JP2000301535A - Hot air dryer for resin pellet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent damage to a mixing blade and a hopper by making it hard for the mixing blade rotating within a conical section narrowed at the lower portion of the hopper to get into contact with an air permeable screen on the outer periphery of the conical section or the hopper. SOLUTION: In the hot air dryer for resin pellets, which includes a cylindrical hopper 11 having a lower conical portion, an agitating rotary body having a rotation shaft 21 of the cantilever type coaxially housed in the hopper 11 and agitating blades 23, 23 attached to the shaft 21 and located in the conical portion, and a hot air feed device for feeding hot air into the hopper 11, and in which resin pellets fed from a feed port formed at the upper part of the hopper 11 are taken out from a delivery port formed in the lower conical portion, the shaft 21 is protruded downward from the hopper 11 so as to be rotatably supported by bearings 85, 85, and an output shaft of a motor 70 is connected with the protruded portion of the shaft to transmit power of the motor to the shaft.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot air drying apparatus for resin pellets.

[0002]

2. Description of the Related Art A thermoplastic resin used as a raw material for injection molding or blow molding has a high water content, so that it is difficult to mold and the physical properties of a molded article are deteriorated. For this reason, hot air drying of resin pellets used as a raw material for molding is widely performed before molding.

On the other hand, if pellets of polyethylene terephthalate (hereinafter, referred to as “PET resin”) are used as a molding raw material in an amorphous state, the pellets harden in a hot air drying apparatus or a hopper opening of a molding machine and cannot be molded. There is. However, since the PET resin pellets are crystallized during the hot-air drying, the PET-resin pellets can be molded by the hot-air drying. Therefore, in the case of PET resin, hot-air drying is also performed for this reason.

[0004] As this kind of hot air drying apparatus, there is an apparatus having a structure as shown in FIG. In this device, a rotary shaft (21) is disposed coaxially with a cylindrical hopper (11) formed in a conical shape in which a certain range from the lower end is contracted downward in diameter. The rotating shaft (21) has a stirring blade (23) (23)
Is installed. A duct (34) for supplying hot air from a hot air supply device (66) is connected to a lower portion of the hopper (11), and a conical portion (14) at a lower portion of the hopper (11).
The opposing conical air-permeable screens (31) are arranged at intervals on the inner surface of the air-conditioner.

In this apparatus, when an operation switch (not shown) is turned on, resin pellets are fed from an inlet (19) at the upper end of the hopper (11), and the rotating shaft (21) rotates to rotate the hopper (11). The resin pellets in the parentheses begin to be stirred, and the hot air supply device (66) is further operated to supply the dried hot air from the duct (34) into the hopper (11). Then, the resin pellets in the hopper (11) are stirred by the stirring blades (23) and (23) while the duct (3) is being stirred.
4) Dry with hot air from. After the drying operation is continued for a predetermined time, the shutter at the lower end of the hopper (11) is
Open (41) and take out the dried pellets.

[0006]

However, in the above-described conventional hot air drying apparatus, the rotating shaft (21) is in a cantilever state in which only the upper end is held, and the lower end of the rotating shaft (21) is in a free state. It is easy to shake. Also, since the conical part (14) at the bottom of the hopper (11) becomes thinner sequentially and the internal space is narrow,
Even if the swing of the lower end of the rotating shaft (21) is small, the stirring blade (23) (23)
The tip of the breathable screen (31) (breathable screen (31)
If not installed, there is a risk of contact with the inner surface of the conical part (14), and the stirring blades (23) and (23)
(31) may be damaged.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and describes a conical tubular hopper (11) having a fixed range whose diameter is contracted downward from the lower end, and the hopper (11).
A cantilevered rotation shaft (21) housed coaxially with this
A stirring rotator attached to the rotating shaft (21) and provided with stirring blades (23) (23) positioned at the conical portion, a motor for driving the stirring rotator, and the hopper ( 11) a hot air supply device for supplying hot air to the inside, and a resin that takes out resin pellets supplied from an input port formed at an upper portion of the hopper (11) from a discharge port formed in the conical portion. Hopper (11)
Stirrer blades (23) (23) rotating in the narrow conical section (14) below the
Makes it hard to come into contact with the permeable screen (31) and hopper (11) on the outer periphery, so that the stirring blades (23) (23) and hopper
The object is to prevent the damage of (11). <Item 1>

[0008]

The technical means of the present invention for solving the above-mentioned problem is that "the rotary shaft (21) is connected to the hopper
(11), the protrusion is rotatably supported by a bearing, and the output shaft of the motor and the protrusion are connected in a power transmission state. "

According to the above technical means, the lower end of the rotary shaft (21) is free because the portion of the rotary shaft (21) projecting downward from the hopper (11) is supported by the bearing. The lower portion of the rotating shaft (21) is less likely to sway as compared with the above-described conventional one. Therefore, the stirring blades (23) (23) rotating in the narrow conical space located below the hopper (11) are less likely to come into contact with the outer peripheral wall.

