JPH11351150A - Reciprocating pump and its maintenance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reciprocating pump with a less replacement frequency of plunger and ease of maintenance and a maintenance method for the reciprocating pump capable of reducing the replacement frequency of the plunger. SOLUTION: A reciprocating pump includes a case 12 for holding the pressure of fluid at its inside B, a plunger 11 having a columnar outer periphery 11S for performing reciprocating motion in the longitudinal direction in a preset relatively positional relationship to the case 12 and a seal member 13 mounted on the case 12 so as to slide on the columnar outer periphery 11S of the plunger 11 for sealing fluid tending to leak between the case 12 and the plunger 11, the preset relatively positional relationship of the plunger 11 being changeable. Since the relatively positional relationship of the plunger 11 to the case 12 is changeable, the sliding position on the columnar outer periphery 11S where the seal member 13 mounted on the case 12 slides with the plunger 11 can be shifted to the longitudinal direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reciprocating pump and a maintenance method thereof, and more particularly to a reciprocating pump for increasing the pressure of a liquid to a high pressure and a maintenance method thereof.

[0002]

2. Description of the Related Art A crank type reciprocating pump as shown in FIG. 3 is used to generate high-pressure water used for a cleaning operation of mechanical parts. The crank type reciprocating pump converts the rotational motion of a driving device such as a motor or an engine not shown in FIG. 3 into reciprocating motion by a crank shaft not shown, and reciprocates the plunger 1 or the piston by a predetermined stroke S in the longitudinal direction. Exercise (C1, C2) to extrude the liquid.
In this manner, a high discharge pressure can be generally obtained while the discharge amount is small.

As shown in FIG. 3, this pump has a seal 3 between a vertically arranged plunger 1 and a pressure-holding case 2 so as to prevent pressurized high-pressure water from leaking. In the drawing, the upper side of the seal 3 is the atmosphere side A, and the lower side of the seal 3 and the lower side of the plunger 1 are the high pressure side B. The seal 3 is worn by sliding of the plunger 1, and the plunger 1 is also worn. In FIG. 3, only the structure around the plunger 1 and the case 2 is shown, and the other components are not shown.

The plunger 1 reciprocates with a stroke S between a top dead center (suction end) (shown by a solid line) and a bottom dead center (discharge end) (shown by a two-dot chain line). When the plunger 1 repeats this reciprocating motion, the leakage from the seal portion increases due to the deterioration of the seal 3. Conventionally, the plunger and the seal have been replaced when water leakage has started.

[0005]

According to the above-described conventional reciprocating pump maintenance method, when water leaks, the plunger and the seal are exchanged. Generally, after the seal is exchanged a plurality of times, the plunger and the seal are exchanged. The plunger had been replaced. But,
If only the seal is replaced without replacing the plunger, the life of the seal tends to decrease with each replacement. This is because the plunger also wears out and the sealing performance gradually decreases, so that the expensive plunger eventually needs to be replaced quite frequently.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a reciprocating pump in which plunger replacement frequency is low and maintenance is easy, and a reciprocating pump maintenance method in which plunger replacement frequency is low.

[0007]

In order to achieve the above object, a reciprocating pump according to the first aspect of the present invention, as shown in FIG.
2; a plunger 11 having a cylindrical outer peripheral surface 11S and reciprocating S in a longitudinal direction with a predetermined relative positional relationship with respect to the case portion 12 to increase the pressure of the fluid; and a cylindrical shape of the plunger 11. A sealing member 13 attached to the case portion 12 so as to slide on the outer peripheral surface 11S, and configured to seal the fluid that leaks between the case portion 12 and the plunger 11;
Is configured to be changeable.

With such a configuration, the relative position of the plunger 11 with respect to the case portion 12 can be changed, so that the sealing member 13 attached to the case portion 12 slides on the plunger 11 in a cylindrical outer peripheral surface. 11S
Can be shifted in the longitudinal direction.

The reciprocating pump includes a rod 31 for driving the plunger 11; and a connecting portion 30 for connecting the plunger 11 and the rod 31, as described in claim 2. And a detachable plate 34 for defining a relative position between the rod 31 and the rod 31.

In this configuration, since the plate 34 is provided, the relative position between the plunger 11 and the rod 31 is changed by attaching and detaching the plate 34. Therefore, the cylindrical outer peripheral surface 11S in which the sealing member 13 slides on the plunger 11 is provided. Can be shifted in the longitudinal direction.

