JP2004092528A - Method for manufacturing slurry pumping pump and slurry pumping cylinder - Google Patents

Abstract

An object of the present invention is to improve the wear resistance of a slurry pumping cylinder so that it can be used for a longer period.
A slurry pumping cylinder, a piston capable of reciprocating in the slurry pumping cylinder, and a driving device reciprocating the piston in the slurry pumping cylinder are provided. A slurry pump for forming a suction part capable of suctioning and a discharge part capable of discharging slurry, wherein the suction part and the discharge part are provided in a switchable manner. A first layer 12 made of chromium cast iron is provided, and a second layer 13 made of carbon steel is provided outside the first layer 12.
[Selection diagram] Fig. 3

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a slurry pump and a slurry pump cylinder. More specifically, this slurry pumping pump includes a slurry pumping cylinder, a piston capable of reciprocating in the slurry pumping cylinder, and a driving device for reciprocatingly driving the piston in the slurry pumping cylinder. A cylinder is provided with a suction part capable of sucking slurry and a discharge part capable of discharging slurry, and the suction part and the discharge part are provided in a switchable manner.
[0002]
[Prior art]
The slurry pumping pump is capable of pumping a slurry made of, for example, concrete or mortar by sucking and discharging the slurry by a reciprocating piston with a slurry pumping cylinder.
For this reason, the inner peripheral surface side of the slurry pumping cylinder comes into direct contact with concrete or the like or a piston, so-called rubbing wear is extremely severe, and considerably high wear resistance is required.
[0003]
Therefore, conventionally, as a slurry pumping cylinder, one in which the inner surface of carbon steel is quenched to increase the hardness and the inner surface thereof is subjected to Cr plating (chrome plating) is used.
[0004]
[Problems to be solved by the invention]
However, in such a conventional apparatus, even if the hardness of carbon steel is increased, there is almost no effect on abrasion wear, and even a very thick Cr plating of about 0.3 mm is applied, for example, by rubbing. There is a problem that the wear resistance effect can be obtained only for a short period of time due to scratches or the like.
[0005]
The present invention has been made in view of the above circumstances, and has as its object to improve the wear resistance of a slurry pumping cylinder so that it can be used for a longer period of time.
[0006]
[Means for Solving the Problems]
The feature of the invention according to claim 1 is that a slurry pumping cylinder for slurry pumping, a piston that can reciprocate in the slurry pumping cylinder, and a driving device that reciprocates the piston in the slurry pumping cylinder. Along with
In the slurry pumping cylinder, a suction unit capable of sucking slurry, and a discharge unit capable of discharging the slurry are formed, and a slurry pump that has the suction unit and the discharge unit switchably provided,
The cylinder body has a first layer made of high chromium cast iron on the inner peripheral surface side, and a second layer made of carbon steel outside the first layer.
[0007]
(Function and effect)
According to this characteristic configuration, since the cylinder main body includes the first layer and the second layer, the piston is reciprocated in the cylinder main body by the driving device, and the suction unit and the discharge unit are arbitrarily switched. Can be maintained over a long period of time by sucking the slurry into the cylinder main body and feeding the sucked slurry out of the cylinder main body from the discharge section.
That is, since the cylinder body is provided with the first layer made of high chromium cast iron on its inner peripheral surface, the cylinder body has a high resistance to abrasion and the like caused by the high hardness chromium carbide (chromium / iron carbide) of the high chromium cast iron. Abrasion resistance can be expected. In addition, since the second layer made of carbon steel is provided outside the first layer, the drawback of the first layer made of high chromium cast iron is complemented by the toughness of carbon steel, and the cylinder body is sufficiently pumped under high pressure. It can be endurable. Furthermore, the second layer is advantageous because it is easy to process.
Therefore, the abrasion resistance of the cylinder body is improved, and the cylinder body can be used for a longer period of time than before. For example, it is not necessary to frequently perform maintenance such as replacement of the cylinder body, thereby improving workability and economy. it can.
[0008]
According to a second aspect of the present invention, in addition to the first aspect, the first layer and the second layer are metallurgically bonded.