[0010]

The present invention has the following specific effects. Since the stirring blades (23) and (23) rotating in the narrow conical space below the hopper (11) hardly come into contact with the outer peripheral wall, the stirring blades (23) and (23) and the hopper (11) etc. Less likely to be damaged. <Claim 2> In the above item 1, "the discharge port is a shutter
When the drying operation is started, the shutter (41) is closed and the hopper (11) is dried and agitated, and then the shutter (41) is opened to open the dried resin. By gradually feeding the undried resin pellets from the upper inlet of the hopper (11) while gradually taking the pellets downward, the drying operation can be continuously performed thereafter.

<Item 3> In the above item 2, the term “the discharge port is a space between the outer periphery of the rotating shaft (21) and the inner periphery of the lower end of the hopper (11), ) Is configured by a lower shaft supported by the bearing portion and positioned below the discharge port, and an upper shaft that is vertically insertable / removable with respect to the lower shaft and connected in a detented state, A conical breathable screen (31) facing the inner surface of the conical part at a distance
The shutter (41) is provided with the rotating shaft.
(21) is constituted by a pair of slide plates each formed with a semicircular notch that abuts the hopper (21) from the diametric direction, and the upper end of the hopper (11) is covered with an openable / closable upper lid. In the above, since an air-permeable screen (31) facing the inner surface of the conical portion at intervals is provided, the hot air supplied to the conical portion from the hot air supply device is the air-permeable screen (31). After diffusing so as to surround the entire outer surface of 31), it rises through the breathable screen (31). Therefore, the resin pellet group in the hopper (11) is dried uniformly regardless of the location.

On the other hand, according to the above technical means, the air permeable screen (31) or the hopper (11) clogged with resin material powder is used.
The work of cleaning the inner surface of the lower part of the work can be easily performed. That is, when drying the recycled resin pellets obtained by crushing the molded product, the gas permeable screen (31) is clogged with the resin powder, or the resin powder adheres to the vicinity of the discharge port at the bottom of the hopper (11). In such a case, it is necessary to clean the air permeable screen (31) and the vicinity of the discharge port. When cleaning the air permeable screen (31), first open the upper lid of the hopper (11) and raise the upper shaft connected to the lower shaft supported below the conical part so that it can be inserted and removed. After that, the permeable screen (31) is taken out from the upper end opening of the hopper (11), and the permeable screen (31) and the conical portion under the hopper (11) are cleaned.

<Item 4> In the above item 3, the "the hopper
(11) is a configuration in which the conical portion and the body portion (13) following the conical portion can be vertically divided. " Here, `` split '' refers to a structure in which the trunk (13) is connected to the upper end of the conical portion by a hinge so as to be vertically rotatable, and the trunk (13) is formed from the conical portion. It is a concept that includes both a completely removable structure. In this case, the upper shaft of the rotating shaft (21) is removed at the time of cleaning the air permeable screen (31), and then the upper end of the conical portion is opened from the upper end of the body (13). Removed or the body (1
Rotate the 3) so that it falls down to open the upper end of the conical portion (14). This makes it easier to remove the breathable screen (31) and clean the inner surface of the conical portion (14).

[0014]

Next, embodiments of the present invention will be described. As shown in FIG. 1, the hot air drying apparatus for resin pellets according to the present embodiment is mounted on a gantry (51).

The hot-air drying apparatus is provided with a hopper (11) for accommodating resin pellets, an openable / closable lid (61) for covering an open upper end of the hopper (11), and attached to the lid (61). Small tank
(62), a pellet take-out cylinder (63) continuously provided below the conical portion (14), a stirring blade having a stirring blade (23) (23) and a rotating shaft (21) for stirring the pellet. A hot air generator (69) for supplying hot air from the conical portion (14) into the hopper (11) is provided.

The details of each section will be described below. [About hopper (11)] Hopper for storing resin pellets
(11) is to be divided into an upper conical portion (14) and a cylindrical body (13) thereon, and these conical portions (14) and the body (13) It is rotatably connected to a support shaft (29) described later. A discharge port (10) that opens downward is formed at the lower end of the conical portion (14).
A lower flange (56) protrudes from the outer periphery of (10).

