JPH11241700A - Spiral flow generating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate a more stable spiral flow within a pipe line and to facilitate design and adjustment therefor. SOLUTION: This device is a device generating a spiral flow in a pipe line in which the other end of a main cylinder 1 connected with the pipe line is connected with an auxiliary cylinder 2 with non-connection tip part opened to the outside or connected with a separate pipe line via a ring slit 3; a wall surface on the side of the main cylinder of the ring slit 3 is smoothly curved and transfers to an inner wall 11 of the main cylinder 1; a wall surface on the side of the auxiliary cylinder 2 of the ring slit 3 bends and transfers to an inner wall 21 of the auxiliary cylinder 2; the diameter of the inner wall 11 of the main cylinder 1 has a conical part which gradually reduces in a pipe line connecting direction; and a means supplying pressurized fluid is provided at the outside of the ring slit 3. In this case, an inner diameter of the ring slit 3 as Dc, flow velocity of fluid passing through the ring slit 3 as (u), an angle formed by a fluid jetting direction from the ring slit 3 and a revolving shaft as α and a kinematic viscosity of fluid as νare defined, (Dc.u.sinα)/ν is defined as a ring slit Reynolds number and this value is defined as a range of 150,000 to 7,500,000.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for generating a spiral flow in a pipeline.
More specifically, the invention of this application relates to an apparatus for generating a spiral flow in a pipe, which is useful for purposes such as pipe transport, drying, surface modification, mixing, or dispersion.

[0002]

2. Description of the Related Art A pipeline transport system using a compressed fluid has been used for various purposes because of its advantages such as the ability to transport by pipeline and the scatter of transported objects. However, in these conventional methods of transporting pipelines using compressed fluid, the transported object collides with or comes into contact with the pipe wall. In the case of the conveyed object, there was a drawback that the conveyed object was crushed, and the inventors of the present application attempted to solve such a drawback by using a conventional fluid transport method. We have been working to develop a completely new technology that is fundamentally different.
As a result, the present inventors have, for example,
No. 640, “A device for generating a spiral fluid in a pipeline”,
As described in Patent Registration No. 2506080 "Method of transporting solid particles", a cone portion having an annular slit and a curved surface on which a Coanda effect is generated enables the passage in a pipeline without particularly giving a swirl component. A spiral flow (spiral air flow) is generated, and solid particles are supplied to the spiral air flow area, so that the solid particles are transported in the pipe while spirally moving without contacting the pipe wall. The means for that are proposed.

The spiral flow as a feature of this transportation method shows a very interesting behavior, and its application field is also described, for example, in Japanese Patent Publication No. Hei 7-44469, "Method of penetrating electric wires and cables and its apparatus". Japanese Patent Publication No. Hei 8-11625, "Fibrillation and Conveying Method of Agglomerated Short Fibers", Japanese Patent Publication No. Hei 8-201779, "Method and Apparatus for Drying Granular Materials", Patent Registration No. 2048579, "Coanda Spiral Reactor" Japanese Patent Application Laid-Open No. 60-34269, "Blowing method by spiral airflow", Japanese Patent Application Laid-Open No. 60-515
No. 28, "Method of Separating Mixed Gas by Spiral Airflow", JP-A-60-51581, "Method of Separating Lumps", JP-A-60-53792, "Method of Heat Separation by Spiral Airflow", As exemplified in Japanese Unexamined Patent Publication No. Hei. It is expected that its use will be expanded and its application range will be expanded.

[0004] Further, with respect to an apparatus for generating such a spiral flow in a pipeline, for example, Japanese Patent Publication No. 8-6720, "Method and Apparatus for Controlling Coanda Spiral Flow" and Japanese Patent Publication No. 6-60640. In the publication “Apparatus for Generating Spiral Fluid in Pipeline” and the like, specific proposals are made regarding the shape and dimensions of each section of the generating apparatus and the necessity of accessory parts.

[0005]

However, in the subsequent studies by the inventors of the present application, it has become clear that there is a need for further improvement in the generation of spiral flow and its application. This is because, for example, regarding the shape of each part, for example, the ratio of the pipe diameter to the transported solid particles, the width of the annular gap (annular slit width) at the connection between the main cylinder and the auxiliary cylinder, and the cone part This is because, although the guideline for the diameter reduction ratio and the like has been obtained, more general guidelines for defining them and setting of a range based on the guidelines have not always been sufficiently investigated. For this reason, as a result, in setting these values, there is a face that it is necessary to rely on experience.