[0009]
(Function and effect)
Since the first layer and the second layer are metallurgically (metallurgically) joined, the first layer having high wear resistance as described above and the second layer complementary to the first layer are used. The effect can be obtained more reliably.
Furthermore, since the first layer and the second layer are metallurgically bonded in this manner, the bond between the first layer and the second layer is strong. For example, the first layer has a thickness still smaller than that of the first layer. Although it is left, it does not peel off from the second layer, and the high wear resistance of the first layer can be obtained until the thickness of the first layer completely disappears, which is economical.
[0010]
According to a third aspect of the present invention, in addition to the first or second aspect, the hardness of the first layer is 500 HB or more.
[0011]
(Function and effect)
When the hardness of the first layer is 500 HB or more, appropriate wear resistance can be reliably obtained, which is preferable.
[0012]
According to a fourth aspect of the present invention, in addition to any one of the first to third aspects, the surface roughness of the inner peripheral surface of the first layer is 20S or less.
[0013]
(Function and effect)
If the surface roughness of the inner peripheral surface of the first layer is 20S or less, the inner peripheral surface of the first layer is appropriately smooth, so that the piston can be more smoothly reciprocated on the inner peripheral side, It is suitable.
[0014]
According to a fifth aspect of the present invention, there is provided a method of manufacturing a slurry pumping cylinder according to the third aspect,
Performing a main body forming step of providing a cylinder main body including the first layer and the second layer;
After subjecting the cylinder body to a heat treatment at 900 ° C. to 925 ° C., an air cooling treatment is performed to perform an adjustment step so that the hardness of the first layer is 500 HB or more.
After the adjustment step, finishing processing is performed on at least the inner peripheral surface of the first layer.
[0015]
(Function and effect)
In the adjusting step, the cylinder body including the first layer and the second layer provided in the body forming step is subjected to a heat treatment at 900 ° C. to 925 ° C., and is then subjected to an air-cooling treatment. By setting the hardness of the layer to 500 HB or more, it is possible to reliably manufacture a cylinder body in which the effect of the first layer having high wear resistance and the second layer complementary to the first layer can be obtained. .
Then, after the adjusting step, at least, by performing a finishing process on an inner peripheral surface of the first layer, a pressure-feeding cylinder capable of smoothly reciprocatingly sliding a piston on the inner peripheral side is manufactured. Can be.
[0016]
According to a sixth aspect of the present invention, in addition to the fifth aspect, in the adjusting step, heat treatment is performed at 900 ° C. to 925 ° C. for 1 hour or more.
[0017]
(Function and effect)
In the adjusting step, by performing a heat treatment at 900 ° C. to 925 ° C. for 1 hour or more, a cylinder capable of performing a finishing process on the inner surface side of the first layer while ensuring a stable and appropriate hardness. The body is obtained.
[0018]
According to a seventh aspect of the present invention, in addition to the fifth or sixth aspect, in the main body forming step, the cylinder main body is formed by centrifugal casting.
[0019]
(Function and effect)
According to the centrifugal casting method, a cylinder body in which the first layer and the second layer are metallurgically joined can be efficiently manufactured.
[0020]
According to a feature of the invention of claim 8, in addition to the feature of claim 5 or 6, in the main body forming step, after forming the second layer by centrifugal casting, the first layer is overlaid. It is formed by welding.
(Function and effect)
A material that is difficult to cast can be formed on the first layer by overlay welding.
[0021]
According to a ninth aspect of the present invention, in addition to the fifth or sixth aspect, the cylinder body is formed by the HIP method in the main body forming step.
[0022]
(Function and effect)
According to the HIP method, a cylinder body in which the first layer and the second layer are more uniformly metallurgically bonded can be manufactured.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0024]
1 to 3 show one embodiment of a slurry pump A according to the present invention.
As shown in the perspective view of FIG. 1, the pressure feed pump A includes, as an example, a pump body 10 and a suction / discharge switching unit 20 connected to the pump body 10, and is configured as follows.
[0025]
In the pump body 10, as shown in the figure, two slurry pressure feeding cylinders 11 (11a, 11b) are arranged side by side so that their respective axes are parallel to each other. The pumping cylinder 11a (11b) is provided so as to discharge the slurry, and the other pumping cylinder 11b (11a) is provided so as to suck the slurry.