An air blower tube (16) for connecting the inside and outside of the conical portion (14) is continuously provided in the middle of the conical portion (14) in the vertical direction, and inside the conical portion (14). Is provided with a conical permeable screen (31) formed by bending a punched metal or mesh. And the air permeable screen (31) is placed on the plurality of spacers (25) (25) welded to the inner surface of the conical portion (14), whereby the air permeable screen (31 ) And the conical part (14) have a ventilation gap connected to the entire circumference.
(12) is secured.

An upper flange (58) is provided on the outer periphery of the upper end of the conical portion (14).
The outer flange portion (30) is mounted on the upper flange (58) at the upper end of the permeable screen (31). A hopper (11) is attached to the bracket (54) projecting in the radial direction from the lower surface of the upper flange (58) so as to be rotatable up and down as described later. Also, an arm (52) protruding on the outer side of the conical portion (14) on the side opposite to the bracket (54).
A bolt (47) is attached to the arm (52) so as to be rotatable up and down, and the bolt (47) has a lower flange (15) A tightening nut (46) for tightening is screwed.

The trunk (1) connected to the upper end of the conical portion (14)
3) is formed in a cylindrical shape, and the inner diameter thereof substantially matches the diameter of the upper end opening of the conical portion (14). Body (1
The lower flange (15) projecting from the lower end of the outer periphery of (3) has a hanging piece
The hanging piece (27) has a bracket (5) projecting radially outward from the upper end of the conical portion (14).
4) It is rotatably mounted on a support shaft (29).

The lower flange (15) of the lower end of the body (13) is formed with a slit (28) that opens outwardly. 47) comes in and out. Lid covering the open top of the torso (13)
The (61) is configured so as to open and close by pivoting up and down at a hinge (39). For this reason, the hanging piece (37) hanging from the outer periphery of the lid (61) and the projecting piece (100) projecting from the trunk (13) are supported by the support shaft.
It is rotatably connected at (38).

At the upper end of the outer periphery of the body (13), the hinge (3)
A lock fitting (74) located on the side opposite to the arrangement part of (9) is provided, and the lock fitting (74) is engaged with the outer periphery of the lid (61) in a fishing hook shape from above. (75) and the engagement
It has a handle (76) for tightening (75) downward.
Then, when the handle (76) is pivoted downward from the horizontal posture with the support shaft (77) as a fulcrum, the upper surface of the lid (61) is pushed downward by the bent tip of the engagement slope (75). The lid (61) is held in a closed state.

The lid (61) is provided with an exhaust hole (60) for discharging hot air in the hopper (11) and the lid (61).
A small tank (62) having a material supply valve (59) is attached to an inlet (100a) for supplying resin pellets at the center of the small tank (62). A pipe (64) is provided continuously. Then, a small tank (62) is supplied from a material supply device (not shown) via the material supply pipe (64).
The inside is supplied with resin pellets. [About the pellet take-out cylinder (63) and the shutter (41)] Next, a shutter for opening and closing the discharge port (10) of the hopper (11).
(41) and the pellet take-out cylinder (63) connected thereto will be described.

In this embodiment, the pellet take-out cylinder (63) is formed of a tubular body having a rectangular cross section, and is provided at the boundary between the upper end of the pellet take-out cylinder (63) and the lower end of the hopper (11). Is an upper shaft (20) constituting a rotary shaft (21) as shown in FIGS.
A pair of slide plates (42) (42) having semicircular notches (40) (40) corresponding to the outer periphery of the slide plate are interposed. When the upper shaft (20) is sandwiched between the notches (40) and (40) of the slide plates (42) and (42), the periphery of the notches (40) and (40) and the cylindrical upper shaft (20) A state is formed in which minute gaps that do not allow the resin pellets to pass through are formed.

As shown in FIG. 2, the slide plates (42) (4)
2) is installed in a state of being erected on a pair of guide rails (43) (43) arranged opposite to the upper end in the pellet take-out cylinder (63), and these slide plates (42) (42) are It moves back and forth with respect to the plane of FIG. Also, slide plate (4
2) Handles (44) (44) for opening and closing operations are attached to the outer end of (42). Therefore, when the slide plates (42) and (42) are moved in the direction to separate the slide plates (42) and (42) by holding the handles (44) and (44), the inner periphery of the lower end of the conical portion (14) below the hopper (11) and the upper shaft (20) ) Is opened, and the hopper (11) communicates with the pellet take-out cylinder (63).

