JP2016050573A - Cylinder, and cleaning method of cylinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylinder capable of properly cleaning a part on which cleaning may be insufficient, such as a part of an O-ring disposed between a piston head and a cylinder body, and a corner (angular portion) positioned at an outer side of a discharge port in the cylinder body.SOLUTION: A cylinder 1 includes a cylinder body 10 composed of a cylinder portion 12, and a cylinder cover portion 11 detachably mounted on a liquid discharge-side end portion of the cylinder portion 12 and having a liquid discharge port 11a, a baffle plate 14 disposed between the cylinder portion 12 and the cylinder cover portion 11, and a piston head 21 slidably disposed in the cylinder portion 12 at a liquid supply side with respect to the baffle plate 14, and provided with a liquid supply portion 31 having a liquid supply hole 31a on the center. The baffle plate 14 has a plurality of through flow channels 14a formed near an outer periphery of the baffle plate 14 for making a liquid pass to a cylinder cover portion 11 side from a cylinder portion 12 side.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a cylinder for supplying a liquid to an apparatus for applying a liquid, for example, a coating device (a coating apparatus) such as a spray gun.

A cylinder type pump (hereinafter referred to as a cylinder) in which a piston head is accommodated in a cylinder body is used to supply paint in a fixed amount to a coating device (painting device) such as a spray gun (see, for example, Patent Document 1). ).
And if it is left as it is after use, the paint will stick and the piston will not move in the cylinder body, and the next paint used may not be the same paint but another paint. For this reason, after use, cleaning liquid or the like is supplied into the cylinder body to clean the paint in the cylinder body.

  However, paint is likely to remain in places where the cleaning liquid does not flow easily, such as in the corners of the cylinder body, and the remaining paint is gelled or solidified. There is a problem that the paint is peeled off and the peeled paint is supplied to the coating equipment.

  For this reason, in Patent Document 1, the direction of the liquid supply port that supplies liquid (paint, cleaning liquid, etc.) into the cylinder body is formed so that the liquid fed into the cylinder body rotates in the cylinder body. The place where the flow of the washing liquid becomes bad is not made in the body.

Japanese Patent No. 4629515

However, a portion such as an O-ring provided between the piston head and the cylinder body has a small gap, so that the flow of the cleaning liquid is difficult to reach, and the paint still remains.
Also, in the vicinity of the discharge port for discharging the liquid in the cylinder body, the cleaning liquid does not flow to the corner (corner) inside the cylinder body outside the vicinity of the discharge port, but the cleaning liquid flows directly toward the discharge port. Therefore, the flow of the cleaning liquid is still poor and the liquid tends to remain.

  The present invention has been made in view of the above circumstances, such as an O-ring portion provided between a piston head and a cylinder body, a corner (corner portion) located outside a discharge port in the cylinder body, and the like. It is an object of the present invention to provide a cylinder capable of suitably cleaning a place where the cleaning is likely to be insufficient.

The present invention is grasped by the following composition in order to achieve the above-mentioned object.
(1) A cylinder according to the present invention includes a cylinder main body including a cylinder tube portion and a cylinder lid portion having a liquid discharge port formed at a center of the cylinder tube portion in a removable manner at a liquid discharge side end portion of the cylinder tube portion; A baffle plate provided between a cylinder cover and the cylinder lid portion, and a liquid supply portion which is slidably disposed in the cylinder cylinder portion on the liquid supply side with respect to the baffle plate and has a liquid supply hole is provided in the center. A piston head, and the baffle plate has a plurality of through channels that allow liquid to pass from the cylinder tube portion side to the cylinder lid portion side formed near the outer periphery of the baffle plate.

(2) In the configuration of (1) above, a total opening cross-sectional area obtained by summing up the opening cross-sectional areas of the through passages is smaller than the cross-sectional area of the liquid supply hole of the liquid supply unit.

(3) In the configuration of (1) or (2), the baffle plate includes a groove formed on the surface facing the piston head from the center toward the outside.

(4) In any one of the constitutions (1) to (3), the liquid supply part and the piston head are separate parts, and are detachably attached to the side of the piston head that does not face the baffle plate. A cylindrical piston rod; and a liquid supply pipe disposed in the piston rod and connected to the liquid supply unit, wherein the liquid supply unit is formed in the center of the piston head. By being detachably mounted in the hole, the liquid supply pipe is detachably connected to the piston head, and the liquid supply pipe has an inner diameter substantially equal to the liquid supply hole of the liquid supply unit. As a result, there is almost no step which becomes a pool of liquid supplied from the liquid supply pipe to the liquid supply hole.