[0026]
As shown in detail in the enlarged sectional view of FIG. 3, the slurry pumping cylinder 11 is formed in a two-layer pipe structure as an example, and the inner layer (corresponding to the first layer) 12 is made of high chromium cast iron and has a thickness of, for example, 3 mm. The outer layer (corresponding to the second layer) 13 is a layer made of carbon steel, for example, having a thickness of 8 mm.
[0027]
The inner layer 12 preferably has a hardness of 500 HB or more, and more preferably has a hardness of 530 to 690 HB, from the viewpoint of providing appropriate wear resistance. Further, the surface roughness of the inner surface of the inner layer 12 is preferably 20S or less, more preferably 6 to 15S, from the viewpoint of smooth reciprocal sliding of the piston 17 described later.
[0028]
In this embodiment, the inner layer 12 and the outer layer 13 are metallurgically (metallurgically) joined, and each has the following composition. The composition of the high chromium cast iron forming the inner layer 12 is C: 2.5 to 3.2% by weight and Cr: 23 to 30% by weight. The carbon steel forming the outer layer 13 is SC450 of a carbon steel cast steel product according to JIS standards, and its composition is C: 0.4 or less, P: 0.4 or less, and S: 0.04 or less.
[0029]
A steel flange 15 as a connecting member is attached to the outer peripheral side of each end of the slurry pumping cylinder 11 by welding or the like.
[0030]
One end (hereinafter, referred to as a rear end) of each of the slurry pumping cylinders 11 formed in this way is connected to a support plate 16 via a flange 15, and the support plate 16 is attached to each slurry pumping cylinder 11. The pump main body 10 is provided with a hydraulic cylinder device (an example of a driving device) 18 that drives the piston 17 to reciprocate and slide in the inside 11.
The opening 14 formed on the other end side (hereinafter, referred to as the front end side) of the slurry pumping cylinder 11 corresponds to a suction part capable of sucking slurry and a discharge part capable of discharging slurry. The switching unit 20 is connected.
[0031]
As shown in FIGS. 1 and 2, the suction / discharge switching unit 20 has a substantially rectangular connecting plate 23 connected to the hopper 21 and the outlet pipe 22, and is slidably mounted on the connecting plate 23. The connecting plate surface 23 and the sliding plate 24 are attached to each other with the plate surfaces facing each other.
[0032]
The connection plate 23 is provided with three through-holes penetrating in the thickness direction thereof, and the outlet pipe 22 is connected to a central one of the three through-holes. The two through-holes are connected via a suction pipe 26 to a hopper 21 capable of storing slurry.
[0033]
On the other hand, the slide plate 24 is provided with two through-holes which can communicate with the through-holes of the connection plate 23 by sliding movement to be described later. On the plate surface side, each slurry pumping cylinder 11 is connected to the two through-holes via a flange 15 or the like so as to maintain a posture in which the axial direction thereof is orthogonal to the plate surface of the slide plate 24. Installed.
[0034]
The slurry pumping cylinder 11 (pump body 10) attached to the slide plate 24 is connected to the slide plate 24 by slide drive cylinder devices 28a and 28b provided on both sides of the slide plate 24. When the position is switched as follows by the slide driving with respect to the use plate 23, each slurry pressure feeding cylinder 11 is switched between a state of sucking the slurry and a state of discharging the slurry.
[0035]
In other words, the sliding movement of the pump body 10 by the one cylinder device 28a causes one of the pumping cylinders 11a to be in communication with the outlet pipe 22 through the opening 14 so as to be able to discharge the slurry, and the other pumping cylinder 11b to open The first position is switched to a first position in which the slurry in the hopper 21 can be sucked by being communicated with the suction pipe 26 via 14 (see FIG. 2A). Then, by the sliding movement of the pump body 10 by the other cylinder device 28b, one of the pressure feeding cylinders 11a is communicated with the suction pipe 26 through the opening 14 so that the slurry in the hopper 21 can be sucked. 11b is switched to the second position where it is in communication with the outlet pipe 22 through the opening 14 so that the slurry can be discharged (see FIG. 2B).