A discharge pipe (65) is connected to the side wall of the pellet take-out cylinder (63).
A suction device (not shown) is connected to the
3) The resin pellets inside can be taken out. [Regarding Stirring Rotator] The stirring rotator that stirs the resin pellets in the hopper (11) includes a rotating shaft (21) and stirring blades (23) (23) attached thereto. At the same time, it is driven by the motor (70).

The rotating shaft (21) is composed of a cylindrical upper shaft (20) and a lower shaft (22) connected vertically. The lower shaft (22)
Lower bearing (84) arranged on lower plate (81) corresponding to its lower end
And a sprocket (86) and a motor (70) that are rotatably supported by an upper bearing (85) disposed on an upper plate (82) above the sprocket (86) and that are attached to a lower portion of the lower shaft (22). The sprocket (87) attached to the output shaft is connected by a transmission chain (88).

As shown in FIG. 4, the upper end of the lower shaft (22) is a conical shaft portion (26) whose diameter decreases upward, and the conical shaft portion (26) is open to the upper end. An engagement groove (24) is formed.

On the other hand, the upper shaft (20) is formed with a conical hole (35) which is fitted to the conical shaft portion (26) of the lower shaft (22).
An engagement pin (36) is fixed to the upper shaft (20) so as to penetrate the depth of the conical hole (35) in the diameter direction. And the upper shaft (2
When the conical hole (35) portion of (0) is externally fitted to the conical shaft portion (26) of the lower shaft (22), the engaging pin (36) engages with the engaging groove (27) at the upper end of the conical shaft portion (26). 24), whereby the upper shaft (20) and the lower shaft (22) are fitted and connected in a pullable state and a detent state.

The stirring blade (23) attached to the upper shaft (20) of the rotating shaft (21) has a long side of a rectangular plate (33) welded to the outer periphery of the shaft body (32) as shown in FIG. One end of the shaft body (32) is welded while being inserted into an insertion hole (200) diametrically penetrating the upper shaft (20) constituting the rotating shaft (21). ing. The stirring blades (23) and (23) function to slightly lift the resin pellets on the upper surface of the rectangular plate (33) (see FIG. 5) as they rotate, and the rectangular shape of the stirring blades (23) disposed below. Plate (33) is a rectangular plate of stirring blades (23) arranged above
The inclination angle with respect to the horizontal is larger than in (33).
Therefore, the stirring blade (23) located below has a greater degree of stirring the resin pellets than the upper one. [About hot air supply device (69)] A heater (not shown) is provided in a heating device (66) constituting the hot air supply device (69), and the heat generated by the heater is generated by a fan (49) by a hot air discharge cylinder. (67) → duct (68) → blower (16) → inside of hopper (11) → flow through the exhaust port (60).

[Operation] Next, the operation of the hot air drying apparatus according to the above embodiment will be described. In the present embodiment, a case where an amorphous PET resin pellet is dried while being crystallized will be exemplified. In this device, the discharge port (10) at the lower end of the hopper (11)
Is kept closed by the shutter (41), and in this state, a predetermined amount of undried PET resin pellets is supplied into the hopper (11). That is, the material supply valve (59) at the top of the hopper (11) is opened, and a predetermined amount of resin pellets is supplied from a pellet supply device (not shown) connected to the material supply pipe (64). A predetermined amount of resin pellets are stored in the parentheses.

Next, the hot air supply device (69) composed of the heating device (66) and the fan (49) is operated to put 140 ° C. in the hopper (11).
The hot air of ~ 150 ° C is supplied and the motor (70) is operated. When the hot air from the hot air supply device (69) flows into the hopper (11), the hot air diffuses so as to surround the entire outer periphery of the permeable screen (31) and passes through the permeable screen (31). The hot air rises and heats the resin pellets in the hopper (11) to dry them while crystallizing them. During this crystal drying, the lower shaft (22) of the rotating shaft (21) is rotated by the motor (70). Then, the upper shaft (20) fitted and connected to the upper end of the lower shaft (22) also rotates, whereby the stirring blades (23) and (23) stir the resin pellets in the hopper (11).

When the resin pellets in the hopper (11) are crystallized and dried due to the continuation of the drying operation, the resin pellets change from transparent to white. This is visually confirmed, for example, and then the shutter (41) Release manually.
That is, the discharge port (10) is opened by separating the slide plates (42) and (42) from each other, and the resin pellets crystallized and dried from the discharge port (10) are placed in the pellet take-out cylinder (63). The resin pellets in the pellet take-out cylinder (63) are continuously sucked by a suction device (not shown) connected to the discharge pipe (65), and are removed. In addition, the material supply valve (59) at the upper end of the hopper (11) is opened, and undried resin pellets that have not been crystallized are continuously supplied into the hopper (11). Thereby, the resin pellets having been crystal-dried can be continuously taken out from the blower tube (16).

