PVC hot melt special filter

Abstract

The invention discloses a special filter for PVC hot melt, including a filter body and a heating device, wherein the filter body includes a feed part with a feed channel, a discharge part with a discharge channel, a filter part driven by a power source is arranged between the feed channel and the discharge channel, and the filter part is sealed with the feed channel and the discharge channel through a sealing part. The advantages of the invention are ingenious structure and reasonable design, which fills the gap of no special filter in domestic and foreign PVC production lines, not only improves the qualified rate and quality of products, but also improves production efficiency, thereby reducing energy consumption, and can also shorten the replacement time of the filter screen to the maximum (the replacement time is shortened to less than 1 minute), effectively avoiding the solidification of the PVC melt during the screen replacement process; at the same time, the special steel sliding plate, the first special steel sealing ring and the second special steel sealing ring have good wear resistance, which prolongs the service life of the filter body.

Description

Technical Field

[0001] The invention relates to a melt filter, in particular to a special filter for PVC hot melt. Background Art

[0002] In the production process of hot melts such as PP, PE, and PVC, mechanical impurities will inevitably appear in the hot melt, so a filter is usually added between the extruder and the molding die to filter and homogenize the hot melt. Compared with PP hot melt and PE hot melt, the melting point of PVC melt is usually between 120 and 200°C. It will age and solidify if it stays at the melting point temperature for a maximum of 20 minutes. It is a temperature-sensitive plastic recognized by the plastics industry and has strict requirements on filtering time.

[0003] At present, there is no dedicated filter for PVC plastic production line. The filter used is traditional plate filter, which has poor sealing performance and leakage performance, and has poor wear resistance and short service life. There are many dead corners in the filter channel. At the same time, due to the short residence time of PVC melt, aging will inevitably occur in the dead corners during the filtration process, which will reduce the quality of PVC melt. Since the filter screen is fixedly installed inside the filter through a connector, the filter head needs to be frequently disassembled when replacing the filter screen, which is labor-intensive and the extruder downtime is long, thereby reducing the production capacity of the entire production line. In addition, due to the short residence time of PVC melt, once the screen change time exceeds its residence time, the PVC hot melt will solidify in the filter channel, thereby affecting the normal operation of the entire production line. Summary of the invention

[0004] The invention aims to provide a PVC hot melt filter which is resistant to high temperature, highly wear-resistant, has good sealing performance and is easy and quick to replace the filter screen, thereby shortening the downtime of the extruder and improving the production capacity and product quality of the PVC plastic production line.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The PVC hot melt filter of the present invention comprises a filter body for filtering PVC melt and a heating device for heating and keeping the filter body warm. The filter body comprises

[0007] A feeding part, which has a feeding channel, and the feeding channel is connected to the outlet of the extruder;

[0008] A discharge portion having a discharge channel, wherein the discharge channel is connected to the inlet of the forming mold;

[0009] A filtering part, which is arranged between the feed channel and the discharge channel and is used for filtering and homogenizing the PVC melt coming out of the extruder;

[0010] a power source, which is connected to the filter part as a whole through a connecting piece and is used to drive the filter part to move back and forth; and a sealing part, which includes a first sealing part arranged at the bottom of the feed channel and a second sealing part arranged at the top of the discharge channel, and is used to ensure the sealing performance of the filter body and prevent the PVC melt from flowing out of the filter body during filtering;

[0011] Among them, the filter part, the feed channel and the discharge channel correspond to each other up and down, and the PVC melt coming out of the extruder enters the feed channel, and enters the molding mold through the discharge channel after being filtered by the filter part; when the filter part needs to be replaced, the power source drives the connecting part to move outward along the sliding channel between the feed part and the discharge part, and pushes the filter part out.

[0012] The power source is a hydraulic cylinder or a pneumatic cylinder installed outside the filter body.

[0013] The power source is a hydraulic cylinder, and the cylinder body is fixedly connected to the filter body through a connecting frame.

[0014] The connecting piece is a special steel sliding plate, one end of which is fixedly connected to the piston rod of the hydraulic cylinder or the air cylinder, and the other end extends into the sliding channel. A T-shaped limit block is inserted at the other end of the sliding channel to limit the special steel sliding plate.

