Horizontal spiral discharging fine filtering centrifugal machine

Abstract

The utility model discloses a horizontal type spiral discharging fine filtering centrifugal machine which comprises a driver, an NC differential mechanism, a bearing seat, an outer shaft, an inner shaft, an outer cover shell, a rotary drum with filtering holes, a first annular plate, a spiral wheel drum with meshes, an inner barrel, a feeding pipe, a back flushing unit and a cleaning pipe. According to the utility model, when the feed quantity is suddenly too large, the feed which enters excessively is accommodated and is prevented from directly flowing out of the rotary drum to cause complete failure of filtration, and when the feed quantity is seriously too large, the gap between the rotary drum and the spiral wheel drum can be adjusted in a self-adaptive manner; and separation and filtration are carried out as far as possible while the feed does not directly flow into the discharge port.

Description

Technical Field

[0001] The utility model relates to the field of solid-liquid separation, in particular to a horizontal spiral unloading fine filtering centrifuge. Background Art

[0002] In the production process of polyphenylene sulfide, conventional filter centrifuges are prone to separate products with smaller particle sizes. At the same time, the filter is easily deformed or perforated by solid materials, which can easily lead to failure of dynamic balance of the equipment and leakage of more finished products. To solve this problem, a spiral unloading filter centrifuge was selected based on the original equipment. The spiral unloading filter centrifuge is a solid-liquid separation equipment that uses the filtering principle to separate suspensions. It can perform solid-liquid separation or centrifugal dehydration on small suspended particles and is equipped with a washing function. When working, the motor drives the drum and the concentrically installed feeding screw to rotate at a high speed in the same direction at a certain differential speed. The material is continuously collected by the feed and evenly distributed on the filter wall at the bottom of the drum. Under the action of centrifugal force, the liquid phase passes through the filter screen and the filter holes on the drum wall and is discharged from the drum. It is discharged from the machine through the discharge port. The solid phase is trapped in the drum to form filter residue. Under the combined action of the conical component of the centrifugal force and the feeding screw, the filter residue continuously moves to the large end of the drum and is discharged from the drum, and is discharged from the machine through the unloading trough.

[0003] The feed of the current spiral unloading filter centrifuge must be relatively stable. If there is a malfunction in the manual feed control or automatic feed control system, resulting in a sudden excessive feed volume, the feed will flow in and out of the drum, and the filtration will fail completely. Utility Model Content

[0004] In view of the above-mentioned defects of the prior art, the purpose of the utility model is to provide a horizontal spiral unloading fine filtering centrifuge. When the feed amount is suddenly too large, the excess feed entering can be accommodated and prevented from directly flowing out of the drum to cause complete filtration failure. When the feed amount is seriously excessive, the gap between the drum and the spiral wheel drum will be adaptively adjusted to ensure that the feed does not directly flow into the discharge port while performing separation and filtration as much as possible.

[0005] The purpose of the utility model is achieved through such technical solution:

[0006] A horizontal spiral unloading fine filtering centrifuge, comprising:

[0007] Driver;

[0008] NC differential, the input end is connected to the driver, and the driver drives the NC differential to rotate;

[0009] Bearing seat, connected to the NC differential housing;

[0010] An outer shaft is disposed in the bearing housing and connected to an output end of the NC differential;

[0011] The inner shaft and the inner sleeve are arranged inside the outer shaft and connected to the other output end of the NC differential;

[0012] The head of the outer cover shell is connected to the bearing seat, and the interior forms a closed space with the bearing seat; the outer shaft and the inner shaft are located in the closed space; a liquid outlet is provided below the head of the outer cover shell, and a material outlet is provided below the tail of the outer cover shell;

[0013] The drum with filtering holes is trumpet-shaped, and the head is coaxially connected to the outer shaft; the opening of the head is smaller than the opening of the tail;

[0014] The first ring plate is arranged in the outer casing and is located directly below the tail end of the drum; the liquid outlet is located between the first ring plate and the bearing seat; the material outlet is located between the first ring plate and the tail end of the outer casing;

[0015] The spiral drum with mesh is in the shape of a trumpet. The head is coaxially connected to the inner shaft through a telescopic reset unit and is located inside the drum. A spiral blade is provided on the outer surface. The minimum distance between the end of the spiral blade and the inner wall of the drum is no more than 1 mm. When the inner shaft rotates, the spiral blade rotates, driving the material between the spiral drum and the drum to move toward the tail of the outer casing.