(5) The cleaning method of the present invention is a cleaning method for cleaning any one of the cylinders of (1) to (4) above, wherein the cleaning liquid is supplied from the liquid supply unit to the liquid discharge port through the through channel. A step of reciprocating the piston head in the cylinder tube portion while flowing, and the reciprocating movement is performed in a range where the separation distance between the piston head and the baffle plate is within 10 mm.

  According to the present invention, it is preferable that a portion such as an O-ring provided between the piston head and the cylinder main body or a corner (corner portion) located outside the discharge port in the cylinder main body is likely to be insufficiently cleaned. A cylinder capable of being cleaned can be provided.

It is a perspective view of the cylinder which concerns on embodiment of this invention. FIG. 2 is an exploded plan view of the cylinder of FIG. 1. It is sectional drawing of the cylinder of FIG. It is a disassembled perspective view of the cylinder cover part vicinity of the cylinder of FIG. It is sectional drawing of the cylinder cover part vicinity of the cylinder of FIG. 1, and is a figure explaining the flow of a washing | cleaning liquid. It is an enlarged view of A part of FIG.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as embodiments) will be described in detail with reference to the accompanying drawings. Note that the same number is assigned to the same element throughout the description of the embodiment.
Further, in each member, “one end (side)” indicates a side close to the liquid discharge port side when assembled in a cylinder state, and “the other end (side)” conversely from the liquid discharge port. Indicates the far side.

FIG. 1 is a perspective view showing an external appearance of a cylinder 1 of the present invention.
As shown in FIG. 1, the cylinder body 10 includes a cylinder tube portion 12 and a cylinder lid portion 11 that is detachably attached to the liquid discharge side end portion of the cylinder tube portion 12 by an attachment component 13.
The cylinder lid 11 is formed with a through-hole serving as a liquid discharge port 11 a at the center, and the liquid supplied from the liquid supply pipe 30 disposed in the piston rod 20 is the liquid at the center of the cylinder lid 11. The liquid is discharged from the discharge port 11a, and the liquid is supplied to a coating device (liquid coating apparatus) (not shown).

A valve (not shown) is provided on the base end side (right side of the drawing) of the liquid supply pipe 30, and a liquid supply pump (not shown) is provided on the base end side of the valve. By driving this pump in the released state, the liquid in the liquid tank (not shown) is supplied into the cylinder body 10.
Note that a liquid discharge pipe (not shown) connected to the liquid discharge port 11a of the cylinder lid portion 11 is a pipe branched into the coating equipment side and the liquid tank side, and is driven into the cylinder body 10 by driving a pump. When supplying the liquid, the valve provided in the piping to the coating equipment side is closed, and the valve provided in the piping to the liquid tank side is opened.

  Then, the liquid supplied to the cylinder body 10 by the pump from the liquid tank is circulated back through the liquid discharge pipe connected to the liquid discharge port 11a of the cylinder lid portion 11 into the liquid tank, so that air or the like remains. The cylinder body 10 is filled with liquid so as not to be present.

  When the cylinder body 10 is filled with the liquid, the liquid supply pipe 30 and the liquid discharge pipe connected to the liquid discharge port 11a of the cylinder lid portion 11 are provided on the liquid tank side pipe. By driving the piston rod 20 after the valve is closed and the valve provided in the pipe to the coating device side of the liquid discharge pipe connected to the liquid discharge port 11a of the cylinder lid portion 11 is opened. A predetermined amount of liquid filled in the cylinder body 10 is pushed out by a piston head (not shown) provided at the tip of the piston rod 20 and supplied to a coating device, so that A fixed amount of liquid is applied.

Next, referring to FIG. 2 which is an exploded plan view of the cylinder 1 of FIG. 1 and FIG. 3 which is a sectional view of the cylinder 1 of FIG. To do.
As shown in FIGS. 2 and 3, a step portion (see FIG. 3) is provided on the inner peripheral surface of the liquid discharge side end portion of the cylinder tube portion 12, and the baffle plate 14 is fitted to the step portion. Place. A detailed description of the baffle plate 14 will be given later.