For example, the width of the annular gap and the squeezing rate of the cone diameter are very important factors for stably generating a spiral flow. As a result, the stability has been reduced due to changes in the flow rate and the supply flow rate, and control for stabilization has not always been easy. For this reason, in some cases, the design of the device for generating the spiral flow has to be changed.

The invention of this application has been made in order to solve the above-described problems, and has established a guideline for stably generating a spiral flow and facilitating design and control for the spiral flow. An object of the present invention is to provide a spiral flow generation device based on a new concept, which facilitates the design and adjustment of the spiral flow generation device and further expands the engineering application of the spiral flow.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides, as a first invention, a structure in which a non-connection end is connected to the other end of a main cylinder connected to a pipeline. The auxiliary cylinder connected to another pipe line is connected through an annular gap, and the wall surface of the annular gap on the main cylinder side smoothly curves and transitions to the inner wall of the main cylinder, and the annular gap is closed. The wall surface on the auxiliary cylinder side is bent and transitions to the inner wall of the auxiliary cylinder, has a cone portion in which the inner wall diameter of the main cylinder gradually decreases in the pipe connection direction, and supplies pressurized fluid to the outside of the annular slit. Wherein the inner diameter of the annular gap is D _c , the flow velocity of the fluid passing through the annular gap is u, the direction of fluid ejection from the annular gap and the axis of rotation. Α and the kinematic viscosity coefficient of the fluid as ν, (D _c · u · s
inα) / ν is defined as the annular slit Reynolds number,
A spiral flow generation device is provided, wherein this value is in the range of 150,000 to 7,500,000.

In this application, a second aspect of the present invention relates to a spiral flow generating device in which the squeezing rate of the inner diameter of the cone portion is 0.55 to 0.85 as a second invention. A fourth aspect of the present invention is a spiral flow generating device provided with a pipeline connection portion which is expanded from the inner diameter of the cone small diameter portion smaller than the inner diameter of the pipeline to the inner diameter of the pipeline with a taper of 5 to 30 degrees. As a fifth aspect of the present invention, a spiral flow generation device having a structure in which the width of an annular gap in a connection portion between a main cylinder and an auxiliary cylinder can be arbitrarily adjusted is more specifically described. The present invention also provides a spiral flow generating device having a structure in which the width of the annular slit can be arbitrarily adjusted by exchanging different liners.

In this application, as a sixth invention, a spiral flow generating apparatus for supplying a conveyed object from the outside of the auxiliary cylinder in the axial direction of the main cylinder is specifically described as a seventh invention. For example, a spiral flow generating device having a structure in which a conveyed object supply pipe is inserted into an auxiliary cylinder and a tip position of the conveyed object supply pipe is arbitrarily adjusted is further provided in the eighth invention. The present invention also provides a spiral flow generation device in which a main cylinder and an annular gap forming portion of an auxiliary cylinder are detachable.

[0011] As described above, in the present application, as the invention as described above, in the apparatus for easily and stably generating the spiral flow, the width of the annular gap is designed,
Introducing the annular slit Reynolds number, which serves as a guideline for adjustment, clarifying the range and squeezing ratio of the inner diameter of the cone, and setting the device that newly connects the attached pipe to the main cylinder and the annular gap width There are significant features in providing the structure.

As a result of detailed studies by the present inventors, if the viscosity of the annular jet is neglected, the momentum of the invention in the present invention as described above varies between the radial, swirling and axial directions in the spiral flow generating device. More specifically, in the generator, the momentum in the axial direction hardly changes, the momentum in the radial direction decreases, and the momentum in the turning direction increases. Has been completed by further deepening.

More specifically, first, it is considered that the turning component of the spiral flow is generated by converting the speed component in the radial direction into the speed component in the turning direction. Therefore, regarding the stability of the spiral flow, It is presumed that the larger the initial velocity component in the radial direction, the larger the spiral flow with a large turning velocity component, and the more stable the spiral flow with a long vortex.