[0015] A stepped mounting hole is provided on the special steel sliding plate in the sliding channel, and the filter part comprises a porous support block clamped in the stepped mounting hole and a filter screen horizontally arranged on the upper surface of the porous support block.

[0016] The first sealing member includes a first special steel sealing ring composed of a first sealing ring and a second sealing ring, which is a stepped structure with a small front and a large rear; the second sealing ring is clamped in the convex groove of the feed channel, and its front surface is sealed and connected to the bottom wall of the convex groove by an elastic metal sealing ring, while its rear surface is sealed and slidably connected to the front surface of the special steel sliding plate; the outer ring surface of the first sealing ring is sealed in contact with the side wall of the feed channel, and its inner surface extends outward from the top of the inner ring surface of the second sealing ring to the front part of its outer ring surface, forming a conical connecting port connected to the feed channel.

[0017] The rear surface of the first special steel sealing ring is provided with a first filling groove in an annular structure, in which a graphite sealing ring is clamped, which is used to seal the special steel sliding plate and the first special steel sealing ring together to prevent the PVC melt from overflowing.

[0018] The cross section of the elastic metal sealing ring is a V-shaped structure with the opening facing inwards.

[0019] The second sealing member is a second special steel sealing ring mounted on the top of the discharge channel, and a second filling groove in an annular structure is provided on the front surface thereof. The graphite sealing ring mounted in the second filling groove seals the special steel sliding plate and the second special steel sealing ring together to prevent the PVC melt from overflowing.

[0020] The heating device comprises a first heater attached to the upper surface of the filter body and a second heater attached to the lower surface of the filter body, and is used for heating and keeping the filter body warm.

[0021] The advantages of the present invention are ingenious structure and reasonable design, which fills the gap of no special filter in domestic and foreign PVC production lines, not only improves the qualified rate and quality of products, but also improves production efficiency, thereby reducing energy consumption, and can also shorten the replacement time of the filter screen to the maximum extent, effectively avoiding the solidification of PVC melt during the screen replacement process; at the same time, the special steel sliding plate, the first special steel sealing ring and the second special steel sealing ring have good wear resistance, which prolongs the service life of the filter body. The specific advantages are as follows:

[0022] 1) The special steel sliding plate, the first special steel sealing ring and the second special steel sealing ring of the present invention are all made of wear-resistant and high-temperature resistant special steel, so that the filter body has high temperature resistance and high wear resistance, and the service life of the filter body is extended; at the same time, the graphite sealing ring on the bottom of the first special steel sealing ring disconnects its lower surface, and the graphite sealing ring clamped in the upper surface of the second special steel sealing ring disconnects its upper surface, reducing the contact area between the first special steel sealing ring and the upper surface of the special steel sliding plate, and the contact area between the second special steel sealing ring and the lower surface of the special steel sliding plate, reducing friction, and further extending the service life of the filter body.

[0023] 2) The hydraulic cylinder of the present invention drives the special steel sliding plate to translate back and forth left and right along the sliding channel. The filter screen of the filtering part is arranged on the special steel sliding plate. The hydraulic cylinder can quickly (within 1 second) push the filter screen out of the filter body through the special steel sliding plate, so as to realize the rapid replacement of the filter screen (shortening the replacement time to within 1 minute), thus shortening the downtime of the extruder to the maximum extent, thereby effectively avoiding the probability of aging of the PVC melt during the replacement process, maximizing the degree of automation and production capacity of the growth line, and improving production efficiency.

[0024] 3) The feed channel of the present invention is gap-sealed with the first special steel sealing ring, and the pressure of the PVC melt is used to achieve an inelastic automatic compensatory seal between the two, which has a good sealing effect and effectively avoids dripping; at the same time, the conical connecting port of the first special steel sealing ring has no dead angle contact with the feed channel, which can prevent solidification from occurring in the dead angle.

[0025] 4) The filter channel composed of the feed channel, the first special steel sealing ring, the filter part, the second special steel sealing ring and the discharge channel of the present invention realizes a contact connection without dead angles, thereby avoiding the solidification phenomenon at the dead angles caused by the existence of dead angles, and extending the maintenance cycle of the filter body. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of the present invention.

[0027] Figure 2 yes Figure 1 Left view of .

[0028] Figure 3 yes Figure 1 AA section view of the structure.