Further, a ring groove (see FIG. 3) is formed on the end surface of the liquid discharge side end portion of the cylinder tube portion 12, and an O-ring 15 is disposed so as to be fitted into the ring groove.
In this state, the cylinder lid portion 11 is placed on the liquid discharge side end portion of the cylinder cylinder portion 12 so as to hold the baffle plate 14, and the cylinder lid portion 11 is detachably attached to the cylinder cylinder portion 12 with the attachment component 13.
In this way, the baffle plate 14 is provided between the end of the cylinder tube portion 12 and the cylinder lid portion 11.

Next, the assembly of parts such as the piston head 21 slidably disposed in the cylinder tube portion 12 will be described.
A groove portion 21a is formed on the outer peripheral surface on one end side of the piston head 21, and an auxiliary sliding guide ring 22 is fitted into the groove portion 21a from one end side, and further, an O-ring 23 is fitted from one end side.
The auxiliary sliding guide ring 22 is made of a material that is harder than the O-ring 23 and hardly deforms, and is a member that plays a role of alignment when the piston head 21 slides in the cylinder tube portion 12.

On the other hand, the O-ring 23 is a member made of an elastic material that is elastically deformed between the piston head 21 and the cylinder tube portion 12 so that a gap is not formed.
Subsequently, the sliding guide ring 24 is attached to the outer periphery 21b on the other end side of the piston head 21 from the other end side.
This sliding guide ring 24 is also made of the same material as the auxiliary sliding guide ring 22 and is a member that plays a role of alignment when the piston head 21 slides in the cylinder tube portion 12 in cooperation with the auxiliary sliding guide ring 22. It is.

A step surface 20a is formed on the outer periphery of an end portion (one end side end portion) on the piston head 21 side of the piston rod 20, and after the fastening ring 25 is fitted to the step surface 20a, the sliding guide ring 24 is fitted. By fixing the piston rod 20 to the other end side of the piston head 21 to which the slider is attached, the sliding guide ring 24 is fastened to the piston head 21 by the fastening ring 25, and the sliding guide ring 24 is fastened and fixed to the piston head 21. .
A ring member 26 is attached to the outer peripheral surface of the other end of the piston rod 20.

More specifically, the fixing of the piston rod 20 will be described. The inside of the other end side of the piston head 21 has a hollow shape in which a female screw structure is formed, and on the other hand, on the surface of the step surface 20a of the piston rod 20. Has a male screw structure.
Therefore, the piston rod 20 can be fixed to the piston head 21 by screwing the male screw structure of the piston rod 20 into the female screw structure of the piston head 21.

Further, as shown in FIG. 3, a liquid supply portion through hole 21c having a diameter smaller than that of the hollow portion communicating with the hollow portion described above from one end side is formed on one end side of the piston head 21. A female screw structure corresponding to the male screw structure formed on the outer periphery of the liquid supply part 31 is also formed in the through hole 21c for the liquid supply part.
The diameter of the liquid supply part through hole 21 c is substantially equal to the outer diameter of the liquid supply part 31.

As shown in FIG. 3, the piston rod 20 is also formed in a hollow shape from the other end side toward the one end side, so that the piston rod 20 has the liquid supply pipe 30 disposed inside the piston rod 20. A liquid supply unit 31 is attached to the end of the liquid supply pipe 30 that is inserted from the other end side of the piston rod 20 into the one end side of the piston rod 20 through the inside of the piston rod 20.
Therefore, prior to the mounting of the piston rod 20 to the piston head 21 described above, the liquid supply part 31 is detachably attached to the piston head 21 so that the liquid supply part 31 is positioned in the liquid supply part through hole 21c of the piston head 21. By screwing the liquid supply part 31, the liquid supply pipe 30 is detachably connected to the piston head 21.

  Prior to the connection of the liquid supply pipe 30 to the piston head 21 described above, the retaining member 16 that prevents the piston head 21 attached to the end of the cylinder tube portion 12 opposite to the end of the liquid discharge side from coming off is provided. The piston head 20 is inserted into the piston rod 20, and after the connection of the liquid supply pipe 30 to the piston head 21 and the fixing of the piston rod 20 are finished, the piston head 21 is inserted into the cylinder tube portion 12, By fixing the retaining member 16, the cylinder 1 shown in FIG. 1 is obtained.