[0016] The inner cylinder has a truncated cone-shaped outer contour, the diameter of the head end is larger than the tail end, and the head end of the rotating cylinder is coaxially connected to the spiral wheel drum;

[0017] A feed pipe, passing through the outer casing and entering the drum, with the end thereof being located in the inner cylinder;

[0018] A recoil unit is provided on the feed pipe to guide the feed to impact the inner cylinder in the reverse direction;

[0019] The cleaning pipe passes through the outer cover shell and enters the drum, and its liquid outlet is located behind the liquid outlet of the feed pipe.

[0020] Furthermore, the drum comprises:

[0021] A connecting plate, which is mounted on the inner shaft and fixedly connected to the outer shaft;

[0022] The outer contour of the rotating drum is in the shape of a truncated cone, and the diameter of the head end is smaller than that of the tail end; the head end of the rotating drum is coaxially connected with the connecting disk; and the spiral wheel drum is located in the rotating drum.

[0023] Furthermore, the rotary drum further comprises:

[0024] The positioning cylinder is in the shape of a round tube, with the same diameter as the tail end of the rotating cylinder, and is seamlessly connected to the tail end of the rotating cylinder;

[0025] The first bearing is sleeved on the outer surface of the positioning tube, and the outer surface is fixedly connected to the inner end surface of the first ring plate.

[0026] Furthermore, the spiral drum comprises:

[0027] The drum bottom is connected coaxially with the inner shaft;

[0028] The outer contour of the drum is a truncated cone, and the diameter of the head end is smaller than that of the tail end; the head end of the rotating drum is coaxially connected to the drum bottom; the spiral wheel drum is located in the rotating drum; the drum is provided with mesh holes; and the outer surface of the drum is provided with spiral blades.

[0029] Furthermore, the spiral drum further comprises:

[0030] The limiting cylinder is in the shape of a circular tube, has the same diameter as the tail end of the rotating cylinder, and is seamlessly connected to the tail end of the rotating cylinder;

[0031] A second bearing is sleeved on the outer surface of the limiting cylinder;

[0032] The second ring plate is sleeved on the second bearing and connected to the inner wall of the outer cover shell; the cavity surrounded by the first ring plate, the second ring plate and the outer cover shell of the limiting cylinder is communicated with the discharge port.

[0033] Furthermore, the discharge port is communicated with both sides of the second ring plate.

[0034] Furthermore, a drainage spiral is provided on the inner wall of the inner cylinder to guide the feed entering the drainage spiral to flow along the drainage spiral toward the bottom of the drum.

[0035] Furthermore, the inner shaft comprises:

[0036] The front axle, the front inner sleeve is set inside the outer shaft, connected to the other output end of the NC differential, and the rear end is provided with a spline groove;

[0037] The rear axle is rotatably sleeved in the outer axle, and the front end surface of the rear axle is provided with a spline column corresponding to the spline groove on the front axle; the tail of the rear axle is coaxially connected to the spiral wheel drum;

[0038] The telescopic reset unit comprises a spring, which is sleeved on the rear axle, and two ends of which are respectively connected with the outer shaft and the spiral wheel drum.

[0039] Furthermore, the recoil unit comprises:

[0040] A connecting frame connected to the feed pipe;

[0041] The recoil shield is connected to the connecting frame and is coaxially arranged on the axis of the feed pipe to guide the feed facing the recoil shield to obliquely rush toward the inner wall of the inner cylinder, so that the inner cylinder is subjected to a force toward the tail of the spiral wheel drum.

[0042] Furthermore, it also includes a guide tube with a trapezoidal outer contour, a head diameter larger than a tail diameter, which is arranged on the outside of the inner tube and seamlessly fixed to the inner wall of the drum; the outlet of the cleaning pipe is located between the inner tube and the outer tube.

[0043] Due to the adoption of the above technical solution, the utility model has the following advantages:

[0044] 1. The inner cylinder is used to accommodate the feed entering the feed pipe to a certain extent, so that the feed flows directly through the spiral drum and enters the discharge port, resulting in the feed not being separated and filtered.