[0029] Figure 4 yes Figure 3 Schematic diagram of the enlarged structure of part B in the middle. DETAILED DESCRIPTION

[0030] The present invention Figure 1 The upward direction is up, and the reverse direction is down. Figure 1 The left direction is left, and the opposite direction is right. Figure 2 The upward direction in is the forward direction, Figure 2 The downward direction in the figure is the backward direction. The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments.

[0031] like Figure 1-4 As shown, the PVC hot melt filter of the present invention comprises a filter body for filtering PVC melt and a heating device for heating and keeping the filter body warm;

[0032] The heating device comprises a first heater 1.1 attached to the upper surface of the filter body, and a second heater 1.2 attached to the lower surface of the filter body. The first heater 1.1 and the second heater 1.2 are connected to the electric control box of the extruder to heat and keep the PVC melt flowing out of the extruder warm.

[0033] The filter body comprises a feed portion 2.1 which is fixedly connected to the outlet of the extruder by bolts and has a feed channel 2.2 which is connected to the outlet of the extruder;

[0034] The discharge part 3.1 is fixedly connected to the outlet of the forming mold by bolts, and has a discharge channel 3.2 connected to the inlet of the forming mold, and the discharge channel 3.2 and the feed channel 2.2 are connected to each other;

[0035] A filter unit, arranged between the feed channel 2.2 and the discharge channel 3.2, for filtering and homogenizing the PVC melt coming out of the extruder;

[0036] A power source is connected to the filter part through a connecting piece and is used to drive the filter part to move back and forth; and a sealing part, which includes a first sealing part arranged at the bottom of the feed channel 2.2 and a second sealing part arranged at the top of the discharge channel 3.2, and is used to ensure the sealing performance of the filter body and prevent the PVC melt from flowing out of the filter body during filtering;

[0037] Among them, the feed channel 2.2, the filter part and the discharge channel 3.2 are connected. The PVC melt coming out of the extruder enters the feed channel 2.2, is filtered by the filter part, and then enters the molding mold through the discharge channel 3.2; when the filter part needs to be replaced, the power source drives the connecting part to move outward along the sliding channel between the feed part 2.1 and the discharge part 3.1, and pushes the filter part out.

[0038] like Figure 1-4 As shown, the power source is a hydraulic cylinder 4.1 installed outside the filter body, the cylinder body of the hydraulic cylinder 4.1 is fixedly connected to the filter body through a connecting frame 4.2, and the hydraulic cylinder 4.1 is connected to the hydraulic station through an oil pipe;

[0039] The connecting piece is a special steel sliding plate 5 made of tool steel or high-speed tool steel. The right end of the special steel sliding plate 5 is fixedly connected to the piston rod of the hydraulic cylinder 4.1, and the left end thereof slides from one end of the sliding channel and from the right end of the sliding channel to the inside of the sliding channel; a T-shaped limit block 6 is inserted at the left end of the sliding channel, and the blocking section of the limit block 6 extends into the sliding channel and is fixedly connected to the special steel sliding plate 5, while the limit section at the outer end thereof is blocked on the outside of the filter body, so as to limit the special steel sliding plate 5;

[0040] A stepped mounting hole is provided on the special steel sliding plate 5 located in the sliding channel. The filter part includes a porous support block 7.1 mounted in the stepped mounting hole, and a filter screen 7.2 horizontally arranged on the upper surface of the porous support block 7.1. The filter part is coaxial with the feed channel 2.2 and the discharge channel 3.2, ensuring that the PVC melt coming out of the feed channel 2.2 smoothly enters the discharge channel 3.2 after being filtered by the filter screen 7.2. When the filter screen 7.2 needs to be replaced, the hydraulic cylinder 4.1 drives the special steel sliding plate 5 and the filter part to quickly pass through the filter body along the sliding channel (controllable within 1 second), which not only reduces the difficulty of replacing the filter screen 7.2, but also shortens the replacement time of the filter screen 7.2 to within 1 minute, shortens the downtime of the extruder, and solves the problem that the PVC melt is easy to age and solidify when the traditional filter is replaced, but also maximizes the degree of automation of the growth line, increases the production capacity of the production line, and further improves production efficiency;

