Drawer hole 33 ... annular space 40 ... intermediate spacer 45 ... terminal spacer

Claims (7)

A heat insulating cover body covering an injection part of an injection molding machine comprising a heating cylinder and a plurality of heaters wound around the outer periphery of the heating cylinder at a predetermined interval,
A plurality of split cylinders obtained by dividing a cylindrical body having a larger diameter than the heating cylinder along the axial direction;
A plurality of spacers formed by molding a material excellent in heat insulation, and provided along the circumferential direction on the inner peripheral surface of the split cylinder,
Holding means for holding the plurality of split cylinders in a cylindrical shape,
While separating the plurality of split cylinders from the heating cylinder through the spacer,
A plurality of annular spaces surrounding each heater are defined between the plurality of split cylinders and the peripheral surface of the heating cylinder via the spacer that is in contact with the outer peripheral surface of the heating cylinder.
Insulation cover body.   A notch groove into which a lead wire extending from the heater can be inserted is formed on a side end surface of the plurality of split cylinders, and the lead wire can be pulled out of the heat insulating cover body through a lead hole formed by abutting the pair of notch grooves. The heat insulating cover body according to claim 1, wherein the heat insulating cover body is configured.   The heat insulating cover body according to claim 1, wherein a heat insulating mat is attached to an inner peripheral surface of the split tube.   The plurality of spacers are composed of intermediate spacers provided on the inner peripheral surface of each split tube and terminal spacers provided on both ends of the inner peripheral surface of each split tube, and both the spacers are molded articles containing potassium silicate. The heat insulation cover body according to any one of claims 1 to 3, wherein the heat insulation cover body is characterized.   The heat insulating cover body according to any one of claims 1 to 4, wherein the split tube is a molded product of ceramic fiber.   The heat insulating cover body according to any one of claims 1 to 4, wherein the split tube is formed of a rock wall casing. An injection molding machine comprising a heating cylinder having a nozzle at the tip and a plurality of heaters wound around the outer periphery of the heating cylinder at a predetermined interval,
The heat insulation cover body according to any one of claims 1 to 6 is mounted on the heating cylinder,
While separating the plurality of split cylinders from the heating cylinder through the spacer,
A plurality of annular spaces surrounding each heater are defined between the plurality of split cylinders and the peripheral surface of the heating cylinder via the spacer that is in contact with the outer peripheral surface of the heating cylinder.
Injection molding machine.

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