In this case, the lower end of the rotating shaft (21) composed of the upper shaft (20) and the lower shaft (22) is supported by the lower bearing (84) and the upper bearing (85). The lower part of the rotating shaft (21) is less likely to swing in the radial direction than the above-described conventional one in which the upper end of (21) is supported in a cantilever state. Therefore, there is less fear that the stirring blades (23) (23) in the narrow conical portion (14) whose inner diameter is reduced downward and the permeable screen (31) come into contact, and these stirring blades (23) (23) And the possibility of damaging the air-permeable screen (31) is reduced.

Next, the breathable screen (31) and the conical portion (14)
The operation of cleaning the inside will be described. When cleaning the inside of the breathable screen (31) or the conical portion (14) clogged with resin material powder, rotate the lid (61) upward after releasing the lock fitting (74), and Thereby, the upper end of the hopper (11) is opened. Next, the upper shaft (20) of the rotating shaft (21) is forcibly pulled upward from the lower shaft (22), and the upper shaft (20) is taken out of the hopper (11).

Next, the tightening nut (46) fixing the joint between the conical portion (14) and the body (13) is loosened, and the bolt (47)
Is rotated downward as shown by the imaginary line in FIG. next,
The torso (13) is turned laterally at the hinge (39). Then, the upper end of the conical part (14) is opened and the breathable screen (31)
Is exposed. Therefore, this exposed breathable screen (3
1) is removed and cleaned, and resin powder attached to the inner surface of the conical portion (14) and the discharge port (10) is removed. [Others] In the above embodiment, the trunk (13) of the hopper (11) is rotated at the hinge (39) with respect to the cone (14). It may be completely removed from (14). In the above embodiment, the case where the PET resin pellets are crystal-dried has been described as an example, but the present invention can be applied to the case where other resin pellets are dried.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a hot air drying apparatus for resin pellets according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a shutter (41) of FIG. 1;

FIG. 3 is an enlarged plan view of a shutter (41) of FIG. 1;

FIG. 4 is an enlarged sectional view of a joint portion between the upper shaft (20) and the lower shaft (22) in FIG. 1;

FIG. 5 is a perspective view of a main part of the stirring blade (23).

FIG. 6 is an explanatory view of a conventional example.

[Explanation of symbols]

 (11) ・ ・ ・ Hopper (13) ・ ・ ・ Body (21) ・ ・ ・ Rotating shaft (23) ・ ・ ・ Stirring blade (31) ・ ・ ・ Ventilation screen (41) ・ ・ ・ Shutter (84)・ ・ ・ Lower bearing (85) ・ ・ ・ Upper bearing

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) BN25 BQ02 BQ08 BQ31 BQ34 BQ45 BQ52

Claims (4)

[Claims] 1. A conical cylindrical hopper (11) having a predetermined range whose diameter is contracted downward from a lower end, and a cantilevered state accommodated coaxially in the hopper (11). A rotating shaft for rotation provided with a rotating shaft (21), stirring blades (23) and (23) attached to the rotating shaft (21) and located in the conical portion, and the rotating shaft for stirring. A motor, and a hot air supply device for supplying hot air into the hopper (11), wherein the resin pellets supplied from an input port formed at an upper portion of the hopper (11) are formed in the conical portion. In the hot air drying apparatus for resin pellets taken out from the discharge port, the rotating shaft (21) is projected downward from the hopper (11), and the projected portion is rotatably supported by a bearing portion, and the output shaft of the motor and A hot air drying device for resin pellets, wherein the projecting portion is connected to a power transmission state. 2. The hot air drying apparatus for resin pellets according to claim 1, wherein said discharge port is opened and closed by a shutter (41). 3. The hot air drying apparatus for resin pellets according to claim 2, wherein the discharge port is provided on an outer periphery of the rotating shaft (21) and the hopper (11).
The rotating shaft (21) is supported by the bearing portion and is located below the discharge port, and is vertically insertable and removable with respect to the lower shaft. An upper shaft connected in a detent state, and a conical air-permeable screen (31) opposed to the inner surface of the conical portion at an interval and provided with the shutter (41) Is constituted by a pair of slide plates each formed with a semicircular notch that abuts the rotary shaft (21) from the diametrical direction, and the upper end of the hopper (11) is openable and closable. Hot air drying device for resin pellets covered with. 4. The hot air drying apparatus for resin pellets according to claim 3, wherein the hopper (11) has a configuration in which the conical portion and a body (13) above the conical portion can be vertically divided. , Hot air drying equipment for resin pellets.