JPS62233489A - Bellows pump - Google Patents

Abstract

PURPOSE:To prevent damage of a bellows by installing a sleeve for smoothly connecting both end parts, at the cut both end parts of a ring-shaped core member of bellows made of fluorocarbon polymers. CONSTITUTION:Bellows 1 made of fluorocarbon polymers is constituted of a head part 8, a bellows part 9 and a flange part 10 and provided with a ring- shaped core member 11 to be installed in an inside periphery recess of the bellows part 9. A sleeve 12 for smoothly - approximately - connecting both end parts, is installed at these cut both end parts of the ring-shaped core member 11. Accordingly the sleeve rectifies the remained strain of the core member and cramps and the core member is installed, in that condition, in the bellows, so it doesn't cause deformation resulting from the remained strain of the core member and the damage of the bellows can be prevented.

Description

[Detailed description of the invention] [Industrial application field]

The present invention provides chemical solutions such as strong acids, strong alkalis, and organic solvents,
This article concerns a bellows pump suitable for metered pressure pumping of other fluids.

[Prior art]

In general, a constant m
A bellows pump is used as one of the pumps. It is mainly used for quantitatively pumping chemical solutions such as strong acids, strong alkalis, or organic solvents. For example, as an etching solution for semiconductors, it is used to quantitatively transport chemical solutions such as sulfuric acid, nitric acid, hydrogen peroxide, and hydrofluoric acid. It may be pumped. FIG. 10 is a schematic diagram showing the principle structure of this bellows pump, and the operation of the bellows pump will be explained according to this diagram. In the figure, numeral 3 indicates the operating part of the pump, and a pair of bellows 1.1' expand and contract alternately within the pump chamber 25.25° defined at both ends of the casing 15, thereby discharging the air. Pressure and suction pressure are created. Reference numerals 4, 5, and 6°7 are check valves, 47 is an inlet, and 33 is an outlet. When one bellow L is contracted and the other bellow L is extended, the check valve 4.6 opens, the check valves 5 and 7 close, and the liquid to be pumped is reversed from the suction port 47. It is sucked into one pump chamber 25° through the stop valve 6,
The liquid in the other pump chamber 25 is forced through the check valve 4 and sent from the discharge port 33 to the supply system. Note that the check valves 5.7, which are closed at this time, perform a rectifying function by preventing backflow on the discharge side and suction side, respectively. Each bellow 1. !
When ° operates in the opposite direction, each check valve 4, 5, 6
7 also performs the opposite operation, and similarly pumps the liquid from the discharge port 33 to the supply system. The expansion and contraction movements of the bellows t and t' are driven by a piston movement in the axial direction of a shaft member 2 whose both ends are fixed inside the tip of each bellows 1.1'. This piston movement of the shaft member 2 is caused by a casing-side partition 48 that airtightly and slidably holds the substantially central portion of the shaft member 2, and a shaft member 2 located on both sides of the casing-side partition 48.
A shaft-side partition wall 16 extends outward in the radial direction in a brim shape, and has a peripheral edge that slides airtightly into the inner circumferential surface of the casing I5.
It is driven by alternately applying air pressure to the two pressure chambers 22° and 22° formed between the two pressure chambers 22° and 22°. In the figure, 50 is a driving air pressure switching valve. FIG. 13 shows the above-mentioned bellows 1. FIG. 2 is a half-sectional front view showing a specific configuration of Io. The bellows 1.1' is made of fluororesin that is not attacked by chemical solutions such as the above-mentioned etching solution, and a ring-shaped core member 11 made of stainless steel is fitted into the recess on the inner circumferential surface of the bellows part to form the bellows. parts have been reinforced. Moreover, this ring-shaped core member 2 is cut at one point, and the one end of the cut point is sequentially fitted into the inner circumferential surface recess, and finally the other end of the cut point is inserted. It is configured as follows.