[0045] 2. Through the recoil unit, when the incoming material volume is too large, the position of the spiral drum in the drum is adjusted in combination with the telescopic reset unit, and the gap difference between the spiral drum and the drum is adjusted to enhance the passability, so that the excess feed can be discharged through the gap difference between the spiral drum and the drum. The feed is also centrifugally separated to a certain extent in the gap between the spiral drum and the drum, avoiding the possibility of the feed entering the discharge port without being separated, and ensuring the quality of separation and filtration to a certain extent.

[0046] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and will be apparent to those skilled in the art based on the following examination and study, or may be taught from the practice of the present invention to some extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The accompanying drawings of the present utility model are as follows:

[0048] Figure 1 It is a schematic cross-sectional view of the horizontal spiral unloading fine filtering centrifuge in the embodiment.

[0049] Figure 2 for Figure 1 Enlarged structural diagram at A in the middle.

[0050] Figure 3 for Figure 1 Enlarged structural diagram at B in the middle.

[0051] Figure 4 for Figure 1 Enlarged structural diagram at point C in the middle.

[0052] Figure 5 for Figure 1 Enlarged structural diagram at D in the middle.

[0053] In the figure: 1. NC differential; 2. bearing seat; 3. outer shaft; 41. front shaft; 411. spline groove; 42. rear shaft; 421. spline column; 5. outer cover shell; 51. liquid outlet; 52. material outlet; 61. connecting plate; 62. rotating drum; 63. positioning cylinder; 64. first bearing; 7. first ring plate; 81. drum bottom; 82. drum; 821. spiral blade; 83. limiting cylinder; 84. second bearing; 85. second ring plate; 9. inner cylinder; 91. drainage spiral; 10. feed pipe; 111. connecting frame; 112. recoil cover; 12. cleaning pipe; 13. spring; 14. guide cylinder. DETAILED DESCRIPTION

[0054] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0055] Example:

[0056] like Figure 1-5 As shown, a horizontal spiral unloading fine filtering centrifuge comprises:

[0057] The drive can be a motor or a belt, etc.;

[0058] The input end of the NC differential 1 is connected to the driver, and the driver drives the NC differential 1 to rotate;

[0059] The bearing seat 2 is connected to the housing of the NC differential 1;

[0060] The outer shaft 3 is arranged in the bearing seat 2 and connected to an output end of the NC differential 1;

[0061] The inner shaft and the inner sleeve are arranged inside the outer shaft 3 and connected to the other output end of the NC differential 1;

[0062] The outer cover shell 5 has a head connected to the bearing seat 2, and the interior forms a closed space with the bearing seat 2; the outer shaft 3 and the inner shaft are located in the closed space; a liquid outlet 51 is provided under the head of the outer cover shell 5, and a material outlet 52 is provided under the tail of the outer cover shell 5; in this embodiment, the outer cover shell 5 is divided into two parts, which are convenient for maintenance and installation after opening.

[0063] The drum with filtering holes (not shown in the figure) is trumpet-shaped, and the head is coaxially connected to the outer shaft 3; the head opening is smaller than the tail opening;

[0064] The first ring plate 7 is arranged in the outer cover shell 5 and is located directly below the tail end of the drum; the liquid outlet 51 is located between the first ring plate 7 and the bearing seat 2; the material outlet 52 is located between the first ring plate 7 and the tail end of the outer cover shell 5;

[0065] The spiral drum with mesh (not shown in the figure) is horn-shaped, and its head is coaxially connected to the inner shaft through a telescopic reset unit, located inside the drum, and a spiral blade 821 is provided on the outer surface; the minimum distance between the end of the spiral blade 821 and the inner wall of the drum is no more than 1 mm; when the inner shaft rotates, the spiral blade 821 rotates, driving the material between the spiral drum and the drum to move toward the tail of the outer cover 5;

[0066] The inner cylinder 9 has a truncated cone outer contour, and the diameter of the head end is larger than the tail end. The head end of the rotating cylinder 62 is coaxially connected to the spiral drum.