Next, the function and effect of the cylinder 1 having the above configuration will be described.
FIG. 4 is an exploded perspective view in the vicinity of the cylinder lid portion 11 of the cylinder body 10.
Note that FIG. 4 is a view in which a part of the attachment part 13 is cut away so that the inside can be seen.
As can be seen from FIG. 4, on the outer periphery of the baffle plate 14, a plurality of through passages 14 a are formed along the outer periphery to allow liquid to pass from the cylinder tube portion 12 side to the cylinder lid portion 11 side.
As shown in FIG. 3, the through channel 14 a is formed so as to open to the outer periphery of the cylinder lid portion 11.
On the other hand, on the central side of the baffle plate 14, there is no through hole and it is in a closed state.

FIG. 5 shows the flow of the cleaning liquid when the cleaning liquid is supplied in a state where such a baffle plate 14 is provided.
As shown in FIG. 5, the cleaning liquid supplied into the cylinder cylindrical portion 12 from the liquid supply hole 31 a of the liquid supply portion 31 provided in the center of the piston head 21 collides with the baffle plate 14. , Flows outward along the baffle plate 14.

Here, in the portion of the baffle plate 14 where there is no through passage 14a, the cleaning liquid flows along the cylinder cylinder portion 12 so as to return to the piston head 21 side without going to the cylinder lid portion 11 side. It flows into the gap between the cylindrical portion 12.
For this reason, the cleaning liquid reaches the O-ring 23 located in the gap, and the liquid adhering to the gap or the O-ring 23 is washed.
On the other hand, since the cleaning liquid that flows to the cylinder lid 11 side through the through-flow passage 14a of the baffle plate 14 is ejected to the outer portion of the cylinder lid 11, the liquid adhering to this end portion is washed well. To the liquid discharge port 11a.
Therefore, it is possible to satisfactorily clean the outer corners (corner portions) of the O-ring and the liquid discharge port 11a, which conventionally have been insufficiently cleaned.

By the way, when the discharge port is smaller than the liquid supply port, the flow rate of the liquid discharged from the discharge port is increased, that is, the momentum of the liquid is increased.
Therefore, the through flow passage 14a is formed so that the total opening cross sectional area obtained by summing the opening cross sectional areas of the through flow passages 14a provided in the baffle plate 14 is smaller than the cross sectional area of the liquid supply hole 31a of the liquid supply portion 31. It is possible to increase the momentum of the cleaning liquid blown to the cylinder lid portion 11 side, and it is possible to increase the cleaning power.
Therefore, it is preferable that the total opening cross-sectional area obtained by summing the opening cross-sectional areas of the through flow passages 14 a provided in the baffle plate 14 is smaller than the cross-sectional area of the liquid supply hole 31 a of the liquid supply unit 31.

Further, as shown in FIG. 6, which is an enlarged view of a portion A indicated by a dotted-line square in FIG. 5, the inner diameter of the liquid supply pipe 30 is set to be approximately equal to the liquid supply hole 31 a of the liquid supply unit 31. .
For this reason, the liquid supply pipe 30 and the liquid supply part 31 are connected in a state where there is almost no step that becomes a reservoir of the liquid supplied from the liquid supply pipe 30 to the liquid supply hole 31a.
Accordingly, since there is no step where the liquid accumulates, there is no portion difficult to clean with the cleaning liquid.

Furthermore, the cylinder 1 can be easily disassembled and cleaned because the cylinder lid 11 is detachable from the cylinder cylinder 12.
In addition, since the liquid supply unit 31 is detachably attached to the piston head 21, the liquid supply pipe 30 can be easily removed by removing the liquid supply unit 31.
Therefore, when the liquid adheres to the inner surface of the liquid supply pipe 30, it can be easily replaced with a clean liquid supply pipe 30.
However, from the viewpoint of reducing the number of parts, the liquid supply unit 31 may be formed integrally with the piston head 21.
The material of the liquid supply pipe 30 is preferably a pipe made of a fluorine-based resin that hardly causes liquid sticking.

On the other hand, in the cylinder 1, the hollow piston rod 20 is screwed onto the piston head 21 and attached.
In general, the piston head 21 and the piston rod 20 are often formed integrally. In this case, since the dimensional accuracy required for the piston head 21 is high, the piston head 21 and the piston rod 20 are formed by machining. A part will be formed.

  However, in the cylinder 1 of the present invention, since the piston head 21 and the piston rod 20 are configured as separate parts, only the portion of the piston head 21 that requires dimensional accuracy is manufactured by cutting, and the portion of the piston rod 20 is Since it can be produced by selecting a desired strength from commercially available seamless pipes and performing simple processing, the production cost can be greatly reduced.