[Problems to be solved by the invention]

By the way, in the bellows pump configured as described above, when fitting the ring-shaped core member It into the inner peripheral surface recess of the bellows part 9 of the bellows L, the ring-shaped core member It is fitted in order while bending the core member 11. Therefore, as shown in FIG. 14, a residual strain is generated in the core member +1 according to the amount of deflection. This residual distortion is suppressed to some extent by the rigidity of the bellows 1 itself when the core member 11 is fitted into the bellows 1 at room temperature. In order to increase the reactivity of the fluororesin, it is pumped at a high temperature, and when the temperature reaches a high temperature of 100° C. or higher, the fluororesin gradually softens and its rigidity decreases. Therefore, it becomes impossible to suppress the residual strain in the core member It gradually, and when a certain limit is exceeded, the bellows portion 9 of the bellows 1 is also deformed, as shown in FIG. 13. As a result, cracks, pinholes, etc. occur in the bellows portion 9, causing problems such as leakage of the chemical liquid or mixing of grease (vaporized and turned into grease vapor) from the switching valve or the like into the chemical liquid. Note that semiconductor etching solutions are required to have extremely high purity (PPB units), and even a small amount of contamination cannot be ignored. The present invention has been devised in view of the above problems and to effectively solve them. Therefore, the purpose of this is to suppress the residual distortion of the ring-shaped core member from deforming the bellows part of the fluororesin bellows, prevent damage to the bellows, and prevent leakage of the chemical solution and mixing of grease, etc. into the chemical solution. Our goal is to provide a highly reliable bellows pump.

[Means to solve the problem]

The bellows pump according to the present invention is a bellows pump in which a ring-shaped core member with one end cut off is fitted as a reinforcing member in a recessed part on the inner circumferential surface of a fluororesin bellows. A sleeve is attached to connect these ends almost smoothly.

[Effect]

According to the bellows pump according to the present invention, the sleeve attached to the cut end of the ring-shaped core member corrects and restrains residual distortion of the core member, and in this state, the core member is fitted into the bellows. Therefore, even if the fluororesin bellows softens due to high temperatures, it will not be deformed due to residual strain in the core member.