[0067] The feed pipe 10 passes through the outer casing 5 and enters the drum, and the end thereof is located in the inner cylinder 9;

[0068] A recoil unit is provided on the feed pipe 10 to guide the feed to impact the inner cylinder 9 in the reverse direction;

[0069] The cleaning pipe 12 passes through the outer casing 5 and enters the drum, and its liquid outlet is located behind the liquid outlet 51 of the feed pipe 10.

[0070] The inner cylinder 9 is provided to accommodate the feed entering through the feed pipe 10 to a certain extent, so that the feed is directly discharged through the spiral drum and enters the discharge port 52, resulting in the feed not being separated and filtered.

[0071] By setting the recoil unit, when the incoming material volume is too large, the position of the spiral drum in the drum is adjusted in combination with the telescopic reset unit, and the gap difference between the spiral drum and the drum is adjusted to enhance the passability, so that the excess feed can be discharged through the gap difference between the spiral drum and the drum. The feed is also centrifugally separated to a certain extent in the gap between the spiral drum and the drum, avoiding the possibility of the feed entering the discharge port 52 without being separated, and ensuring the quality of separation and filtration to a certain extent.

[0072] In this embodiment, the drum comprises:

[0073] A connecting plate 61, which is covered with the inner shaft and fixedly connected with the outer shaft 3;

[0074] The outer contour of the rotating drum 62 is in the shape of a truncated cone, and the diameter of the head end is smaller than that of the tail end; the head end of the rotating drum 62 is coaxially connected to the connecting disk 61; and the spiral wheel drum is located inside the rotating drum 62.

[0075] The connection plate 61 facilitates installation and can better transmit force to the rotating drum 62.

[0076] In this embodiment, the rotary drum further comprises:

[0077] The positioning cylinder 63 is in the shape of a circular tube, has the same diameter as the rear end of the rotating cylinder 62, and is seamlessly connected to the rear end of the rotating cylinder 62;

[0078] The first bearing 64 is sleeved on the outer surface of the positioning tube 63 , and the outer surface is fixedly connected to the inner end surface of the first ring plate 7 .

[0079] The tail of the rotating drum 62 can be limited by the positioning cylinder 63, the first bearing 64 and the first ring plate 7 to prevent it from shaking.

[0080] In this embodiment, the spiral drum comprises:

[0081] The drum bottom 81 is coaxially connected to the inner shaft;

[0082] The outer contour of the drum 82 is a truncated cone, and the diameter of the head end is smaller than the tail end; the head end of the rotating drum 62 is coaxially connected to the drum bottom 81; the spiral wheel drum is located inside the rotating drum 62; the drum 82 is provided with mesh holes (not shown in the figure); the outer surface of the drum 82 is provided with spiral blades 821.

[0083] The spiral drum also includes:

[0084] The limiting cylinder 83 is in the shape of a circular tube, has the same diameter as the rear end of the rotating cylinder 62, and is seamlessly connected to the rear end of the rotating cylinder 62;

[0085] The second bearing 84 is sleeved on the outer surface of the limiting cylinder 83;

[0086] The second ring plate 85 is sleeved on the second bearing 84 and connected to the inner wall of the outer casing 5 ; the cavity surrounded by the first ring plate 7 , the second ring plate 85 , the limiting tube 83 and the outer casing 5 is communicated with the discharge port 52 .

[0087] The tail of the drum 82 is limited by the limiting cylinder 83 , the second bearing 84 and the second ring plate 85 to prevent it from shaking, and at the same time, the discharge is restricted so that all the discharged materials enter the discharge port 52 .

[0088] In this embodiment, the discharge port 52 is communicated with two sides of the second ring plate 85 .

[0089] When the feed amount far exceeds the designed amount of the product, the feed flows out from the end of the spiral drum and finally can smoothly flow out through the discharge port 52 without being accumulated in the outer cover shell 5.

[0090] In this embodiment, a drainage spiral 91 is provided on the inner wall of the inner cylinder 9 to guide the feed entering the drainage spiral 91 to flow along the drainage spiral 91 toward the drum bottom 81 .

[0091] The drainage spiral 91 can evenly distribute the feed accumulated in the inner cylinder 9 into the inner cylinder 9 under the action of rotating centrifugal force, thereby increasing the capacity of the inner cylinder 9 and improving the ability to cope with a sudden increase in feed.