To achieve the above object, a maintenance method for a reciprocating pump according to the third aspect of the present invention includes a sealing member 13 provided on a case 12 as shown in FIG.
Is configured to slide with a plunger 11 having a cylindrical outer peripheral portion 11S that reciprocates relatively in the longitudinal direction with respect to the case portion 12 to seal between the plunger 11 and the case portion 12. In the method for maintaining the reciprocating pump, the sliding position of the seal member 13 with respect to the plunger 11 is moved after a predetermined time of operation.

Here, the operation after the predetermined time of operation may be, for example, when the leakage from the seal portion has reached an allowable limit, or the time until the leakage reaches the allowable limit is determined by the discharge pressure or the fluid. May be determined statistically or in design according to the operating conditions such as the type of the device, and the time may be set as a predetermined time. The operation time set for the tortoise may be set as the predetermined time.

In order to move the sliding position of the seal member 13 with respect to the plunger 11, the plunger 11 may be moved with respect to the case portion 12 in the longitudinal direction, or the seal member 13 may be attached to the case portion 12. The position may be moved.

According to such a maintenance method, since the sliding position of the seal member 13 with respect to the plunger 11 is moved after the operation for a predetermined time, the relative positional relationship in which the seal member 13 slides with the plunger 11 is changed. , Plunger 1
The sliding portion with the first seal member 13 is shifted.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same or corresponding members are denoted by the same or similar reference numerals, and duplicate description is omitted.

FIG. 1 is a sectional view of a reciprocating pump according to a first embodiment of the present invention. In the figure, a plunger 11 having a cylindrical shape and a thick rod shape is placed in a case portion 12.
It is held so as to be able to reciprocate in the longitudinal direction. Case part 1
Between the plunger 2 and the plunger 11, an annular bearing 15 for guiding the reciprocating motion of the plunger 11 in the longitudinal direction, an annular seal member 13, an annular first seal retainer 16, a compression coil spring 18, and an annular second seal retainer 17 are provided. Are loaded in this order from the atmosphere side A to the pressure side B. The bearing 15 is pressed by the ground presser 19 on the atmosphere A side,
It is fixed relatively to case part 12.

The bearing 15 and the second seal retainer 17 are configured to be fixed relatively to the case 12 in the longitudinal direction of the plunger 11. Seal member 13
In the embodiment of FIG. 1, three ring-shaped packings 13a to 13c each having a substantially square cross section are provided. A space ring 14a is provided between the packings 13a and 13b, and a space ring 14a is provided between the packings 13b and 13c. Is the space ring 14b
However, a space ring 14c is mounted between the packing 13c and the first seal retainer 16, respectively. As the packing, for example, a square packing in which hemp is impregnated with a Teflon resin is used. The number of packing is not limited to three as shown in FIG. 1 and may be one or more.

The compression coil spring 18 has one end in contact with the end face of the second seal retainer 17 and the other end in the first position.
It is in contact with the end face of the seal holder 16. In this way, the seal member 13 is pressed against the end face of the bearing 15 in the longitudinal direction of the plunger 11 by the first seal retainer 16 to provide a sealing effect. Space ring 14a ~
The thickness in the longitudinal direction of 14c is about 1/3 of the longitudinal dimension of the packings 13a to 13c in the initially loaded state.

The case 12 described above is housed in the bracket 20. The case portion 12 and the bracket 20 are relatively fixed in the longitudinal direction of the plunger 11. A cylinder case 22 having a suction port 21 and a discharge flange 24 having a discharge port 23 are connected to the bracket 20. The suction port 21 and the pressure space B are separated from each other by a one-way valve mechanism, and the pressure space B and the pressure are separated from the suction port 21 side as the plunger 11 reciprocates. It is configured such that a flow is formed from the space B to the discharge port 23 side.

The case portion 12 between the bearing 15 and the atmosphere side A has a water inlet 25 for water injection into the ground,
A water injection outlet 26 is provided.

Further, as shown in FIG. 1, the rod 3 for driving the plunger 11 to reciprocate in the longitudinal direction.
1 is provided. The rod 31 is connected to a crankshaft (not shown), and the crankshaft is configured to rotate relative to the bracket 20 by a driving machine such as an electric motor or an engine (not shown).

As shown in detail in FIG. 2, the rod 31 and the plunger 11 are connected by a connecting portion 30 in a universal joint shape. Here, the end 11a on the connecting portion side of the plunger 11 is formed in a spherical shape. On the other hand, the end of the rod 31 on the connecting portion side has an external thread 31
a is formed, and a hollow 31b which is circular and is recessed in the longitudinal direction of the rod 31 is formed inside.