【Example】

A preferred embodiment of the present invention will be described below with reference to FIGS. 1 to 9.
This will be explained with reference to the figures. FIG. 1 is a half-sectional front view of a bellows pump according to the present invention. An actuating part 3 including a bellows 1, a shaft member 2, etc. is located approximately in the center of the pump body, and check valves 4, 5, 6.7 are arranged at the four corners around it, and the basic structure is similar to that of the conventional technology. It is almost the same as that shown in FIG. 1O described in the section. Therefore, similar configurations will be given the same reference numerals to omit redundant explanations, and here mainly detailed configurations will be described in detail. It should be noted that the actuating portion 3 is constructed almost symmetrically in the same way as in the prior art, and the portions that are shown in the interrupted plane and the portions that are not shown have the same structure. First, bellows l will be explained. FIG. 2 is a half-sectional front view showing details of the bellows 1, and as shown in the figure, the head 8,
The bellows portion 9 and the flange portion 10 are integrally constructed. The material is a fluororesin that is not attacked by chemical solutions such as etching solutions. As shown in FIG. 3, a sleeve 12 is attached to the cut end of the ring-shaped core member 11 that is fitted into the recess on the inner peripheral surface of the bellows portion 9 of the bellows I. As shown in FIG. In this attached state, the thickness of the sleeve 12 and the thickness of the core member 11 are configured to be substantially uniform. That is, in order to absorb the wall thickness of the sleeve 12, the thickness at the cut end of the core member 11 is made thinner. Further, the sleeve 12 has a substantially "C"-shaped cross section, and the core member l! is passed through the open portion of the "C" shape from the radial direction! It is configured to be inserted. As shown in the figure, a guide portion 13 is formed at one end of the sleeve 12 and extends in a brim shape from both open ends of the rCJ shape to guide insertion of the core member 11. The procedure for attaching the ring-shaped core member 11 and the sleeve 12 to the bellows l is as shown in FIGS. In this state, the end of the core member 11 together with the sleeve 12 is fitted into the recess on the inner circumferential surface of the bellows portion 9. Subsequently, the remaining portions of the core member 11 are fitted into the four parts one after another, and finally the other end of the cut part is inserted into the sleeve 12 along the guide portion I3 of the sleeve 12. Due to this mounting process, a residual strain is generated in the core member 11 to form a helical shape, but the positional deviation at the cut end is corrected to a distortion-free state and restrained. Therefore, even if the bellows 1 made of fluororesin softens due to high temperature, it will not be affected by the residual strain of the core member 11, and there is no fear of damage due to this. In addition, the core member 11 is Hero 1
Each core member 1 is fitted into each inner peripheral surface recess (multiple strips) of
The positions of the individual sleeves 12 that are attached to the bellows 1 are arranged at approximately equal central angle positions on the inner circumferential surface of the bellows 1. Furthermore, bellows 1 is usually made of relatively permeable PT.
Because it is made of FE (polytetrafluoroethylene), it is designed to prevent metal corrosion of the stainless steel core member 11 and sleeve 12 from hydrofluoric acid, which has strong penetrating power. To prevent contamination, a tube made of PFA (perfluoroalkoxy resin), which is highly permeable, is placed over the core member 11 and the sleeve 12 in advance. Next, the shaft member 2 will be explained. Shaft member 2
, each bellows 1 has symmetrical ends (one is not shown).
The bellows 1 is connected to the center of the inner surface of the head 8 of the bellows 1 through a connecting pusher 14, and when the shaft member 2 moves as a piston within the casing 15, the bellows 1 alternately extend and contract. As a shaft-side partition wall that receives driving air pressure to participate in driving the shaft member 2,
A disk-shaped pressure receiving portion I6 is formed on this shaft member 2. In order to increase the discharge pressure by the bellows 1, the disk diameter is set so that the pressure receiving area is larger than the area of the head 8 of the bellows 1. The casing 15, which holds the disk-shaped pressure receiving part 16 and allows the piston movement of the shaft member 2 and the expansion and contraction movement of the bellows l, consists of a central drum part 17, a first cylinder part 18, a second cylinder part 18, Cylinder part 19
It consists of four main components: and a holding part 20. The center portion of the mass casing 15 holds the center portion of the shaft member 2 (the connection portion between the pair of left and right disk-shaped pressure receiving portions) in a slidable and airtight manner, and is provided with an inlet 21 for driving air pressure. A central drum section 17 is provided. 1st
Although not shown in the drawings, various mechanisms for switching the supply of driving air pressure to the left and right actuating parts are housed within the central drum portion 17. This central drum part 17
A first cylinder part 18 is provided adjacent to both sides of the central drum part 17, and the end face of the central drum part 17 serves as a casing side partition part, and this, the inner peripheral surface of the first cylinder part 18, and the disk-shaped pressure receiving part 1
6, a pressure chamber 22 is formed. That is, the disk-shaped pressure receiving portion 16 of the shaft member 2 is
Its circumferential side is the first cylinder part