Furthermore, it is possible to significantly reduce the mass of the piston rod 20 by using a pipe material having a minimum necessary thickness that can provide the required strength.
For example, reducing the mass by the above-described cutting increases the amount of cutting and leads to an increase in cost. However, the thickness of the seamless pipe tends to be low because the material cost is reduced. It is in.
Thus, by using a pipe material for the piston rod 20, it is possible to simultaneously realize both a reduction in mass and a reduction in parts price.

Next, a suitable cleaning method for the cylinder 1 having the above-described configuration will be described.
First, the piston rod 20 is driven so that the piston head 21 is brought close to the baffle plate 14, and the liquid in the cylinder tube portion 12 is discharged as much as possible.
For example, the piston head 21 is moved closer to the baffle plate 14 until the distance between the baffle plate 14 and the piston head 21 is within 10 mm, more preferably within 5 mm.

  This distance is the distance between the surface of the baffle plate 14 that faces the piston head 21 and the surface of the piston head 21 that faces the baffle plate 14, and thereafter, the distance between the baffle plate 14 and the piston head 21. The distance between them is defined as the distance between the surface of the baffle plate 14 facing the piston head 21 and the surface of the piston head 21 facing the baffle plate 14.

  In this state, the cleaning liquid is supplied from the liquid supply pipe 30 for a predetermined time, and the liquid remaining in the cylinder body 10 is discharged by discharging the cleaning liquid from the liquid discharge port 11a of the cylinder lid portion 11. .

  Next, when a predetermined time elapses, the piston rod 20 is driven while the cleaning liquid is supplied from the liquid supply pipe 30 and the cleaning liquid is discharged from the liquid discharge port 11a of the cylinder lid 11. Then, the piston head 21 is moved to the side away from the baffle plate 14, and the operation of washing away the liquid adhering to the inner side surface of the cylinder tube portion 12 with the cleaning liquid is performed.

  When the piston head 21 reaches the position farthest from the baffle plate 14 of the cylinder tube portion 12, the supply of the cleaning liquid is stopped, and the piston head 21 is moved again to the baffle plate 14 side. In addition, the piston head 21 is brought close to the baffle plate 14 until the distance between the piston head 21 and the baffle plate 14 is within 10 mm, more preferably within 5 mm, and the cleaning liquid in the cylinder body 10 is discharged.

  After the cleaning liquid is discharged as described above, the supply of the cleaning liquid is started again, and this time, the distance between the piston head 21 and the baffle plate 14 is within 10 mm with respect to the baffle plate 14. The piston rod 20 is driven so as to reciprocate the piston head 21 so as to periodically repeat the approach and separation of the piston 21, and the piston head 21 is reciprocated a predetermined number of times.

  When the cleaning liquid is supplied in a state where the distance between the piston head 21 and the baffle plate 14 is within 10 mm, the supplied cleaning liquid is efficiently rebounded by the baffle plate 14, so that the good flow of the cleaning liquid described in the above-described effect is realized. In addition, the cleaning liquid in the cylinder body 10 is shuffled violently by reciprocating the piston head 21 within a range of a separation distance of 10 mm or less, so that the O-ring 23 and the cylinder lid 11 can be efficiently moved. Liquid attached to corners (corners) can be washed away.

  Therefore, as in the prior art, full-stroke cleaning, that is, cleaning is repeated while reciprocating the piston head 21 between the liquid discharge port 11a side and the side farthest from the liquid discharge port 11a. Compared to the above, not only can the cleaning time be greatly reduced and the amount of cleaning liquid used can be greatly reduced, but in particular, the portion where the liquid tends to remain (the corners of the O-ring 23 and the cylinder lid portion 11). Part)) can be intensively and efficiently cleaned, so that it is possible to greatly reduce the residual amount of liquid adhering to the O-ring 23, the corner (corner part) of the cylinder lid part 11, and the like.

As mentioned above, although this invention was demonstrated using embodiment, it cannot be overemphasized that the technical scope of this invention is not limited to the range as described in the said embodiment.
In the above embodiment, the piston rod 20 is a cylindrical member, and the piston rod 20 is detachably attached to the piston head 21, thereby reducing the mass and reducing the cost of components.