The connecting portion 30 further includes a male screw 31a.
And a female screw 36a screwed with the plunger tightening nut 36 formed on the inner surface. Plunger tightening nut 3
The female screw 6 is open in the longitudinal direction on the female screw 36a side, and is closed on the opposite side with an opening through which the plunger 11 can penetrate with a slight gap. On the closed side, the space between the plunger tightening nut 36 and the plunger 11 is sealed by an O (O) ring 37.

At the spherical end 11a of the plunger 11 on the connecting portion side, a first spherical seat 32 having a spherical depression 32a that matches the spherical surface is provided between the end 11a and the depression 31b and at the end. Spherical depression 33 compatible with the spherical surface of portion 11a
The annular second spherical seat 33 having an opening a passing through the plunger 11 is combined with the closed side of the plunger tightening nut 36. The first spherical seat 32 has a flat surface 32b on the side opposite to the spherical recess 32a, and a second spherical seat 3 similarly.
3 is formed on the flat surface 33b on the side opposite to the spherical recess 33a.

The annular second spherical seat 33 is provided on the plunger 11.
Can be assembled by inserting from the end opposite to the spherical end 11a.

Further, as shown in FIG. 2, in the present embodiment, first, a disk-shaped plate 34 having a thickness t is placed in the recess 31b of the rod 31 and the bottom of the recess 31b and the first spherical seat 3
It is inserted and set between the second plane 32b. The assembled state is as shown in FIG. On the other hand, a ring plate 35 having the same thickness t as the plate 34 is separately prepared.

After operating this reciprocating pump for a predetermined time, as shown in FIG.
Between the second spherical seat and the plunger tightening nut 36.
5 is inserted and installed. In this way, the plate 34,
The relative position of the plunger 11 with respect to the case 12 is changed by the thickness t of the ring plate 35. Consequently, the relative positional relationship between the sealing member 13 attached to the case portion 12 and the plunger 11 is shifted.

Here, the operation after the predetermined time has elapsed may be, for example, when the leakage from the seal portion has reached the allowable limit, or the time until the leakage reaches the allowable limit may be the discharge pressure or the discharge pressure. Depending on the operating conditions such as the type of fluid, etc., it may be determined statistically or based on the design based on the operation record, and the time may be set as a predetermined time, or may be slid preventively before the leakage becomes remarkable. An operation time set shorter than the time until the leakage reaches the allowable limit may be set as the predetermined time so that the movement position is shifted.

Here, the fact that the seal member 13 is attached to the case portion 12 means that the seal member 13 is fixedly attached to the case portion 12 in the longitudinal direction of the plunger 11. Yes, it is not always necessary to directly attach to the case portion 12, but it may be attached via some member.

The operation of the reciprocating pump according to the embodiment of the present invention having the above structure will be described with reference to FIG. In the drawing, when the rod 31 reciprocates in a stroke S with the rotation of a crankshaft (not shown), the plunger 11 is pushed into the case portion 12 through the connecting portion 30 and pulled out. Accordingly, the plunger 11 reciprocates in the case portion 12 with a speed change close to a sine wave and a positional stroke S close to the sine wave. That is,
At the beginning of the pushing (discharge stroke), there is little advance for the rotation angle of the crankshaft (not shown), and similarly, at the end of the discharge stroke, there is little advance. The same is true on the pull side (suction stroke).

FIG. 1 shows that the plunger 11 is
Is shown fully pressed. In this way, when the plunger 11 moves upward in FIG. 1 in the direction of C2, that is, in the suction direction, the handling liquid is sucked into the pressure space B from the suction port 21, and when the plunger 11 moves in the downward direction of C1, that is, in the discharge direction, Liquid discharge port 23
Is discharged at a high pressure.

The seal member 13 and the plunger 11 are worn out,
Wear occurs mainly during the discharge stroke where pressure is generated. This is because the pressure of the liquid causes the seal member 13 to be strongly pressed against the outer peripheral surface 11S of the plunger 11 during the discharge process.

Further, the amount of wear of the outer peripheral surface 11S of the plunger 11 is affected by the contact time with the seal member 13. That is, the plunger 11 should be more worn at positions corresponding to the first and last portions of the discharge.

However, since the liquid is used to compress the liquid in the pressure space B, which is the inside of the case, to the target pressure at the beginning of the discharge, the acting pressure is gradually increased without suddenly increasing to a high pressure. Since the plunger 11 moves during this time, wear is small.