By switching the position between the first position and the second position, the opening 14 of each of the pressure feeding cylinders 11a and 11b is configured to be freely switchable to a suction part capable of sucking slurry and a discharge part capable of discharging slurry. ing.
[0036]
In the slurry pumping pump A configured as described above, one of the pumping cylinders 11a (11b) sucks the slurry in the hopper 21 by sliding the piston 17 by the hydraulic cylinder device 18, and the other pumping cylinder. At 11b (11a), the slurry is discharged from the opening 14 to the outlet pipe 22 by the sliding of the piston 17 by the hydraulic cylinder device 18, and the slurry can be sent under high pressure at a pressure of about 80 kg / cm2. I have.
[0037]
Next, an example of a method for manufacturing the slurry pumping cylinder 11 of the slurry pumping pump A described above will be described.
[0038]
1) First, a main body forming step is performed as follows to form a cylinder main body constituting the slurry pressure feeding cylinder 11.
[0039]
In the present embodiment, as an example, a molten metal of carbon steel having the above-described composition is first injected into a cylindrical mold that rotates at a high speed by centrifugal force casting, and is spread on the inner surface of the mold by the action of centrifugal force. While the outer layer 13 is formed by being solidified while being pressed, a molten metal of high chromium cast iron having the above-described composition is poured into the inner surface of the outer layer 13, and the inner layer 12 is solidified by being similarly extended and pressed against the inner surface of the outer layer 13. By forming, it is assumed that the inner layer 12 and the outer layer 13 are metallurgically (metallurgically) joined.
[0040]
2) Next, an adjustment process is performed on the cylinder body formed in 1) above.
[0041]
In this adjustment step, from the viewpoint of adjusting the hardness of the inner layer 12, it is preferably 1 hour or more, and more preferably 5 to 10 hours, after the cylinder body is heated and reaches 900 ° C., in a temperature range of 900 ° C. to 925 ° C. After the holding, the cylinder body is subjected to an air cooling process, whereby the effect of the inner layer 12 having high wear resistance and the outer layer 13 that complements the inner layer 12 can be obtained more reliably. Thus, a cylinder body having desired characteristics can be obtained by one heating / air cooling process, which is advantageous.
Note that the hardness of the inner layer 12 is preferably 500 HB or more, and more preferably 530 to 690 HB, depending on the time of maintaining the temperature in the temperature range of 900 ° C. to 925 ° C. at this time.
[0042]
3) After the adjusting step, the following mechanical processing steps are performed.
[0043]
In this mechanical treatment step, at least while the inner layer 12 is still in a soft state, the inner peripheral surface thereof is subjected to finish processing such as honing finish and then hardened, and is formed to have a thickness of, for example, 3 mm. In addition, it is good to process so that the surface roughness of the inner peripheral surface of the inner layer 12 may become preferably 20S or less, more preferably 6 to 15S.
For this reason, the piston 17 can be smoothly reciprocated and slid in the slurry pumping cylinder 11, and the wear of the sliding portion (rubber piston packing or the like) of the piston 17 sliding on the inner surface of the slurry pumping cylinder 11 can be reduced. Is advantageous.
In the present embodiment, the outer layer 13 is also machine-finished to have a thickness of 8 mm, and the flange 15 is attached to the outer peripheral side as described above to form the slurry pumping cylinder 11.
[0044]
[Another embodiment]
Hereinafter, other embodiments will be described.
<1> In the above embodiment, the slurry pumping pump provided with two slurry pumping cylinders 11 is exemplified. However, the slurry pumping pump may be provided with one slurry pumping cylinder 11 or may be provided with three slurry pumping cylinders.
Further, the suction part capable of sucking the slurry and the discharge part capable of discharging the slurry, which are provided in the slurry pumping cylinder 11, are not limited to those exemplified in the previous embodiment, and the suction part and the discharge part are separately provided. The suction unit and the discharge unit may be arbitrarily provided so that the suction unit and the discharge unit can be freely switched so that the slurry pumping cylinder 11 can suction and discharge the slurry.