The pressure chamber 22 is in sliding contact with the inner circumferential surface of the pressure chamber 22 while being sealed therebetween, and makes a piston movement to expand and contract the pressure chamber 22. As shown in FIG.
The end portion of the shaft member 2 is slidably held at the central portion of the shaft member 2 . Furthermore, a second cylinder part is adjacent to this first cylinder part 18! 9 is provided. This second cylinder part 1
A bellows l is housed within the bellows 9, and a pump chamber 25 is formed in which the medicinal solution is inhaled and discharged. Note that the second cylinder part 1
The inner circumferential surface of the bellows I is shaved off to a thickness of approximately 0.5 mm compared to the conventional one, and the bellows I will not come into contact with this inner circumferential surface even if it is deformed. Therefore, there is little risk of damage due to contact. Then, it is fitted to the peripheral edge of this second cylinder +1<19, and this is the first cylinder part! 8 is provided with a ring-shaped holding portion 20 for tightening and fixing. A bolt 26 is used as a fixing means for tightening. Each component of the casing 15 must be assembled to maintain airtightness, and strong tightening of bolts 26 and the like requires force. Therefore, each component itself must have the strength to withstand the force for strong tightening, and conventionally, components other than the parts that come into contact with the chemical solution, such as the bellows 1 and the second cylinder part I9, have been engineered. plastic was used. However, engineering plastics are not materials that have sufficient strength against temperature changes, and when used in environments with severe temperature changes, there is a risk of expansion failure such as cracks. In the pump of the present invention, these components that were previously made of engineering plastics are made of stainless steel to increase the strength against temperature changes and further increase the strength of the members, thereby increasing the tightening force. Each assembly was designed to improve airtightness. Note that stainless steel has better chemical resistance than engineering plastics, and is more reliable as equipment that handles chemical liquids such as etching liquid. Furthermore, in order to provide additional tightening allowance 27 between the holding part 20 and the first cylinder part 18, the length of the holding part 20 is made shorter than that of the conventional one, and the tightening force of the bolt 26 is increased. . By the way, the bellows 1 is fixed to the casing 15 by a flange portion l extending radially outward at the end of the bellows l.
This is done by sandwiching the cylinder O between the first cylinder part I8 and the second cylinder part 19 and tightening them. The width of the flange portion IO is made approximately equal to the wall thickness dimension of the second cylinder portion 19, and the entire end surface of the second cylinder portion 19 participates in maintaining its airtightness. This is an improvement over the conventional bellows 1 in which the width of the flange portion 10 was narrower than the wall thickness of the second cylinder portion 19, and its reliability is sufficiently increased. Further, a sliding annular convex portion 28 protruding from the disk-like portion 24 of the first cylinder portion 18 is in contact with the inner circumferential surface side of the flange portion IO along this. This is because the width of the conventional flange portion 10 was narrow, and the tightening of the first flange portion 10 and the second flange portion 10 by the holding portion 20 (=I is the force applied to the flange portion 10 outward in the radial direction). As the bellows lO acts from an oblique direction, the flange lO may gradually shift inward in the radial direction as the bellows l repeatedly expands and contracts, which may impair the airtightness of this part.The structure is designed to prevent this. In other words, the configuration in which the flange portion lO is widened is as follows.
This not only increases the sealing surface, but also contributes to increasing frictional force and preventing the above-mentioned inward tilting of the flange portion IO. Next, the structure of the plate-shaped portion 24 of the first cylinder portion 18 will be explained. FIG. 8 is a side view of the first cylinder portion 18 of this embodiment viewed from the plate-like portion 24 side, and FIG. 2 is a side view of the same in the prior art. As shown in FIG. 8, a boss portion 29 through which the shaft member 2 is inserted and supported is formed at the center. The holes formed at three locations around the boss portion 29 absorb most of the air pressure fluctuations within the bellows l as the bellows expand and contract. This is a communication hole 31 for escaping to a chamber 30 formed between the pressure receiving part 16 and the pressure receiving part 16 . These communication holes 31 allow the chemical solution to communicate even if a chemical solution such as an etching solution flows into the bellows 1 due to, for example, damage to the bellows 1 or breakage of the airtightness of the flange portion 10 of the bellows 1. 3 to prevent it from flowing into the chamber 30 side through the hole 31.
Both locations are located high above the center. Further, the communication hole 31 extends from the lowermost end of the plate-shaped portion 24 toward the center to slightly inside the inner circumferential surface of the bellows 1.
An air release groove 32 is formed to release air pressure fluctuations within the bellows 1 that cannot be released to atmospheric pressure. 28 in the diagram
is an annular convex portion that protrudes annularly along the inner peripheral surface side of the flange portion 10 of the bellows 1. Such a configuration of the plate-shaped portion 24 is a further improvement over the air release mechanism according to the prior art. That is, as for the conventional air release mechanism, (see FIG. 12, which is a cross-sectional view taken along line A-A in FIG. An air relief groove 32° is formed on the outer surface of the plate-like portion 24′ of the first cylinder portion 18′ (indicated with a dash like “Oo”), and an air release groove 32° is formed in the groove 32′ to vent the chamber. A communication portion T is formed that opens the 30° to the atmospheric pressure side. The air relief groove 32° on the outer surface side is configured to release air pressure fluctuations due to the expansion and contraction movement of the bellows l°, and the communication portion T is configured to release air pressure fluctuations due to the piston movement of the disc-shaped pressure receiving portion 16'. By the way, since this communication portion T is opened in the air relief groove 32', if, for example, there is a leakage of the chemical liquid into the bellows 1' as described above, the chemical liquid will pass through the air relief groove 32' and be released by gravity. Although it tries to flow out of the casing 15° in the direction, there is a risk that it will be sucked into the chamber 30° from the communication portion T by the negative pressure on the chamber 30° side accompanying the piston movement of the disc-shaped pressure receiving portion 16°. When the chemical solution is sucked into the chamber 30゜,