[0041] The first sealing member of the sealing part comprises a first special steel sealing ring 8.1 (the first special steel sealing ring 8.1 is made of die steel) composed of a first sealing ring and a second sealing ring, which is a stepped structure with a small front and a large rear, and the first special steel sealing ring 8.1 is an integrally formed structure; the rear part of the feed channel 2.2 is expanded outward to form a convex groove, and the second sealing ring is clamped in the convex groove. The front surface of the second sealing ring is sealed and connected with the top surface of the convex groove through an elastic metal sealing ring 8.2 (whose cross section is an inwardly opened V-shaped structure), and a gap is set between the front surface of the second sealing ring and the feed channel 2.2 and is connected through an elastic metal sealing ring 8.2. The sealing ring 8.2 is used for sealing. The outer ring surface of the first sealing ring is sealed against the side wall of the feed channel 2.2. The inner surface of the first sealing ring extends outward from the top of the inner ring surface of the second sealing ring to form a conical connection port 8.3 connected to the feed channel 2.2. The elastic metal sealing ring 8.2 and the material pressure of the PVC melt realize the elastic automatic compensation seal between the first special steel sealing ring 8.1 and the feed channel 2.2. The conical connection port 8.3 realizes the contact connection with the feed channel 2.2 without dead angles, which can not only effectively avoid the dripping of the PVC melt, but also prevent the aging and solidification at the dead angles.

[0042] The rear surface of the second sealing ring is provided with a first filling groove I and a first filling groove II in an annular structure, a graphite sealing ring C1 is clamped in the first filling groove I, and a graphite sealing ring C2 is clamped in the first filling groove II. The lower surface of the second sealing ring is sealed and slidably connected with the upper surface of the special steel sliding plate 5 through the graphite sealing ring C1 and the graphite sealing ring C2. The graphite sealing ring C1 and the graphite sealing ring C2 disconnect the surface of the second sealing ring, which not only reduces the contact area between the special steel sliding plate 5 and the friction force, but also has a sealing and lubricating effect, ensuring the sealing performance and relative sliding performance of the special steel sliding plate 5 and the first special steel sealing ring 8.1, and preventing the PVC melt from overflowing;

[0043] The second sealing member of the sealing part is a second special steel sealing ring 9 mounted on the top of the discharge channel 3.2, and a second filling groove I and a second filling groove II are provided on the front surface thereof at intervals in an annular structure, a graphite sealing ring D1 is mounted in the second filling groove I, and a graphite sealing ring D2 is mounted in the second filling groove II. The first special steel sealing ring 8.1 is sealed and slidably matched with the rear surface of the special steel sliding plate 5 through the graphite sealing ring, and the graphite sealing ring D1 and the graphite sealing ring D2 disconnect the surface of the second special steel sealing ring 9, which not only reduces the contact area between the special steel sliding plate 5 and the friction force, but also has a sealing and lubricating effect, thereby ensuring the sealing performance and relative sliding performance of the special steel sliding plate 5 and the second special steel sealing ring 9, and preventing the PVC melt from overflowing;

[0044] The conical connection port 8.3 at the front of the first special steel sealing ring 8.1 of the present invention is connected to the feed channel 2.2 without dead angle contact, the upper part of the porous support block 7.1 is in contact with the inner ring surface of the first special steel sealing ring 8.1 without dead angle contact, and the bottom of the porous support block 7.1 is connected to the discharge channel 3.2 without dead angle, thereby avoiding aging at dead angles to the greatest extent.

[0045] During actual processing, the first special steel sealing ring 8.1, the special steel sliding plate 5 and the second special steel sealing ring 9 are all made of mold steel, which has the characteristics of high temperature resistance and wear resistance, thereby extending the service life of the filter body.

[0046] When working, the installation direction of the filter body Figure 1 As shown, the feed channel and the discharge channel are horizontal channels. The raw material is plasticized and melted by the extruder to become a high-temperature PVC melt. The high-temperature PVC melt enters the feed channel 2.2 from the outlet of the extruder. The pure PVC melt filtered by the filter screen 7.2 flows into the discharge channel 3.2 through the multiple through holes of the porous support block 7.1, and finally enters the molding mold from the discharge channel 3.2 for subsequent processing. During the filtering process, the first heater 1.1 and the second heater 1.2 heat the filter body, thereby ensuring the temperature of the high-temperature PVC melt during the filtering process to avoid solidification.