On the other hand, not all of the initial radial velocity components are converted into turning velocity components, and the remaining radial components that have not been converted collide at the central axis and cause turbulence in the flow. Is considered to contribute to disrupting the spiral flow. Then, the initial radial momentum to obtain a stable spiral flow should have a certain range.

Accordingly, the inventor of the present application proposes that the Reynolds number of the fluid in the radial direction when passing through the annular gap, that is, Res = (D _C u u sin α) / ν, where D _C : inner diameter of the annular gap u: average flow velocity of the fluid when passing through the annular gap α: angle between the fluid ejection direction of the annular gap and the pivot axis ν: annular slit Reynolds number (Res) expressed by the kinematic viscosity coefficient of the fluid A dimension was introduced to represent the momentum in the radial direction.

Then, the annular slit Reynolds number (Res) was taken as a factor for determining the annular gap width, and the relationship with the spiral flow stability was verified in various spiral flow generators. As a result, it has been found that the most stable spiral flow is obtained when the annular slit Reynolds number (Res) takes a value within a certain range, that is, a value of 150,000 to 7,500,000.

Furthermore, it has been found that, for stabilizing the spiral flow, the degree of swirl is somewhat sacrificed, but the squeezing rate of the cone diameter is preferably set to 0.55 to 0.85. . Annular slit Reynolds number (Res)
Are as shown in Table 1 below, for example. Table 1 shows that 21 of A to U in which the values of the respective parts are different.
For various types of spiral flow generators, the relationship between operating conditions, annular slit Reynolds number (Res), and spiral flow stability is shown.

[0018]

[Table 1]

In the basic configuration of the spiral flow generating device in this case, as illustrated in FIG. 1, the other end of the main cylinder (1) connected to the pipe (9) has an annular slit (annular slit). The auxiliary cylinder (2) is connected via (3).
The inner wall of the main cylinder (1) forms a cone portion whose inner diameter is gradually reduced in the direction of the pipe (9). In this basic configuration, one of the auxiliary cylinders (2) is open, the annular slit (annular slit) (3) has a width (W), and a fluid, for example, compressed air is ejected in the pipe direction. It is designed to be ejected at an angle (α). Spout angle in this case (α)
Means the intersection angle between the extension of the straight portion of the annular slit (3) and the center line of the generator. The appropriate range is 7-9
0 °, more preferably 15 ° to 60 °.

The fluid flow rate in Table 1 indicates the flow rate of the fluid ejected from the annular gap (3) per unit time (minute). Further, the flow velocity (u) is calculated by the flow rate / D _C π · W. The squeezing rate is expressed as a ratio (D _S / D _L ) between the maximum inner diameter (D _L ) and the minimum inner diameter (D _S ) of the cone portion of the main cylinder (1). The squeezing rate is 0.38 to 0.667, and the generation stability of the spiral flow is evaluated.

Although there is a correlation with the squeezing rate, as shown in Table 1, for the stability of the spiral flow, there are three requirements, namely, the suppression of the backflow, the effect of eliminating from the wall surface, and the pressure loss. Judgment is made, and all three requirements are satisfied: excellent Two requirements are satisfied: good One requirement excluding pressure loss is satisfied: acceptable None is satisfied, or only pressure loss is satisfied: evaluation result is obtained. This means that the value of the annular slit Reynolds number (Res) is about 390,00
Excellent at 0 to 2,700,000, 280,000 to 78
0,000 is good, 160,000-200,000 and 5,500,000 are acceptable, 80,000 or less and 10,000
The result is unacceptable above 00,000. Therefore, R
The value of es is effective in the range of 150,000 to 7,500,000, more preferably 300,000 to
It is in the range of 3,000,000.

As described above, the spiral flow generator is designed so that the annular slit Reynolds number (Res) is required, and can be adjusted in the production thereof, so that the spiral flow generator is more stable than the conventional one. A flow can be generated.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a spiral flow generating device which is the basis of an embodiment of the present invention includes, as shown in FIG. 1, another end of a main cylinder (1) connected to a pipe (9);
That is, in FIG. 1, an annular slit (annular slit) is provided at the right end.
The auxiliary cylinder (2) is connected via (3), and the wall surface (31) of the annular narrow gap (3) on the main cylinder (1) side smoothly curves and shifts to the inner wall (11) of the main cylinder. The wall surface (32) of the annular slit (3) on the auxiliary cylinder (2) side is bent and the auxiliary cylinder (2) is bent.
The main cylinder (1) is formed so as to transition to the inner wall (21) of the main cylinder (1).
The inner wall may have a structure in which the diameter is gradually reduced to form a cone.