[0092] In this embodiment, the inner shaft includes:

[0093] The front shaft 41, the front inner sleeve is arranged inside the outer shaft 3, connected to the other output end of the NC differential 1, and the rear end is provided with a spline groove 411;

[0094] The rear shaft 42 is rotatably sleeved in the outer shaft 3, and the front end surface of the rear shaft 42 is provided with a spline column 421 corresponding to the spline groove 411 on the front shaft 41; the tail of the rear shaft 42 is coaxially connected to the spiral wheel drum;

[0095] The telescopic reset unit comprises a spring 13 which is sleeved on the rear shaft 42 and has two ends connected to the outer shaft 3 and the spiral drum respectively.

[0096] The telescopic connection is achieved by a spline connection, and the telescopic reset is achieved by a spring 13.

[0097] In this embodiment, the recoil unit includes:

[0098] A connecting frame 111 is connected to the feed pipe 10;

[0099] The recoil cover 112 is connected to the connecting frame 111 and is coaxially arranged on the axis of the feed pipe 10 to guide the feed facing the recoil cover 112 to obliquely rush toward the inner wall of the inner cylinder 9, so that the inner cylinder 9 is subjected to a force toward the tail of the spiral drum.

[0100] In this embodiment, a guide tube 14 is also included, the outer contour of which is trapezoidal, the head diameter is larger than the tail diameter, and it is arranged on the outside of the inner tube 9 and seamlessly fixed to the inner wall of the drum 82; the outlet of the cleaning pipe 12 is located between the inner tube 9 and the outer tube.

[0101] The guide cylinder 14 can limit the incoming cleaning water to a specific range, thereby improving the quality and effect of cleaning, that is, ensuring that all the discharged materials passing through the specific range are cleaned.

[0102] The horizontal spiral unloading fine filtering centrifuge of this embodiment works as follows: the equipment is started, feed is injected into the feed pipe 10, and cleaning water is injected into the cleaning pipe 12.

[0103] The feed material impacts the recoil shield 112, flows to the inner cylinder 9, and flows on the drainage spiral 91 as the inner cylinder 9 rotates. While guiding the flow of the feed material, the feed material is also subjected to centrifugal force and centrifugally separated to a certain extent. Then, it enters the rotating drum through the drum 82, and is centrifugally separated during the rotation of the rotating drum. The liquid passes through the rotating drum 62 and flows out from the liquid outlet 51. The solid-liquid or liquid containing more solids continues to move rightward as the spiral blade 821 rotates and the centrifugal force separates rightward, and is continuously centrifugally filtered.

[0104] As the filtered material continues to move, it arrives at the area of ​​the cleaning pipe 12, mixes with the cleaning water, and is cleaned. Finally, the filtering and separation is continued until it is discharged through the discharge port 52 after the filtering is completed.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the utility model.

Claims

1. A horizontal spiral unloading fine filtering centrifuge, characterized in that: include: Driver; NC differential, the input end is connected to the driver, and the driver drives the NC differential to rotate; Bearing seat, connected to the NC differential housing; An outer shaft is disposed in the bearing housing and connected to an output end of the NC differential; The inner shaft and the inner sleeve are arranged inside the outer shaft and connected with the other output end of the NC differential; The head of the outer cover shell is connected to the bearing seat, and the interior forms a closed space with the bearing seat; the outer shaft and the inner shaft are located in the closed space; a liquid outlet is provided below the head of the outer cover shell, and a material outlet is provided below the tail of the outer cover shell; The drum with filtering holes is trumpet-shaped, and the head is coaxially connected to the outer shaft; the opening of the head is smaller than the opening of the tail; The first ring plate is arranged in the outer casing and is located directly below the tail end of the drum; the liquid outlet is located between the first ring plate and the bearing seat; the material outlet is located between the first ring plate and the tail end of the outer casing; The spiral drum with mesh is in the shape of a trumpet. The head is coaxially connected to the inner shaft through a telescopic reset unit and is located inside the drum. A spiral blade is provided on the outer surface. The minimum distance between the end of the spiral blade and the inner wall of the drum is no more than 1 mm. When the inner shaft rotates, the spiral blade rotates, driving the material between the spiral drum and the drum to move toward the tail of the outer casing. The inner cylinder has a truncated cone-shaped outer contour, the diameter of the head end is larger than the tail end, and the head end of the rotating cylinder is coaxially connected to the spiral wheel drum; A feed pipe, passing through the outer casing and entering the drum, with the end thereof being located in the inner cylinder; A recoil unit is provided on the feed pipe to guide the feed to impact the inner cylinder in the reverse direction; The cleaning pipe passes through the outer cover shell and enters the drum, and its liquid outlet is located behind the liquid outlet of the feed pipe.