[0047] When there are too many impurities on the filter screen 7.2 and the filter screen 7.2 is blocked, the extruder is turned off; the hydraulic cylinder 4.1 works to push the special steel sliding plate 5 to slide to the left along the sliding channel, so that the filter screen 7.2 quickly slides out of the filter body (the sliding out time can be controlled within 1 second), and a new filter screen 7.2 is replaced. During the replacement process, since the length of the special steel sliding plate 5 is greater than the length of the sliding channel, after the filter screen 7.2 moves to the outside of the filter body, the special steel sliding plate 5 located on the right side of the filter screen 7.2 is sealed with the first special steel sealing ring 8.1 to block the feed channel 2.2 to prevent the PVC melt from leaking out; after the replacement is completed, the hydraulic cylinder 4.1 drives the special steel sliding plate 5 and the filter part to move to the right to the initial position, and the limit block 6 continues to block the sliding channel to complete the replacement operation of the filter screen 7.2.

[0048] In the description of the present invention, it should be noted that the directions or positional relationships indicated by terms such as “front”, “rear”, “left”, “right”, “vertical”, “horizontal”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

Claims

1. A filter for PVC hot melt, characterized by: It comprises a filter body for filtering PVC melt and a heating device for heating and keeping the filter body warm, wherein the heating device comprises a first heater attached to the upper surface of the filter body and a second heater attached to the lower surface of the filter body; The filter body includes A feeding part, which has a feeding channel, and the feeding channel is connected to the outlet of the extruder; A discharge portion having a discharge channel, wherein the discharge channel is connected to the inlet of the forming mold; A filtering part, which is arranged between the feed channel and the discharge channel and is used for filtering and homogenizing the PVC melt coming out of the extruder; A power source, which is connected to the filter part through a connecting piece and is used to drive the filter part to move back and forth; and a sealing part, which includes a first sealing member arranged at the bottom of the feed channel and a second sealing member arranged at the top of the discharge channel, for ensuring the sealing performance of the filter body and preventing the PVC melt from flowing out of the filter body during filtering; The filter part, the feed channel and the discharge channel correspond to each other vertically, and the PVC melt coming out of the extruder enters the feed channel, and enters the molding die through the discharge channel after being filtered by the filter part; when the filter part needs to be replaced, the power source drives the connecting piece to move outward along the sliding channel between the feed part and the discharge part, and pushes the filter part out; The power source is a hydraulic cylinder installed on the outside of the filter body, and its cylinder body is fixedly connected to the filter body through a connecting frame; the connecting piece is a special steel sliding plate, one end of which is fixedly connected to the piston rod of the hydraulic cylinder or the air cylinder, and the other end extends into the sliding channel, and the other end of the sliding channel is inserted with a T-shaped limit block for limiting the special steel sliding plate; the special steel sliding plate located in the sliding channel is provided with a stepped mounting hole, and the filter part includes a porous support block clamped in the stepped mounting hole, and a filter screen horizontally arranged on the upper surface of the porous support block; The first sealing member comprises a first special steel sealing ring composed of a first sealing ring and a second sealing ring, which is a stepped structure with a small front and a large rear; the second sealing ring is clamped in the convex groove of the feed channel, and its front surface is sealed and connected to the bottom wall of the convex groove through an elastic metal sealing ring, and its rear surface is sealed and slidably connected to the front surface of the special steel sliding plate; the outer ring surface of the first sealing ring is sealed and fitted with the side wall of the feed channel, and its inner surface extends outwardly from the top of the inner ring surface of the second sealing ring to the front part of its outer ring surface, forming a tapered connection port connected to the feed channel; A first filling groove in an annular structure is provided at intervals on the rear surface of the first special steel sealing ring, and a graphite sealing ring is clamped in the first filling groove for sealing the special steel sliding plate and the first special steel sealing ring together to prevent the PVC melt from overflowing; The second sealing member is a second special steel sealing ring mounted on the top of the discharge channel, and a second filling groove in an annular structure is provided on the front surface thereof. The graphite sealing ring mounted in the second filling groove seals the special steel sliding plate and the second special steel sealing ring together to prevent the PVC melt from overflowing.

2. The PVC hot melt filter according to claim 1, characterized in that: The cross section of the elastic metal sealing ring is a V-shaped structure with the opening facing inwards.

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