The main cylinder (1) may be formed in a cone shape immediately from the annular slit side as shown in FIG. 1 or FIG. 2, or may be formed from the annular slit side as shown in FIG. 3 or FIG. It may be formed in a cone shape through the cylindrical portion (12).
In any case, the annular slit Reynolds number (Res) represented by the above equation is 150,000 to
7,500,000, more preferably 300,000 to
To be in the range of 3,000,000, in relation to the flow velocity of the fluid passing through the annular slit (u) and dynamic viscosity of the fluid (ν), D _C: inner diameter of the annular slit and, W: The width α of the annular slit is designed so that the ejection angle of the fluid can be adjusted, and more preferably, it can be adjusted.

The squeezing rate of the cone part (D _S / D _L )
In the range of 0.55 to 0.85. As for the wall surface (32) on the auxiliary cylinder side of the annular gap, the auxiliary cylinder (2) may be formed in an open cone shape as shown in FIG. In addition, the wall surface (32) of the annular slit on the auxiliary cylinder side
Alternatively, as shown in FIG. 5, the auxiliary cylinder (2) may be formed in a conical shape with a concave outside.

A wall surface (32) on the auxiliary cylinder side of the annular gap (3)
6 to 9 are enlarged views of the annular narrow portion when the is bent and shifts to the inner wall (21) of the auxiliary cylinder (2). In FIG. 6, the wall surface (3
At a position where 1) has smoothly curved and transferred to the inner wall (11) of the main cylinder, that is, a position corresponding to the inner wall surface of the main cylinder,
The wall surface (32) of the annular slit (3) on the auxiliary cylinder (2) side is formed so as to be bent and transition to the inner wall (21) of the auxiliary cylinder (2). Wall surface (31)
At the position where the is smoothly curved and starts to move to the inner wall (11) of the main cylinder, that is, the position corresponding to the point A in the figure, the wall surface (32) of the annular gap (3) on the auxiliary cylinder (2) side is bent. In FIG. 8, the wall surface (31) of the annular narrow gap on the main cylinder side is smoothly curved and shifts to the inner wall (11) of the main cylinder. At a position before the starting position, that is, at a position corresponding to the point B in the figure, the wall surface (32) of the annular gap (3) on the auxiliary cylinder (2) side is bent to form an inner wall (21) of the auxiliary cylinder (2). The case where it is formed so as to shift is shown.

The annular gap (3) may be substantially vertical as shown in FIG. 9 without being inclined toward the main cylinder (1) as shown in FIGS. In the spiral flow generation device as described above, in order to generate a stable spiral flow, as described above, the annular slit Reynolds number relating to the width of the annular gap (3) at the connection between the main cylinder and the auxiliary cylinder ( Res) and the number is 150,
000 to 7,500,000, and more preferably 300,000 to 3,000,000.
000.

The squeezing rate at the cone portion,
Min. Inner diameter D of cone_SAnd maximum inner diameter D_LIs the ratio
0.55 to 0.85. That is, the cross-sectional area ratio is 0.
30 to 0.72. And this invention
In FIG. 10, as shown in FIG.
(D _S) Is the inside diameter (D_P) Smaller diameter,
And the inner diameter of the pipe connection portion (44) of the main cylinder is the cone small diameter portion.
Inner diameter (D_S) To the inner diameter of the pipe (9) (D_P5)
By enlarging with a taper of 30 degrees, a kind of ezez
Back pressure due to pressure loss in the connecting pipe line
Can be reduced.

Further, in the present invention, in order to select the width (W) of the annular slit so as to minimize the energy consumption and satisfy various purposes such as non-destructive conveyance and homogeneous mixing, the width (W) is selected. ) Is preferably a structure that can be adjusted arbitrarily. As a specific structure, for example, as shown in FIGS. 1, 3 and 4, an outer cylinder (4) directly connected to the main cylinder (1) and an auxiliary cylinder (2) are adjusted by a screw structure (41). 10, a liner (42) may be inserted between the main cylinder (1) and the auxiliary cylinder (2), and fixed by tightening with a screw or the like. .

