JP2589995B2 - Submersible displacement piston pump - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates generally to submersible positive displacement piston pumps and, more particularly, to submersible piston pumps with particular applicability to dispensing small volumes of liquid to utilization devices. Related to a positive displacement piston pump.

It is well known to use pumps to meter small amounts of liquid from a transport drum to a utilization device. For example, U.S. patent application Ser. No. 06 / 566,363 (filed on Dec. 28, 1983), which has the same successor as the present invention, discharges a liquid pulse at a fixed rate and sends one pulse from the transport drum to the point of use. A pneumatically driven diaphragm pump is described that delivers 2-3 liters of chemical per day. The application point may be, for example, a coating hood for coating a glass bottle.

The advantage of this pump is that it uses a pneumatically operated valve that prevents liquid leakage normally found in pumps that use a conventional ball check valve. However, even though this pump produces good results, differences in processing tolerances and membrane quality, for example, a 20% stroke volume difference exists between separate pneumatically driven diaphragm pumps. There can be.

To overcome these shortcomings, U.S. Patent Nos. 3,168,872, 3,257,953, 4,00
A positive displacement piston pump is used which has been modified according to US Pat. No. 8,003 and, in particular, US Pat. No. 4,536,140. The entire disclosure of U.S. Patent No. 4,536,140 is hereby incorporated by reference herein. This latter U.S. patent pump has been found to be suitable for pumping liquid organometallic compounds used in coating glass vials with tin oxide or other metal oxides.

In these pumps, the pumping chamber is located outside the transport drum and the hose from the fluid inlet extends into the transport drum. To this end, the chemicals are pumped from the drum via a hose into the pumping chamber. However, U.S. Pat.
As noted in US Pat. No. 6,140, one problem with positive displacement piston pumps is that even with the tightest manufacturing tolerances between the reciprocating piston and the cylinder inner wall, the space between the piston and the cylinder inner wall is difficult. Chemicals are regularly transferred from the pumping chamber. If the chemical is a corrosive substance, such as a formulation containing monobutyltin trichloride, the transfer of the metal liquid compound between the reciprocating piston and the inner wall of the cylinder, even with the transfer of a small amount of liquid chemical Becomes This compound is formed by the reaction of chemicals with water vapor in the surrounding air.
The piston is stuck in the cylinder by this production, causing the device to fail.

In U.S. Pat. No. 4,536,140, an attempt is made to overcome these disadvantages by placing another oil barrier of constant hydraulic pressure between the piston and the cylinder inner wall. However, the use of such barriers significantly complicates the device. Also, in some applications, the seal oil interferes with the operation of the pump.

Another problem with these pumps is that the small amount of air entering the pump prevents proper operation and reduces pumping speed. More specifically, gases contained in the fluid, such as air, hydrogen, carbon dioxide, and the like, are often released into the cylinder as a result of agitation of the fluid during pumping or changes in pressure and temperature. As an example, some fluids may be chemically separated into a liquid fraction and a gas fraction to respond to agitation and / or changes in temperature and pressure, while other fluids may simply evaporate from the liquid form. Physically changes to gaseous form. As a result, bubbles form from the gas, which trap in the pumping head of the cylinder, thereby reducing the metering accuracy of the pump and, in some cases, completely shutting off the flow. Bubbles are generally trapped between the recess of the piston and the inner wall of the cylinder.

More specifically, if the pump is not running at full capacity, i.e., if the piston has pivoted to less than its maximum value, the piston will travel over a smaller distance between the retracted and extended positions. Reciprocate. Therefore,
The upper end of the recess always remains above the discharge port during the reciprocating movement of the piston. Therefore, air bubbles formed between the recess and the inner wall of the cylinder remain during the operation of the pump and hinder the operation of the pump. As can be seen, the smaller the piston stroke, the more gas is trapped in the recess, thereby increasing the ratio of the volume of trapped gas to the discharge of the pump. In other words, the pump becomes sensitive to gas.

Due to this problem, pumps operating at less than full capacity must change their flow rate several times. In this case, the trapped gas flows out of the pump and recovers the set discharge amount. However, changing this ability is time consuming and tedious. For example, if a pump is used to pump fluid for bottle coating, the change in capacity may result in excessive use of expensive coating material or insufficient bottle coating.

The problem with such a small amount of air flowing into the pump is described in U.S. Patent Application No. 749,066 (filed June 6, 1985).
And the entire disclosure of this U.S. patent application is incorporated herein by reference.

OBJECTS AND SUMMARY OF THE INVENTION It is therefore one object of the present invention to provide a positive displacement piston pump that prevents piston sticking in a cylinder.

It is another object of the present invention to provide a positive displacement piston pump which prevents a metal hydroxy compound from adhering between a reciprocating piston and an inner wall of a cylinder.

It is yet another object of the present invention to provide a positive displacement piston pump that eliminates the need for using a barrier fluid.

It is yet another object of the present invention to provide a positive displacement piston pump which prevents the formation of unwanted air bubbles in the cylinder chamber.

The submersible positive displacement piston pump of the present invention is a cylinder means capable of being completely immersed in a liquid, the cylinder means having a working chamber defined by a working lower end, an inlet port, and a discharge port. Piston means capable of simultaneously rotating and reciprocating between a retracted position and an extended position within said cylinder means for pumping liquid from said inlet port to said discharge port, said piston means comprising: Said piston means having a free end disposed therein, said free end having a recess for alternately communicating liquid to said inlet port and said discharge port; and drive means for driving said piston means. A rotating assembly rotatably connected to the driving means for rotatably and reciprocally driving the piston means in the cylinder means; and the rotating assembly. Is connected to the piston means, and is extended means for arranging the driving means and the rotating assembly outside the liquid, wherein the extending shaft connects the rotating assembly and the piston means, and surrounds the extended shaft. The extension means having a hollow extension pipe, and the lower end of the hollow extension pipe is fixedly sealed to the upper end of the cylinder means, and the liquid level of the liquid is lower than the upper end of the cylinder means. In addition, in order to maintain a liquid-tight state at the upper end of the cylinder means, the hollow extension tube has an opening slightly above the sealing fixing portion.

Also provided is a means for guiding the drive means during the rotational movement of the drive means to ensure that the recess is completely located in the working chamber when the piston means is in the extended position. It is characterized by the following.

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial longitudinal sectional view showing a submersible positive displacement piston pump according to an embodiment of the present invention, FIG. 2 is a part of the pump of FIG. FIG. 3 is a partial sectional view of the piston-cylinder end of the pump of FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings and first to FIG. 1, a liquid organometallic compound used to coat a vial with tin oxide or other metal oxides A submersible positive displacement pump according to one embodiment of the present invention is shown, for example, suitable for pumping pumps.

As shown in FIGS. 1 and 3, the pump 10 has a hollow cylinder 12, which has a closed working lower end 14 and an inner bore.
And an opposite end 15 with 16. The inlet and outlet ports 18, 20 facing diametrically above are
Adjacent to 4, each is formed in a cylinder 12.
The discharge pipe connecting portion 22 is fixed to the outside of the cylinder 12 in a relationship surrounding the discharge port 20, and the discharge hose
A coupling 23 for fixing one end of the coupling 24 is provided. Accordingly, the fluid to be pumped is discharged from the discharge port 20 toward the discharge hose 24. The working chamber 26 is similarly formed in the cylinder 12 and is defined by the working lower end 14 and the ports 18, 20 and is in communication with the ports 18, 20.

A piston 28 is rotatably and reciprocally movable in the cylinder 12 through the bore 16, and has a free end 30 and a driven end 32.
And The free end 30 has a flat recess 34 which is in sequential fluid communication with the ports 18, 20 as the piston 28 rotates in the cylinder 12. Thus, the recess 34 acts as a duct between the ports 18 and 20, opening and closing the ports 18 and 20 alternately in turn. The recess 34 cooperates with the portion of the working chamber 26 at the top of the piston 28 to form a cylinder pumping chamber, which pumps fluid between the ports 18,20.

On the other side of the pump 10 is a drive motor 36 with an output drive shaft 38, which is mounted on a substrate 40. An electrical cable 42 extends through a cable protection hose 44, which is connected to the housing of the motor 36 to power the motor. Little boss
The collar or yoke 46 with 48 is provided on the drive shaft by any suitable means, such as a pin extending through the boss 48 and drive shaft 38.
It is keyed to 38. The yoke 46 has a socket 52. A laterally projecting ground or lateral arm 54 is secured to one end of a shaft 56, and a ball bearing 58 is secured to the other end of the arm 54. Ball 58 is received in socket 52 to form a universal ball and socket joint. Thus, as the drive shaft 38 rotates, the shaft 56 rotates and reciprocates in a known manner, as described in the aforementioned U.S. patent for positive displacement piston pumps.

As can be seen, this ball and socket joint device
Of the drive shaft 38 with respect to. As is well known, the amount of reciprocation (and therefore the position of piston 28 in cylinder 12) varies depending on the angle at which drive shaft 38 rotates relative to shaft 56. Therefore, the pump stroke changes with this angle. For example, when the drive shaft 38 rotates to the maximum extent with respect to the shaft 56, i.e., when the pump is operating at the maximum pump stroke, the piston reciprocates a maximum distance between the retracted position and the extended position in the cylinder 12. exercise.

According to the invention, the piston 28 is
, The motor 36 controls both rotation and reciprocation of the piston 28 in the cylinder 12. The piston connector 61 is connected to the lower end of the extension shaft 60 to connect the piston 28 to the extension shaft 60. With this arrangement, the cylinder 12 and piston 28 are submerged at the bottom of the liquid 62 in the drum 64, and the motor 36 and associated members of the drive end of the assembly are held outside of the drum 64 and the liquid 62. .

This offers distinct advantages not achieved by the prior art. In particular, since the compound in the cylinder has not been exposed to the surrounding air, the problem of metal hydroxy compounds forming in the space between the piston and the cylinder wall is overcome. Therefore, the piston is not fixed in the cylinder. Also, since these disadvantages in the prior art are overcome, U.S. Pat.
No oil barrier as described in the item is required.

As shown in FIG. 1, the extension shaft 60 is surrounded by a hollow extension tube 66, and the hollow extension tube 66 is
The lower end is fixed in a sealed manner, and extends outside the drum 64, and the upper end is fixed to the bracket 68. The substrate 40 is also fixed to the bracket 68. The hollow extension tube 66 has a through hole 70 at the lower end thereof, and a through hole 72 at the end extending from the drum 64. In this way, the discharge hose 24 extends outward from the upper through-hole 72 through the lower through-hole 70 and the hollow extension pipe 66, where the coupling 74 is fixed to the outer surface of the hollow extension pipe 66 by the lock ring 76. It is connected to.

Further, the hollow extension tube 66 has another set of openings 78 at the lower end, and these openings are formed at a position slightly above the connection portion to the cylinder 12. Therefore, the hollow extension tube
Since 66 is sealed at the upper end of the cylinder 12, the drum
Even if the liquid at 64 is depleted (or the liquid level is below the level above the cylinder 12), the liquid is still present where the piston 28 extends outside the cylinder 12. In this way, a liquid seal is formed at the upper end of the cylinder 12 so that air or steam does not enter the pump (except when the drum 64 is replaced), so that the metal hydroxy compound between the piston and the inner wall of the cylinder is removed. Generation is avoided. Therefore, an oil seal that may interfere with the operation of the pump is not required. Also, a device for maintaining sufficient hydraulic pressure is not required.

Clearly, an opening 78 is formed at a height high enough to form the above-mentioned seal, which also allows for liquid drainage during drum replacement.

As shown in FIG. 1, the drum 64 has at its upper end a through hole 80 through which a hollow extension tube 66 extends,
The hollow extension tube 66 is fixed to the drum 64 at this point. More specifically, the through hole 80 of the drum 64 has a bond screw 82, and a bond cap 84 with an external thread engages the bond screw 82 to provide a seal for the through hole 80.
It is arranged in a surrounding relationship with the hollow extension tube 66. The lock ring 85 is fixed to the hollow extension tube 66 directly above the bond cap 84 by a bolt 86, and the lock ring 88 is fixed to the hollow extension tube 66 immediately below the bond cap 84 by a bolt 90. As described above, the bond cap 84 is fixed to the hollow extension tube 66, and the hollow extension tube 66 is fixed to the drum 64.

A pipe closing member 92 is disposed in the upper end of the hollow extension pipe 66,
It is secured to this by bolts 86. The bolt 86 is also used for fixing the lock ring 85 to the hollow extension tube 66 as described above. The pipe closing member 92 is provided with an axially extending central hole 94 for passing the extension shaft 60 and another axially extending opening 96 for passing the discharge hose 24.

As also shown in FIG. 1, the bracket plate 98 is coaxially secured in the upper end of the hollow extension tube 66 by bolts 100, which secure the coupling 74 to the outer surface of the hollow extension tube 66. It is also used for A drive bearing 102 is secured to the bracket plate 98 and surrounds the shaft 56 to allow the shaft 56 to rotate and reciprocate therein.

However, as described above, the gas contained in the fluid,
For example, air, hydrogen, carbon dioxide and the like are often released into the pump chamber of cylinder 12 as a result of fluid agitation or changes in pressure and temperature during pump operation. Therefore, the released gas forms bubbles, and the bubbles are trapped in the pump chamber of the cylinder 12 so that the pump 10
Under certain circumstances, especially when the pump is operating at less than its maximum capacity, i.e., when the drive shaft 38 is attached to the shaft 56 at an angle less than its maximum degree. On the other hand, when it turns, the flow is completely blocked.
In general, the gas bubble is formed by recesses 34 in the piston 28 and the inner wall of the cylinder 12, as shown in more detail in the U.S. patent application by the same assignee, the entire disclosure of which is incorporated herein by reference. Trapped during

The U.S. patent application addresses this problem by overcoming an axis 56
Provides a configuration for shifting the retracted position and the extended position of the piston 28 in the cylinder 12 without changing the piston stroke for any angular displacement of the drive shaft 38 relative to. Therefore, the problem of gas trapping is eliminated with a constant flow rate.

Specifically, as shown in FIG. 2, substrate 40 has two elongated, slightly arcuate slots 104, 106,
These slots extend in the general direction of a centerline 108 extending along the axis of extension shaft 60 and piston 28, and slots 104, 106 are located on either side of centerline 108.

The friction plate 110 to which the yoke 46 and the motor 36 are fixed has two pivot pins 113 and 115 (shown by broken lines in FIG. 2), and these pivot pins are in respective slots 104 and 115.
Fits in 106. Therefore, the motor 36 is rotated (this is achieved by holding the grip 112 fixed to the substrate 40 and
6 is driven), the yoke 46 is relatively rotated with respect to the shaft 56 by the aforementioned ball and socket joint. Therefore, the pump stroke changes. This pump stroke can be measured by a scale 114 and a pointer 116 adjacent to the gripper 112.

Generally, the distance between the pivot pins 113 and 115 is
The center of ball 58 during one revolution of is approximately equal to the diameter of the circle passing.

The above-mentioned problems associated with the entry of air into the working chamber in the cylinder of a conventional pump are avoided by the arrangement described above.

Although the present invention has been described above with reference to specific embodiments, the present invention can be embodied in various forms other than this embodiment, and thus, the above-described specific configuration is merely an example and limits the present invention. Not something.

Claims (6)

(57) [Claims] 1. A cylinder means capable of being completely submerged in a liquid, said cylinder means having a working chamber defined by a working lower end, an inlet port, and a discharge port; Piston means capable of simultaneously rotating and reciprocating between a retracted position and an extended position within said cylinder means for pumping liquid to a port, said free end being disposed within said working chamber; Wherein said free end has a recess for alternately communicating a liquid to said inlet port and said outlet port; a driving means for driving said piston means; and A rotating assembly rotatably connected to the driving means for driving the piston means to be rotatable and reciprocally movable; and connecting the rotating assembly to the piston means. And an extension means for disposing the driving means and the rotating assembly outside the liquid, comprising: an extension shaft connecting the rotating assembly and the piston means; and a hollow extension tube surrounding the extension shaft. Said extending means, said hollow extending pipe having a lower end sealed to the upper end of said cylinder means in a sealing manner, and further, when the liquid level of said liquid falls below the upper end of said cylinder means, said cylinder means Wherein the hollow extension tube has an opening slightly above the seal fixing portion in order to maintain a liquid-tight state at the upper end of the submersible piston pump. 2. The apparatus according to claim 1, further comprising a hose connected to said discharge port of said cylinder, said hollow extension having openings at lower and upper ends thereof for passage of said hose through said hollow extension. A submersible positive displacement piston pump according to claim 1. 3. A yoke having a socket coupled to said drive means, arm means connected to said extension shaft and extending laterally, and a ball mounted on said arm means and fitted with said socket. 2. A submersible positive displacement piston pump according to claim 1, comprising a rotating assembly. 4. The apparatus according to claim 1, wherein said liquid is contained in a container having an opening at an upper end portion, and said extension tube extends through said opening and has means for connecting said extension tube to said container. 2. The submersible positive displacement piston pump according to claim 1. 5. A means for guiding the drive means during the rotational movement of the drive means so as to ensure that the recess is completely located in the working chamber when the piston means is in the extended position. 3. The submersible positive displacement piston pump according to claim 1, further comprising: 6. The guide means comprises two circular arcs slightly curved in the direction of the center line on either side of the center line of the pump on either the drive means or the substrate on which the drive means is mounted. The slot which is provided, and the other of the drive means or the substrate on which the drive means is mounted, on which the slot is not provided, has two pin means to be fitted with the respective slots. An underwater positive displacement piston pump according to claim 5.