2. The horizontal spiral unloading fine filtering centrifuge according to claim 1 is characterized in that: The rotary drum comprises: A connecting plate, which is mounted on the inner shaft and fixedly connected to the outer shaft; The outer contour of the rotating drum is in the shape of a truncated cone, and the diameter of the head end is smaller than that of the tail end; the head end of the rotating drum is coaxially connected with the connecting disk; and the spiral wheel drum is located in the rotating drum.

3. The horizontal spiral unloading fine filtering centrifuge according to claim 2 is characterized in that: The rotary drum also includes: The positioning cylinder is in the shape of a round tube, with the same diameter as the tail end of the rotating cylinder, and is seamlessly connected to the tail end of the rotating cylinder; The first bearing is sleeved on the outer surface of the positioning tube, and the outer surface is fixedly connected to the inner end surface of the first ring plate.

4. The horizontal spiral unloading fine filtering centrifuge according to claim 1, characterized in that: The spiral drum comprises: The drum bottom is connected coaxially with the inner shaft; The outer contour of the drum is a truncated cone, and the diameter of the head end is smaller than that of the tail end; the head end of the rotating drum is coaxially connected to the drum bottom; the spiral wheel drum is located in the rotating drum; the drum is provided with mesh holes; and the outer surface of the drum is provided with spiral blades.

5. The horizontal spiral unloading fine filtering centrifuge according to claim 4 is characterized in that: The spiral drum also includes: The limiting cylinder is in the shape of a circular tube, has the same diameter as the tail end of the rotating cylinder, and is seamlessly connected to the tail end of the rotating cylinder; A second bearing is sleeved on the outer surface of the limiting cylinder; The second ring plate is sleeved on the second bearing and connected to the inner wall of the outer cover shell; the cavity surrounded by the first ring plate, the second ring plate and the outer cover shell of the limiting cylinder is communicated with the discharge port.

6. The horizontal spiral unloading fine filtering centrifuge according to claim 5, characterized in that: The discharge port is communicated with both sides of the second ring plate.

7. The horizontal spiral unloading fine filtering centrifuge according to claim 4, characterized in that: The inner wall of the inner cylinder is provided with a drainage spiral to guide the feed entering the drainage spiral to flow along the drainage spiral toward the bottom of the drum.

8. The horizontal spiral unloading fine filtering centrifuge according to claim 7, characterized in that: The inner shaft comprises: The front axle, the front inner sleeve is set inside the outer shaft, connected to the other output end of the NC differential, and the rear end is provided with a spline groove; The rear axle is rotatably sleeved in the outer axle, and the front end surface of the rear axle is provided with a spline column corresponding to the spline groove on the front axle; the tail of the rear axle is coaxially connected to the spiral wheel drum; The telescopic reset unit comprises a spring, which is sleeved on the rear axle, and two ends of which are respectively connected with the outer shaft and the spiral wheel drum.

9. The horizontal spiral unloading fine filtering centrifuge according to claim 4, characterized in that: The recoil unit comprises: A connecting frame connected to the feed pipe; The recoil shield is connected to the connecting frame and is coaxially arranged on the axis of the feed pipe to guide the feed facing the recoil shield to obliquely rush toward the inner wall of the inner cylinder, so that the inner cylinder is subjected to a force toward the tail of the spiral wheel drum.

10. The horizontal spiral unloading fine filtering centrifuge according to claim 4, characterized in that: It also includes a guide tube with a trapezoidal outer contour, a head diameter larger than a tail diameter, which is arranged on the outside of the inner tube and seamlessly fixed to the inner wall of the drum; the outlet of the cleaning pipe is located between the inner tube and the outer tube.

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