Further, in the present invention, when the fluid involved in the spiral flow is air, the outside of the auxiliary cylinder, that is, the side opposite to the annular slit, is air as shown in FIG. 1, FIG. 3 or FIG. However, when the fluid is another fluid such as a liquid or a slurry, the fluid is closed with a bottom plate (22) as shown in FIG. It may be introduced from.

The shape of the cone portion may be, for example, a truncated cone shape as shown in FIGS. 1 to 4, but it is more preferable that the shape gives a smooth streamline. In addition, as shown in FIG. 10, the cone portion and the portion (43) of the auxiliary cylinder forming the annular gap may be detachable so as to be changed according to various purposes. As means for supplying the pressurized fluid to the outside of the annular slit, any suitable means can be adopted. For example, as shown in FIGS. 1 to 4 and FIG. A pressurized fluid distribution chamber (6) is provided by utilizing a gap between the inner wall of the outer cylinder (4) directly connected to (1) and the outer wall of the main cylinder 1, and an annular thin section is provided from the pressurized fluid distribution chamber (6). What is necessary is just to make it communicate with the outside of the space | gap (3) by the communication port (61). When fluid is fed into the distribution chamber (6) from the outside through the pressurized fluid supply pipe (7), the pressurized fluid is uniformly supplied to the outside of the annular gap (3) through the communication port (61). become.

Alternatively, as shown in FIG. 5, a pressurized fluid distribution chamber (6) formed in a hollow donut shape may directly contact the outside of the annular slit. When this spiral flow generator is used to convey solid particles and other conveyed substances in a pipeline, external fluid is sucked in at the auxiliary cylinder inlet, so that the conveyed substances are light and fine particles. In the case of (1), it is sucked together with the external fluid simply by supplying it to the vicinity of the auxiliary cylinder inlet, and is conveyed in the pipe direction.

As shown in FIGS. 2 and 4, from the viewpoint of controlling the transport amount and preventing dust, the auxiliary cylinder (2)
It is also effective to insert another pipeline, that is, a transported object supply pipe (8) from the outside of the main tube (1) in the axial direction of the main cylinder (1) and supply the transported object through this pipe. In this case, it is desirable that the position of the distal end of the supply pipe can be arbitrarily adjusted according to various purposes.

As means for supplying solid particles and the like through the conveyed object supply pipe (8), any known means such as a screw conveyor, a vibrating feeder, and high-density transportation by compressed air can be used. In the apparatus of the present invention, the pressurized fluid for generating the spiral flow may be of various types, and may be a gas, a liquid, or an arbitrary mixture thereof. Also, the transported object may be a gas, a liquid, or various solids such as a powder or a granular body.

[0035]

EXAMPLE The spiral flow generating device shown in FIG. 10 was connected to a 3-inch conduit including a vertical rising portion of 15 m, and the width of the annular slit was adjusted to an annular slit Reynolds number of about 1,000,000. It was set to become. About 1.5 kg / cm ² of compressed air was supplied from the pressurized fluid supply port (7).

A phenol resin (with a specific gravity of about 1. 1) is applied to the hopper only by applying a weak pressure of about 0.3 kg / cm ² .
3) could be supplied to the conveyed object supply pipe, and 3 t / hr of phenolic resin could be sent without crushing. This result also corresponds to “R” in Table 1 above. Observation of the telescope in the middle of the conduit showed that the phenolic resin was rising while turning, which was thought to be due to collision with the pipe wall during transport compared to general low-density transport. The generation of dust was also small.

[0037]

As described in detail above, the invention of this application makes it possible to easily generate a stable spiral flow in a pipeline. Therefore, even if the various transport conditions are different, the solid particles can be transported without coming into contact with the pipe wall, and by simple replacement of parts, it can be applied to application fields such as drying, surface modification, mixing, and dispersion. Can also respond.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of the device structure of the present invention.

FIG. 2 is a cross-sectional view showing an example in which a conveyed object supply pipe for supplying a granular material or the like is provided in an apparatus of the type illustrated in FIG.