The sealing material provided on the circumferential side of the disc-shaped pressure receiving portion 16° is eroded, and the airtightness within the royal power chamber 22' cannot be maintained. In addition, since all of the pressure fluctuations within the bellows and within the chamber 30' are absorbed by the air relief groove 32' and the communication portion T, this iIX! The flow rate of air passing through 32' and the communication portion T has increased, and therefore the groove width has also had to be increased. Since the groove 32° portion does not come into contact with the flange portion 10' of the bellows l°, only this portion cannot suppress the flange portion lO° and the airtightness is low. Therefore, even if it is an essential configuration, it is preferable that the width be as narrow as possible. For example, in the case of the conventional technology, the width was about 91 Rm, but in this example, it is 3 ml! 1
The ability to maintain airtightness has been improved. Next, let's explain the structure of the check valve 4.5 on the discharge side. FIG. 9 is an enlarged sectional view of the main part showing the cross section of the check valve 4 provided at the discharge port 33, but the difference from the other check valve 5 is that the discharge port 33 is formed in the joint 34. The other configurations are the same. As shown in the figure, a ball 35 as a valve body, a valve seat 36, and a ball damper 37 are assembled together and fitted into the joint 34 from below. The joint 34 is made of fluororesin, which is not affected by chemicals such as etching liquid. Further, the joint 34 into which the ball 35 and the like are fitted is tightened to the second cylinder part 19 by a bolt 39 via a stainless steel holding plate 38. The valve seat 36 and the ball damper 37 are configured to be inserted through a fluid inlet formed on the lower surface of the joint 34, and the joint 3
4 is formed into an integral structure with a closed upper surface. In other words, in conventional joints, balls, valve seats,
The ball damper is configured to be fitted from the top of the joint, and for this purpose an opening that opens and closes is formed on the top of the joint. Further, the presser plate for tightening and fixing the joint to the second cylinder portion also serves as a lid for opening and closing the above-mentioned mouth, and it is necessary to seal between this lid and the joint. On the other hand, in this embodiment, since the upper surface of the joint 34 is closed and integrally molded, there is no need to seal that part, and the number of sealing parts is reduced, thereby increasing the ability to maintain airtightness. The valve seat 36 also includes a cylindrical portion 40 that fits into the fluid flow path from below the joint 34 to form a seat for the ball 35, and a cylindrical portion 40 that connects straight to the discharge port 33 from the side in the figure. The ball damper support part 41 extends upwardly in the figure from the cylindrical part 40 to form a channel and to support the ball damper 37 in contact with the inner upper surface of the joint 34. The cylindrical portion 40 has an inner diameter smaller than the conventional one, and is configured so that the ball 35 will not fall out of the cylindrical portion 40 even if the fluororesin is softened by high temperature. Incidentally, when the conventional inner diameter is 11.5 mm, it is set to 9.5 mm in this embodiment. The columnar bodies of the ball damper support portion 41 are connected in an annular manner at their upper portions to increase mutual rigidity, thereby stabilizing the posture of the ball damper 37 and reliably holding it. In the ball damper 37, the ball 35, which is a valve body, is connected to the valve seat 36.
When the ball 35 is pushed up by the discharge pressure against the urging force of the leaf spring part 42, the ball 35 is pushed up by the discharge pressure against the urging force of the leaf spring part 42.
Stopper part 43 that stops this ball 35 at the upper limit position
It is equipped with In particular, the leaf spring portion 42 of this embodiment is formed only of fluororesin, and the wall thickness at the tip is gradually reduced to provide elasticity. This is because the leaf spring part in the conventional technology has a structure in which an elastic metal core member is embedded in a rod-shaped fluororesin, and as the leaf spring part repeatedly undergoes elastic deformation, the metal This improvement was made to prevent the core member from being exposed on the surface of the leaf spring portion and causing metal contamination of the chemical solution. Conventionally, Engineering Plus Deck was used for the presser plate 38, but in this embodiment it is made of stainless steel, and its tightening force is increased to improve the sealing performance between the joint 34 and the second cylinder portion 19. is enhanced. In addition, the connection portion between each joint 34 and the pipe 44 that connects each discharge side check valve 4.5 and between each suction side check valve 6, 7 pushes out the pipe end of the vibrator 44, and Each joint 3
It is configured as a flare joint in which the tube end is tightened with a cap nut 46 via a packing 45 at the connection portion on the 4th side. According to the various structures explained above, for example, 1
．． First of all, it is possible to prevent damage to the bellows and increase its durability and reliability, and to prevent the expansion of other components due to high temperature and high pressure. Assembling due to distortion can prevent leaks (of chemical liquid or driving air pressure) from various parts, etc., and can improve the durability and reliability of the bellows pump itself. [Effects of the Invention] As is clear from the above explanation, according to the present invention, the following excellent effects are exhibited. That is, the sleeve attached to the cut end of the ring-shaped core member corrects and restrains the residual distortion of the core member, and in this state the core member is fitted into the bellows, so the fluororesin bellows Even if the core member softens due to high temperatures, it will not be deformed due to residual strain in the core member. Therefore, there is less risk of damage to the bellows, less risk of chemical liquid leakage and contamination of the chemical liquid with grease, etc., improving the reliability of the bellows pump and extending its life.