[0045]
<2> The slurry pumping cylinder 11 in which the first layer (inner layer) 12 and the second layer (outer layer) 13 are metallurgically bonded is not limited to the centrifugal casting method illustrated in the above-described embodiment. By a HIP method (hot isostatic pressing method), a metal material of carbon steel or high chromium cast iron may be put in a capsule of a predetermined shape, and may be heated and melt-molded while applying an isostatic pressure by a high-pressure gas, Moreover, you may form by other various metallurgical (metallurgical) joining methods.
Further, the slurry pumping cylinder 11 is not limited to the first layer 12 and the second layer 13 which are metallurgically bonded as described above, but may be a mechanically bonded one by shrink fitting or the like.
[0046]
<3> The slurry pumping cylinder 11 is not limited to the two-layer pipe structure exemplified in the above embodiment, but includes a first layer 12 made of high chromium cast iron on the inner peripheral surface side, and the first layer Any structure having three layers or more may be used as long as the structure has the second layer 12 made of carbon steel on the outside of the steel sheet.
In the present specification, “high chromium cast iron” means a steel having a white iron structure in which chromium carbide (chromium / iron carbide) is dispersed and precipitated on a hard martensite base, and its composition is C: 2.0 to 3.5% by weight, Cr: 12 to 30% by weight, and if necessary, one or two or more elements such as V, Mo, Cu, Ni and the like are added at an arbitrary ratio. .
In the present specification, “carbon steel” means a carbon steel casting according to JIS standards such as SC360, SC410, SC450, SC480, etc., whose composition is C: 0.40 or less, and P: 0.40 Hereinafter, S: 0.04 or less. (Please let me know if the composition is inappropriate.
[0047]
<4> Incidentally, in the slurry pump according to the present invention, as the slurry, for example, various slurries such as concrete, high clay material, mud, mortar, lightweight mortar, lightweight concrete, heavy concrete, scum, etc. can be pumped. Yes, but of course it may be used to pump water.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of a slurry pumping pump according to the present invention; FIG. 2 is a cross-sectional view illustrating an operation state of the slurry pumping pump exemplified in FIG. 1; FIG. Sectional view showing [Description of reference numerals]
A Slurry pump 11 (11a, 11b) Slurry pump cylinder 12 First layer 13 Second layer 14 Suction unit 14 Discharge unit 17 Piston 18 Drive unit 20 Suction-discharge switching unit

Claims (9)

A slurry pumping cylinder for slurry pumping, a piston capable of reciprocating in the slurry pumping cylinder, and a driving device reciprocating the piston in the slurry pumping cylinder,
In the slurry pumping cylinder, a suction unit capable of sucking slurry, and a discharge unit capable of discharging the slurry are formed, and a slurry pump that has the suction unit and the discharge unit switchably provided,
A slurry pump wherein a cylinder body includes a first layer made of high chromium cast iron on an inner peripheral surface side and a second layer made of carbon steel outside the first layer. The slurry pump according to claim 1, wherein the first layer and the second layer are metallurgically bonded. The slurry pump according to claim 1 or 2, wherein the hardness of the first layer is 500 HB or more. The slurry pump according to any one of claims 1 to 3, wherein a surface roughness of an inner peripheral surface of the first layer is 20S or less. It is a manufacturing method of the slurry pumping cylinder of Claim 3, Comprising:
Performing a main body forming step of providing a cylinder main body including the first layer and the second layer;
After subjecting the cylinder body to a heat treatment at 900 ° C. to 925 ° C., an air cooling treatment is performed to perform an adjustment step so that the hardness of the first layer is 500 HB or more.
After the adjusting step, a method for manufacturing a slurry pumping cylinder in which at least an inner peripheral surface of the first layer is subjected to finishing. 6. The method for producing a slurry pumping cylinder according to claim 5, wherein in the adjusting step, a heat treatment is performed at 900C to 925C for 1 hour or more. The method according to claim 5 or 6, wherein the cylinder body is formed by centrifugal casting in the body forming step. 7. The method for manufacturing a slurry pumping cylinder according to claim 5, wherein, in the main body forming step, after the second layer is formed by a centrifugal force casting method, the first layer is formed by fleshy welding. The method according to claim 5, wherein the cylinder body is formed by a HIP method in the body forming step.

Images