On the other hand, at the end of the discharge, the abrasion is large because the moving speed of the plunger 11 is gradually reduced to zero while maintaining the high pressure. Even in this case, the wear does not occur uniformly on the entire sliding portion of the plunger 11 that is in contact with the seal member 13 when the moving speed becomes zero. Extreme wear is observed in the vicinity of the position of the plunger 11 (at the bottom dead center) located at the end of the discharge, in particular, from the end Q to the pressure side B up to the longitudinal width of the seal 13a, or about half thereof. The inventor has found that Other parts wear slightly.

When the plunger 11 is worn, the seal member 13 breathes in this portion, and the wear of the seal member 13 is accelerated, and the wear of the plunger 11 itself is promoted. Breathing occurs because the seal member 13 bites into the worn portion of the plunger 11 and changes its shape. Once the wear of the plunger 11 starts, the surface roughness of the plunger 11 deteriorates, so that the contact resistance between the plunger 11 and the seal member 13 increases, and the wear of the plunger 11 itself and the seal member 13 is promoted.

Here, before the plunger 11 reaches the use limit, the plate 34 shown in FIG. 2 is removed and the ring plate 35 is added, and the sealing member 13 of the plunger 11 is removed.
, The use duration can be extended. At this time, when the relative position is moved, the position of the plunger 11 is moved to the atmosphere A side, that is, to the outside of the seal member 13, so that the wear suppressing effect is higher. At this time, the outer peripheral surface 11S of the plunger 11 has a clearly annular wear mark at a position corresponding to the end Q of the seal at the bottom dead center, but the wear mark is displaced outward from the seal member 13.

However, since these wear marks have a slight depth of the order of microns, the ring plate 35 is assembled at first, and after the operation for a predetermined time, the ring plate 35 is replaced with the plate 34 so that the plunger 11 is moved inward. Even if it is shifted, the sealing effect can be obtained.

In the embodiment shown in FIGS. 1 and 2, the plate 3
4. The structure is such that only one ring plate 35 can be exchanged. However, several types of plates and ring plates each having a corresponding thickness are prepared (so that the total thickness of both is constant). If the relative position between the plunger 11 and the seal member 13 can be changed in stages, the use continuation time can be further extended.

FIG. 2A is a plan view of the ring plate 35, and FIG. If the ring plate 35 is formed as a half-split ring plate as shown here, the plunger 11 and the sealing member 13 can be disassembled without disengaging the plunger 11 from the case 12 in FIG. , The downtime (stop time) of the pump can be minimized.

Normally, the plunger 11 and the sealing member 13
During one change of the relative position with respect to the seal member 13
Exchange several times. Also, the outer peripheral surface 11 of the plunger 11
If the relative position between the plunger 11 and the seal member 13 is controlled before the remarkable wear mark is generated on the S or before the leakage from the seal portion becomes remarkable, the wear suppressing effect is further improved. Get higher.

With reference to FIG. 2, a specific operation for changing the relative position between the plunger 11 and the seal member 13 will be described. After the plunger 11 to be worked is adjusted to a position at the beginning of the discharge stroke (a position fully extracted as shown in FIG. 3), the screw of the plunger tightening nut 36 which is a connecting portion is loosened, and the plate 34 is removed. Take out. Next, the ring plate 35 is inserted between the spherical seat 33 and the plunger tightening nut 36, and the plunger tightening nut 36 is inserted.
Retighten. As a result of this operation, the portion with relatively little wear is discharged and shifted to the position of the end Q of the seal member 13 at the time of completion, so that the wear of the seal member can be delayed.

Furthermore, if the plunger 11 is made of a material having high wear resistance such as cemented carbide or ceramic, the frequency of changing the sliding position of the plunger 11 or the plunger 11
Can be replaced less frequently, and the continuous use time can be further extended.

The pressure of the high-pressure water as the handling liquid is 1500 kg
At f / cm ² (approximately 150 MPa) or more, the tendency to wear appears remarkably. Under such conditions, silicon carbide SiC, zirconia, etc. are particularly suitable among ceramics.

Instead of preparing the plate 34 and the ring plate 35, the spherical seats 32, 33 are prepared in a plurality of pairs having different thicknesses in the longitudinal direction (so that the total thickness is the same for each pair). 2), the pair may be replaced after the operation for a predetermined time.

A method for maintaining a reciprocating pump according to a second embodiment of the present invention will be described. In this embodiment, FIG.
In this reciprocating pump, after operating for a predetermined time, the relative position of the plunger 11 with respect to the case portion 12 is not changed, but the seal portion 13 is moved relative to the case portion 12.