[Brief explanation of drawings]

FIG. 1 is a half-sectional front view of a bellows pump according to the present invention;
Fig. 2 is a half-sectional front view showing details of the bellows in this embodiment, Fig. 3 is a perspective view showing the ring-shaped core member and sleeve in this embodiment, and Figs. 4 to 7 each show this embodiment. FIG. 8 is a side view of the first ring part in this embodiment, and FIG. 9 is a perspective view showing the discharge side check valve in this embodiment. Fig. 1O is a schematic diagram showing the basic configuration of a bellows pump, Fig. 11 is a side view of the first cylinder part in the prior art, and Fig. 12 is a view taken along the line A-A in Fig. 1I. 13 is a half-sectional front view showing details of a bellows in the prior art, and FIG. 14 is a side view showing a ring-shaped core member in the prior art. l... Bellows, 2... Yaft member, 3... Actuating part, 4... Discharge side reverse valve, 5... Discharge side check valve, 6
...Suction side check valve, 7...Suction side check valve, 8...
Head of bellows, 9... Bellows part, lO... Flange part of bellows, 11... Ring-shaped core member, I2.
...Sleeve, 13...Guide part, 14...Connecting push, 15...Casing, 16...Disc-shaped pressure receiving part, 17...Central drum part, 18...
1st knolling part, 2nd knolling part, 20. Holding part, 21... Inlet for driving air pressure, 22... Pressure chamber, 23... Cylindrical part of first cylinder part, 24 ...First
Plate-shaped portion of the knolling member, 25... pump chamber, 26...
・Bolt, 27... Additional tightening allowance, 28... Annular convex portion, 29... Boss portion, 30... Chamber, 31... Communication hole, 32... Air relief groove, 33...・Discharge port, 34・
...Joint, 35...Ball, 36...Valve seat, 37
...Ball damper, 38...Press plate, 39...
Bolt, 40... Cylindrical part of valve seat, 41... Ball damper support part, 42... Temporary spring part, 43... Stopper part, 44... Pipe, 45... Packing, 46・・・
・Fukuronatsu Patent Applicant Patent Attorney for Kurashiki Boseki Co., Ltd. Aohaku Ao (and 2 others) Figure 12 Figure 13B Figure 14 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 90

Claims (3)

[Claims] (1), 1
In a bellows pump in which a cut-off ring-shaped core member (11) is fitted as a reinforcing member, a sleeve ( 12) A bellows pump characterized by being equipped with. (2) The outer diameter of the sleeve (12) is approximately equal to the cross-sectional diameter of the ring-shaped core member (11).
Bellows pump as described in section. (3) The sleeve (12) has a radial cross-sectional shape such that the cut end of the ring-shaped core member (11) is inserted into the sleeve (12) from the outside in the radial direction. It has a "C" shape and is open at one point, and the "C"
A guide portion (13) is bent outward from both open ends of the “” shape and extends in a brim shape, and guides the insertion of the core member (11).
) The bellows pump according to claim 1 or 2, wherein: