KR101053856B1 - Piston for reciprocating pump - Google Patents

Abstract

The present invention relates to a piston for a reciprocating pump, the main configuration of which is a piston configured to reciprocate in a cylinder of a reciprocating pump, comprising: a core having a support flange protruding from an intermediate portion of an outer circumferential surface of the body; A first packing ring inserted to surround one side of the outer circumferential surface of the core body and supported axially by the support flange; And a second packing ring inserted to surround the other side of the outer circumferential surface of the core body and supported axially by the support flange, wherein the first packing ring is formed between the first hydraulic groove and the outer circumferential surface of the core body. The second packing ring is spaced apart to form a second hydraulic groove between the outer circumferential surface of the core body and forming a reciprocating motion in the cylinder. Since only the pressure side of the piston is in close contact with the inner circumferential surface of the cylinder, frictional resistance can be reduced. Therefore, the driving energy of the pump can be prevented, and even if the packing ring expands due to frictional heat or chemical reaction with the fluid, Since the pressure is not increased, the energy efficiency of the pump power source can be improved.

 Reciprocating, Pump, Piston, Packing Ring, Hydraulic Groove

Description

Piston for a reciprocating pump

The present invention relates to a piston for a reciprocating pump, and more particularly, to improve the lubrication and durability performance of the piston and thereby the energy efficiency of the reciprocating pump by improving the structure of the piston pumping the fluid in the reciprocating pump through the reciprocating motion. It relates to a piston for a reciprocating pump.

In general, a reciprocating pump is a pump configured to pump a fluid contained in a cylinder by reciprocating in a cylinder by rotating a crank connected to a piston in a pump cylinder through a piston rod. The pump is roughly shaped as shown in FIG. 1.

This reciprocating pump, as indicated by reference numeral 110 in FIG. 1, includes a cylinder 111 containing fluid and a piston connected to a power source via a piston rod 113 to reciprocate within the cylinder 111 ( 101, wherein the cylinder 111 is a cylindrical hollow body configured to receive a fluid therein, the fluid being supplied to or from the fluid supply source to the front and rear sides to send the fluid inside to the target point. The outlet inlet is formed, the fluid outlet formed at the front end is controlled by the front discharge valve 112, the fluid inlet is opened and closed by the front inlet valve 114, the fluid inlet and outlet formed at the rear end is also the rear suction and discharge valve Opening and closing control by 116 and 118, respectively.

On the other hand, the piston 101 is to reciprocate in the cylinder 111 is a piston body 123 constituting the body, the support bushing 124 interposed between the body 123 and the piston rod 113, and the piston Bar body including a fixing nut 149 for fixing the body 123 to the piston rod 113, the piston body 123 is made of, for example, a high elastic rubber material to be in close contact with the cylinder inner peripheral surface (115).

However, the conventional piston 101 in which the piston body 123 is made of high elastic rubber as described above is not only used in a general low pressure pump but also in a high pressure pump to which a high pressure operating pressure is applied. In order to maintain the sealing performance according to the outer diameter of the piston body 123 larger than the inner diameter of the cylinder 111 to ensure that the piston body 123 in the cylinder 111 bar bar, the piston body during operation of the pump 110 Since the 123 is always in close contact with the inner circumferential surface of the cylinder 111 at a high pressure, a substantial portion of the driving force input from the power source is extinguished due to the frictional resistance applied between the outer circumferential surface of the piston body 123 and the inner circumferential surface of the cylinder 115, so that There was a problem that the energy efficiency of the power source that is determined according to the ratio of the effective driving force used for pumping is greatly reduced.

Moreover, when the pump 110 is continuously operated for a long time or idling without fluid supply, and thermal expansion occurs due to friction from both front and rear end portions of the outer circumferential surface of the piston body 123, or the fluid is a material of the piston body 123, i.e. When the piston body 123 reacts with the fluid and expands due to excellent reactivity with rubber, the interference between the outer circumferential surface of the piston body 123 and the cylinder inner circumferential surface 115 becomes more severe, that is, the piston body 123 is Since the adhesion to the cylinder inner circumferential surface 115 more strongly, the energy efficiency of the power source due to the frictional resistance is further deepened, there was a problem that the damage to the rubber piston body.

In addition, as the frictional resistance applied to the piston body 123 increases in this way, the piston 101 has a lower durability and shorter service life, and in the case of long-term use, the abrasion of the outer circumferential surface of the piston body 123 is also quickly and broadly expanded. There was also a problem that caused a further power loss by the pressure generated by the pressing force for pressing the fluid in the cylinder 111 by 101.

The present invention has been proposed to solve the problems of the conventional reciprocating pump piston as described above, it occurs during the reciprocating motion by the packing ring fitted to the outer circumferential surface of the reciprocating pump in close contact with the inner circumferential surface of the cylinder only when pressurized fluid in the cylinder The purpose is to reduce the power required to operate the pump by reducing the frictional resistance with the inner circumferential surface of the cylinder.

In addition, the present invention is to minimize the power loss caused by the expansion of the packing ring by allowing the expansion of the packing ring swelling due to thermal expansion or the chemical reaction with the fluid is absorbed in the piston due to the frictional resistance as described above. There is another purpose.

In addition, the present invention improves the endurance life of the piston itself by minimizing the wear of the packing ring caused by friction with the cylinder inner circumferential surface as described above, while reducing the pressure loss of the power source generated in the piston while the packing ring is worn energy Another aim is to improve efficiency.

Accordingly, the present invention, in order to achieve the above object, in the piston which is to reciprocate in the cylinder of the reciprocating pump, the hollow cylindrical through which the shaft hole is passed along the axis to be coupled to the free end of the piston rod of the reciprocating pump A core formed in a body and having a support flange protruding from a middle portion of an outer circumferential surface of the body; A first packing ring inserted to surround one side of the outer circumferential surface of the core body and supported axially by the support flange; And a second packing ring which is inserted to surround the other side of the outer circumferential surface of the core body to face the first packing ring, and is supported in the axial direction by the support flange. The first packing is spaced apart from the outer circumferential surface of the core body so as to be pressurized by the fluid contained in the cylinder to be in close contact with the inner circumferential surface of the cylinder when moving to a top dead center of the second packing ring. Is spaced apart by forming a second hydraulic groove between the outer circumferential surface of the core body so as to be pressurized by the fluid contained in the cylinder to be in close contact with the inner circumferential surface of the cylinder when moving to the bottom dead center of the cylinder, And the second packing ring has the first largest amount of expansion due to frictional heat generated when it is in close contact with the inner circumferential surface of the cylinder. Such that the first and the increasing radial thickness to the bottom of the second pressure receiving groove gradually thickened at the outlet side of the second pressure receiving groove provides for the reciprocating piston pump with tapered.

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According to the piston for the reciprocating pump of the present invention, when the packing ring fitted to be oriented on both ends of the piston outer circumferential surface does not pressurize the fluid in the cylinder, it loosely contacts the inner circumferential surface of the cylinder and receives little frictional resistance against the inner circumferential surface of the cylinder. When pressurizing, the hydraulic groove formed between the packing ring and the core is resisted by the reaction of the fluid and expands radially outward so that the cylinder tightly adheres to the inner circumferential surface of the cylinder. Participation in the sealing compression of the can reduce the frictional resistance generated between the inner peripheral surface of the cylinder, and thus it is possible to reduce the driving energy of the pump to improve the energy efficiency of the power source.

In addition, even if the pump is used for a long time or idling, thermal expansion occurs in the packing ring due to frictional resistance with the inner circumferential surface of the cylinder, or the packing ring swells due to the chemical reaction between the packing ring and the fluid. Since the interval between the formed hydraulic groove is narrowed to absorb the expansion, the pressure applied to the packing ring is not increased due to the expansion as described above it is possible to suppress the power loss.

In addition, as seen above, even with the packing ring itself, wear and tear due to close contact with the inner circumferential surface of the cylinder can be greatly reduced, thereby extending the service life, and also caused by a gap between the piston and the cylinder due to the wear of the packing ring. By suppressing the pressure loss of the piston, it is possible to improve the energy efficiency of the power source.

Hereinafter, a piston for a reciprocating pump according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

The piston for the reciprocating pump of the present invention is composed of a core 3, a first packing ring 5, and a second packing ring 7, as shown in FIG. 2 to FIG. As shown in 2. For example, a piston is reciprocally mounted in the cylinder 11 of the pump 10 to be applied to the double-acting reciprocating pump 10, etc. First, the core 3 is a piston as shown in Figs. As a part of the frame | skeleton of (1), it is preferable to be made from a metal material with high rigidity so that it may have sufficient intensity | strength enough to support the pressure applied to the inside of the cylinder 11 of the reciprocating pump 10.

The core 3 also consists of a body 23 formed in a hollow cylindrical shape similar to the piston 1, which body 23 combines the first and second packing rings 5, 7 at both front and rear outer ends thereof. The rod-shaped piston rod 13 has an outer diameter smaller than the inner diameter of the cylinder 11 so that the cylinder 11 can be fitted in the state, and the shaft hole 21 penetrates along the axis to be connected to the power source of the reciprocating pump 10. The piston rod 13 inserted into the shaft hole 21 of the body 23 is fixed to the piston 1 by a fixing nut 49 fastened to the free end of the distal end portion.

Further, the core 3 has a cylindrical shape having an outer diameter close to the inner diameter of the cylinder 11 so as to be adjacent to the inner circumferential surface 15 of the cylinder, leaving only the minimum annular clearance space G between the inner circumferential surface 15 of the cylinder 11. The support flange 27 protrudes radially in the middle of the outer circumferential surface 25 of the core body 23, where the support flange 27 is capable of supporting the performance of the first and second packing rings 5, 7. In order to increase, it is best that the outer diameter matches the inner diameter of the cylinder 11, but since the outer circumferential surface of the support flange 27 should not contact the inner circumferential surface 15 of the cylinder, the inner diameter of the cylinder should be as close as possible to the extent that such contact does not occur. It is preferable to determine the outer diameter so that it is.

On the other hand, the first packing ring 5 is a sealing means made of a material of high elasticity, such as rubber, as shown in Figures 2 to 4, that is, at one end of the core 3, that is, shown in FIG. As shown in the drawing, the left end of the core 3 is fitted so as to surround the outer circumferential surface 25 of the core body 23, and the inner surface is supported in the axial direction by the support flange 27 protruding in the middle of the body 23.

At this time, the first packing ring 5 pressurizes the fluid contained in the front chamber 17 when the piston 1 moves toward the top dead center of the cylinder 11, that is, when the core 3 moves to the left side of FIG. 2. While being spaced apart from the outer peripheral surface 25 of the body 23 of the core 3 so as to be in close contact with the inner peripheral surface 15 of the cylinder 11 by the resistance of the fluid generated while forming an annular first hydraulic groove 29 have.

In addition, the second packing ring (7) is also a sealing means made of a material of high elasticity, such as rubber, like the first packing ring (5), which is oriented and mounted, as can be seen in Figures 2 to 4, the core 3 In the middle of the body 23, the first packing ring (5) on the opposite side end, that is, the right end of the core 3 in the case of Fig. 2 to surround the outer peripheral surface 25 of the core body (23) The inner surface is supported in the axial direction by the protruding support flange 27.

At this time, the second packing ring 7 also has a fluid contained in the rear chamber 19 when the piston 1 moves toward the bottom dead center of the cylinder 11, that is, when the core 3 moves to the right side of FIG. 2. An annular second hydraulic groove 31 is formed between the core body 23 and the outer circumferential surface 25 so as to be in close contact with the inner circumferential surface 15 of the cylinder 11 due to the resistance generated while being pressed.

However, the first and second packing rings 5 and 7, which form the first and second hydraulic pressure grooves 29 and 31 between the core 3, are separated from the respective outer ends 45 and 47. Tapered radially thicker until the bottom of the first and second hydraulic grooves (29, 31), the outer end (45, 47) with the most friction by close contact with the cylinder inner peripheral surface (15) Although the expansion amount increases due to frictional heat, the radial thicknesses of the packing rings 5 and 7 are generally balanced so that the first and second hydraulic grooves 29 and 31 are not blocked.

Further, the first and second packing rings 5, 7 may be wound around the outer circumferential surface 25 of the core body 23 in a number of different ways, and coupled to the outer body 25 of the core body 23, as shown in this embodiment of the core body 23. Annular engaging projections 51 and 53 are formed at both front and rear ends of the outer peripheral surface 25, and the respective inner peripheral surfaces (25) on the outer peripheral surface 25 of the core body 23 recessed by the engaging projections 51 and 53 are formed. 55, 57) can be fitted in close contact.

Now, the operation of the piston 1 for the reciprocating pump according to the preferred embodiment of the present invention configured as described above will be described.

The piston 1 for the reciprocating pump of the present invention is effectively used mainly in a double acting reciprocating pump 10, as shown in FIGS. 2, 5, and 6. Accordingly, the piston 1 pressurizes the fluid contained in the front chamber 17 while advancing together when the piston rod 13 is advanced by the power source as shown in FIG. 5, so that the front discharge valve 12 is While opening and discharging the fluid contained in the front chamber 17 out of the pump 10, negative pressure is generated in the rear chamber 19 to open the rear intake valve 16 and inflow fluid from the fluid supply source. At this time, the front suction valve 14 and the rear discharge valve 18 are kept closed.

On the contrary, as shown in FIG. 6, the piston 1 for the reciprocating pump of the present invention retreats together when the piston rod 13 reverses to pressurize the fluid contained in the rear chamber 19, and thus the rear discharge. The valve 18 opens to discharge the fluid contained in the rear chamber 19 out of the pump 10. At the same time, since a negative pressure is generated in the front chamber 17, the fluid is introduced from the fluid supply source while the front suction valve 14 is opened. At this time, the front discharge valve 12 and the rear suction valve 16 is kept closed.

As such, the piston 1 transfers the fluid supplied from the fluid source to the target point by repeating the reciprocating motion in the cylinder 11, and when moving toward the top dead center as shown in FIG. Due to the resistance of the fluid being pressurized in the front chamber 17 as shown in detail at A, the first hydraulic groove 29 of the first packing ring 5 is pressurized, thus pressing radially outwardly. The first packing ring 5 is expanded radially outward so that the outer circumferential surface 35 is in close contact with the cylinder inner circumferential surface 15. Thus, the piston 1 can pressurize the fluid in the front chamber 17 without pressure loss due to the pressure drop. At this time, since the second packing ring 7 maintains loose contact with the cylinder inner circumferential surface 15 while the piston 1 moves forward, the second packing ring 7 may be brought into close contact with the cylinder inner circumferential surface 15. This can prevent unnecessary power loss.

In contrast, when the piston 1 advances toward the bottom dead center as in FIG. 6, the second packing ring 7 is due to the resistance of the fluid being pressurized in the rear chamber 19 as shown in detail in FIG. Since the second hydraulic groove 31 of the pressure is received, the second packing ring 7 which is pressed radially outward is expanded radially outward so that the outer circumferential surface 37 is in close contact with the cylinder inner circumferential surface 15, It is possible to pressurize the fluid in the rear chamber 19 without pressure loss. At this time, since the first packing ring 5 maintains a loose contact with the cylinder inner circumferential surface 15, it eliminates unnecessary power loss that may occur when it is in close contact with the cylinder inner circumferential surface 15.

In addition, the piston 1 is heated from the front end of the outer circumferential surfaces 35 and 37 by repeatedly contacting and heating the first packing ring 5 to the cylinder inner peripheral surface 15 when the first packing ring 5 is moved forward and the reverse direction. Even if the volume is thermally expanded or if the first and second packing rings 5 and 7 are made of rubber, the volume expansion causes the first and second hydraulic grooves 29 and 31 to be expanded due to the reaction due to the chemical nature of the fluid. It is shifted toward and absorbed in the direction to narrow the gap between the first and second hydraulic grooves (29, 31), it is possible to prevent additional power loss due to thermal expansion of the first and second packing rings (5, 7). .

1 is a longitudinal sectional view showing a conventional reciprocating pump.

Figure 2 is a longitudinal sectional view of the reciprocating pump to which the piston according to the present invention is applied.

3 is an enlarged longitudinal sectional view of the piston shown in FIG. 2;

4 is a cross-sectional view of FIG. 3.

FIG. 5 is a view showing the reciprocating pump shown in FIG. 2 compressed to a top dead center; FIG.

FIG. 6 is a view in which the reciprocating pump shown in FIG. 2 is compressed to a bottom dead center; FIG.

Description of the Related Art

1: piston 3: core

5, 7: first and second packing ring 10: reciprocating pump

11: cylinder 12, 18: front and rear discharge valve

13: piston rod 14, 16: front and rear suction valve

15: cylinder inner peripheral surface 17, 19: front and rear chamber

23 core body 27 support flange

29, 31: first and second hydraulic groove

Claims (2)

delete In the piston (1) adapted to reciprocate in the cylinder (11) of the reciprocating pump (10), Is formed of a hollow cylindrical body 23 through which the shaft hole 21 is passed along the axis to be coupled to the free end of the piston rod 13 of the reciprocating pump 10, the outer peripheral surface 25 of the body 23 in the middle A core 3 on which a support flange 27 protrudes; A first packing ring 5 inserted to surround one side of the outer circumferential surface 25 of the body 23 of the core 3 and supported axially by the support flange 27; And A second packing ring 7 which is inserted to surround the other side of the outer circumferential surface 25 of the body 23 of the core 3 so as to face the first packing ring 5 and is axially supported by the support flange 27. ); The first packing ring 5 is pressurized by the fluid contained in the cylinder 11 when the core 3 moves to the top dead center of the cylinder 11 to closely adhere to the inner circumferential surface 15 of the cylinder 11. Spaced apart so as to form a first hydraulic groove 29 between the core 3, the outer circumferential surface 25 of the body 23, The second packing ring 7 is pressurized by the fluid contained in the cylinder 11 when the core 3 moves to the bottom dead center of the cylinder 11 to the inner peripheral surface 15 of the cylinder 11. The second hydraulic groove 31 is spaced apart from the outer circumferential surface 25 of the core body 23 so as to be in close contact with each other. The first and second packing rings 5 and 7 are formed at the outlet side of the first and second hydraulic grooves 29 and 31 having the greatest amount of expansion due to frictional heat generated when the first and second packing rings 5 and 7 are in close contact with the inner circumferential surface 15 of the cylinder. Piston for reciprocating pump, characterized in that the tapered so that the radial thickness gradually increases toward the bottom of the first and second hydraulic grooves (29, 31).

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