One method for this is to use the bearing 15 and the first
A pair of seal holders 16 are prepared in a plurality of different lengths (so that the total thickness of each pair is the same), and when the packing 13 as a seal member is replaced, the pair is replaced. You may. Alternatively, an annular adjustment ring may be inserted and removed between the end of the bearing 15 on the atmosphere A side and the bearing 15 and the gland presser 19.

Further, the relative position can be changed by increasing the length of the bearing 15 within the range permitted by the compression spring 18. In particular, this method may be used if the change is made only once.
If the compression spring 18 cannot tolerate such an amount of compression, a compression spring whose free length is shortened by the length of the bearing 15 may be prepared. Conversely, the relative position can be changed by shortening the length of the bearing 15. At this time, if the compression force of the compression spring 18 is insufficient, a compression spring having a longer free length by the shortened bearing 15 may be prepared.

That is, the relative position of the seal 13a with respect to the plunger 11 can be shifted to the inside, that is, to a portion where the wear is relatively small, or to the outside where there is no wear. Thus, effects similar to those described in the first embodiment can be obtained.

As described above, according to the embodiment of the present invention,
Minimize the unavoidable plunger wear on high pressure reciprocating pumps, minimize seal and plunger replacement frequency, save on replacement and labor costs, and minimize pump downtime. Can be minimized.

[0051]

FIG. 2 shows an embodiment in which a plate 34 of 5 mm is used. The recommended thickness of the plate 34 is approximately the thickness of one seal 13a. In this case, a blade packing is used as the packing.

Alternatively, the plunger 11 corresponds to a crankshaft rotation angle of about 30 ° until the end of the discharge stroke.
Is appropriate. If the stroke S of the plunger is 100 mm, it is about 6 mm. In practice, the length of severe wear is about 10% of the plunger diameter.
This should also be taken into account.

In this embodiment, one-time adjustment is possible.
The service life of a batch can be extended in a short time. That is, it is possible to easily take measures to extend the life of the seal and the plunger by stopping the operation for a short time. Normally, wear occurs at places other than the end Q of the seal at the end of the discharge. Therefore, even if two or more measures are taken to extend the life, the effect of extending the life is not necessarily high. May be adjusted.

As described above, the plunger 11 and the case 1
The length of the plunger 11 can be extended only by configuring the length 2 by the relative position change amount of the plunger 11 and shifting the position where the plunger 11 slides with respect to the seal member 13.

[0055]

As described above, according to the present invention, the relative position of the plunger with respect to the case portion can be changed. Therefore, the reciprocating pump with low plunger replacement frequency and easy maintenance, and plunger replacement. It is possible to provide a method for maintaining the reciprocating pump, which can be reduced in frequency.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of a reciprocating pump according to a first embodiment.

FIG. 2 is an enlarged sectional view showing a disassembled state of a connecting portion of the reciprocating pump of FIG.

FIG. 3 is a sectional view showing a main part of a conventional reciprocating pump.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Plunger 12 Case part 13, 13a to 13c Seal 14a to 14c Space ring 15 Bearing 16 First seal retainer 17 Second seal retainer 18 Compression coil spring 19 Ground retainer 20 Bracket 21 Suction port 22 Cylinder case 23 Discharge port 24 Discharge flange Reference Signs List 30 connecting portion 31 rod 32 first spherical seat 33 second spherical seat 34 plate 35 ring plate 36 plunger tightening nut 37 O-ring

Claims (3)

[Claims] A case portion for holding the pressure of the fluid inside; a cylindrical outer peripheral surface; reciprocating with respect to the case portion in a predetermined relative positional relationship in the longitudinal direction, to thereby increase the pressure of the fluid; A plunger that is mounted on the case portion so as to slide on the cylindrical outer peripheral surface of the plunger, and is configured to seal the fluid that leaks between the case portion and the plunger. A reciprocating pump comprising: a sealing member provided with the plunger; and the predetermined relative positional relationship of the plunger is changeable. 2. A rod for driving the plunger; and a connecting portion for connecting the plunger and the rod; the connecting portion includes a detachable plate for determining a relative position between the plunger and the rod. The reciprocating pump according to claim 1, comprising: 3. A plunger having a cylindrical outer peripheral portion reciprocating in a longitudinal direction relative to the case portion slides on a seal member provided on the case portion, so that the plunger and the case portion are moved. A method for maintaining a reciprocating pump configured to perform a seal between the reciprocating pump and a sliding position of the seal member with respect to the plunger after a predetermined time of operation. Maintenance method.