  In addition, the liquid supply pipe 31 is connected to the piston head 21 at the end of the liquid supply pipe 30, and a liquid supply part 31 is provided to supply the liquid. The liquid supply part 31 is detachably attached to the piston head 21. Therefore, the liquid supply pipe 30 is also detachably connected to the piston head 21 so that the liquid supply pipe 30 up to the piston head 21 can be easily replaced.

  Needless to say, it is preferable to adopt such an aspect, but the cleaning performance of the portion of the cylinder body 10 where the liquid tends to remain (such as the O-ring 23 and the corner (corner portion) of the cylinder lid portion 11) is improved. From this point of view, it is not an essential requirement.

  Therefore, the piston head and the piston rod are integrally formed, and a through hole serving as a liquid passage is formed from the position opposite to the piston head of the piston rod to the piston head, and the piston rod of the through hole is formed. You may change into the form where the liquid supply piping which supplies the liquid from a liquid tank is connected to the opening part of the side.

Moreover, in the said embodiment, although the surface facing the piston head 21 of the baffle board 14 is made into the flat surface, you may make it form a groove | channel from this center toward an outer side.
For example, when a groove is formed toward the outer periphery of the baffle plate 14 where the through flow path 14a is not provided, the cleaning liquid supplied from the liquid supply hole 31a flows along the groove, and thus directly toward the through flow path 14a. The amount of the cleaning liquid can be reduced, and instead, the amount of the cleaning liquid directed toward the piston head 21 along the cylinder tube portion 12 can be increased, so that the vicinity of the O-ring 23 can be more preferably cleaned. Become.
Even in this case, the cleaning liquid that has been cleaned in the vicinity of the O-ring 23 vigorously flows to the cylinder lid portion 11 side through the through flow passage 14a, so that the cylinder lid portion 11 side can also be suitably cleaned.

  As described above, it will be apparent to those skilled in the art that various modifications or improvements can be made to the above-described embodiment, and embodiments to which such modifications or improvements are added are also included in the technical scope of the present invention. This is apparent from the description of the scope of claims.

DESCRIPTION OF SYMBOLS 1 Cylinder 10 Cylinder main body 11 Cylinder cover part 11a Liquid discharge port 12 Cylinder cylinder part 13 Mounting part 14 Baffle plate 14a Through flow path 15 O-ring 16 Prevention member 20 Piston rod 20a Step surface 21 Piston head 21a Groove part 21b On the other end side Outer periphery 22 Auxiliary sliding guide ring 23 O-ring 24 Sliding guide ring 25 Tightening ring 26 Ring member 30 Liquid supply pipe 31 Liquid supply part 31a Liquid supply hole

Claims (5)

A cylinder body comprising a cylinder tube portion and a cylinder lid portion having a liquid discharge port formed in the center thereof, which is detachably provided at a liquid discharge side end portion of the cylinder tube portion;
A baffle plate provided between the cylinder tube portion and the cylinder lid portion;
A piston head that is slidably disposed in the cylinder tube portion on the liquid supply side of the baffle plate and has a liquid supply portion having a liquid supply hole in the center;
The cylinder according to claim 1, wherein the baffle plate has a plurality of through passages that allow liquid to pass from the cylinder tube portion side to the cylinder lid portion side formed near the outer periphery of the baffle plate.   2. The cylinder according to claim 1, wherein a total opening cross-sectional area obtained by summing up the opening cross-sectional areas of the through passages is smaller than a cross-sectional area of the liquid supply hole of the liquid supply unit.   The cylinder according to claim 1 or 2, wherein the baffle plate includes a groove formed on a surface facing the piston head from the center toward the outside. The liquid supply unit and the piston head are separate parts,
A cylindrical piston rod detachably attached to a side of the piston head that does not face the baffle plate;
A liquid supply pipe disposed in the piston rod and connected to the liquid supply unit,
The liquid supply pipe is detachably connected to the piston head by being detachably attached in a through hole for a liquid supply part formed in the center of the piston head,
The liquid supply pipe has almost the same inner diameter as the liquid supply hole of the liquid supply section, so that there is almost no step that becomes a pool of liquid supplied from the liquid supply pipe to the liquid supply hole. The cylinder according to any one of claims 1 to 3. A cylinder cleaning method according to any one of claims 1 to 4, wherein
Including reciprocating the piston head in the cylinder cylinder part while flowing a cleaning liquid from the liquid supply part to the liquid discharge port through the through channel,
The reciprocation is performed in a cleaning method in which a separation distance between the piston head and the baffle plate is within 10 mm.

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