FIG. 3 is a sectional view showing another example of the device structure of the present invention.

FIG. 4 is a cross-sectional view showing an example in which a conveyed object supply pipe for supplying a granular material or the like is provided in an apparatus of the type illustrated in FIG. 3;

FIG. 5 is a cross-sectional view illustrating the device of the present invention used as a booster in the middle of a pipeline.

FIG. 6 is a partially enlarged cross-sectional view illustrating a structure near an annular slit in the device of the present invention.

FIG. 7 is a partially enlarged cross-sectional view illustrating another structure near the annular slit in the device of the present invention.

FIG. 8 is a partially enlarged cross-sectional view illustrating still another structure near the annular slit in the device of the present invention.

FIG. 9 is a partially enlarged cross-sectional view illustrating another structure near the annular slit in the device of the present invention.

FIG. 10 is a sectional view showing still another example of the structure of the device of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Main cylinder 2 Auxiliary cylinder 3 Annular gap 4 Outer cylinder 5 Secondary fluid introduction pipe 6 Pressurized fluid distribution chamber 7 Pressurized fluid supply chamber 8 Conveyed object supply pipe 9 Pipeline 11 Inner wall of main cylinder 12 Cylindrical part 21 Auxiliary Inner wall of cylinder 22 Bottom plate 31 Main cylinder side wall surface of annular gap 32 Auxiliary cylinder side wall surface of annular gap 41 Screw structure 42 Liner 43 Part forming cone and annular slit of auxiliary cylinder DC _C the inner diameter D _S cone portion minimum inner diameter D _L maximum inner diameter D _P pipe inner diameter 44 conduit connection section 61 communication port of the cone of the

Claims (8)

[Claims] 1. The other end of a main cylinder connected to a pipe,
An auxiliary cylinder whose non-connection end is open to the outside or connected to another pipeline is connected via an annular gap, and the wall surface of the annular cylinder on the main cylinder side is smoothly curved to form the main cylinder. Transition to the inner wall, the wall surface of the annular gap on the auxiliary cylinder side bends and transitions to the inner wall of the auxiliary cylinder, and has a cone portion in which the inner wall diameter of the main cylinder gradually decreases in the pipe connection direction, and An apparatus for generating a spiral flow in a pipe provided with a means for supplying a pressurized fluid to the outside, wherein the inner diameter of the annular gap is D _c , the flow rate of the fluid passing through the annular gap is u, the angle between the fluid ejection direction and the pivot axis alpha, when the dynamic viscosity of the fluid was [nu _{of, (D c · u · sinα} ) / ν is defined an annular slit Reynolds number, the value is 150,000 ~ 7,
A spiral flow generator, wherein the range is 500,000. 2. The squeezing rate of the inner diameter of the cone portion is 0.55 to 0.55.
The spiral flow generator according to claim 1, wherein the value is 0.85. 3. The connecting portion of the main cylinder to the pipe line has a diameter ranging from the inner diameter of the small cone portion smaller than the inner diameter of the pipe line to the inner diameter of the pipe line.
The spiral flow generating device according to claim 1 or 2, further comprising a pipeline connection portion enlarged by a taper of up to 30 degrees. 4. The spiral flow generator according to claim 1, wherein the width of the annular gap at the connection between the main cylinder and the auxiliary cylinder is adjustable. 5. The spiral flow generating device according to claim 4, wherein the width of the annular narrow space at the connecting portion between the main cylinder and the auxiliary cylinder can be arbitrarily adjusted by exchanging liners having different thicknesses. 6. The spiral flow generating device according to claim 1, wherein a conveyed object is supplied from outside the auxiliary cylinder toward the axial direction of the main cylinder. 7. A conveyed object supply pipe for supplying a conveyed object from the outside of the auxiliary cylinder toward the axial direction of the main cylinder is inserted into the auxiliary cylinder, and a tip position of the conveyed object supply pipe is arbitrary. 7. The spiral flow generating device according to claim 6, wherein the spiral flow generating device is configured to be adjustable. 8. The spiral flow generation device according to claim 1, wherein the main cylinder and the annular gap forming portion of the auxiliary cylinder are detachable.