JP4680018B2 - High pressure plunger pump - Google Patents

Description

  The present invention relates to a high pressure plunger pump provided with a sealing means for partitioning a high pressure portion and a low pressure portion in a cylinder, for example.

  The high pressure plunger pump directly applies various raw material slurries in the atomization apparatus as shown in FIG. 2, for example, to homogenize the fluid such as the collision of material, atomization by pulverization or emulsification and dispersion of fine particles. It is used for high pressure injection under pressure.

  This high-pressure plunger pump performs high-pressure injection of a raw slurry by a high-pressure plunger 102 that reciprocates in a cylinder 101 as shown in FIG. 3, for example, and is formed between the plunger 102 and the cylinder 101. A sealing device 104 that seals the annular gap 103 and partitions the high-pressure side and the low-pressure side is provided.

  The sealing device 104 includes a rigid top adapter ring 105 from the high pressure side, an elastic ring 106, a packing ring 108 for compressing the elastic ring, and a backup ring 109 having a higher yield strength than the packing ring 108. Thus, the high-pressure plunger pump reliably seals the high-pressure raw material slurry of 245 MPa (for example, see Patent Document 1).

Japanese Patent Laid-Open No. 2002-161982

  However, for the strongly alkaline raw material slurry containing hard particles, such as barium titanate, which is required to have high performance as an electronic component material coupled with the recent increase in demand for ceramic electronic components, In the conventional sealing device as described above, the life of the sealing component is extremely short.

  This is because powders such as barium titanate have high adhesion, and if they are pulverized / dispersed with a pulverizer, they become more likely to adhere to the plunger surface as the particles become monodispersed and atomized. When this adhering powder enters the gap between the plunger and the packing of the sealing device, it not only roughens the plunger surface but also accelerates the wear of the packing, causing the packing to be damaged in a short time and causing the raw material slurry to leak. Because.

  In view of the above problems, an object of the present invention is to provide a high-pressure plunger pump in which the atomized powder of the raw material slurry is less likely to adhere to the plunger surface, and the lifetime of the sealing device can be increased as compared with the prior art. . Another object of the present invention is to provide a high-pressure plunger pump that can maintain a good sealing state with respect to hard particles / strong alkaline raw material slurry.

  In order to achieve the above object, a high-pressure plunger pump according to the first aspect of the present invention is a high-pressure plunger pump that sucks raw material slurry into the cylinder and pressurizes and discharges the raw material slurry by reciprocating sliding of the plunger in the cylinder. A plunger pump comprising: a sealing device that seals an annular gap formed between the cylinder and the plunger to partition the high pressure portion and the low pressure portion; and a powder adhesion preventing means for the plunger, and the sealing The apparatus includes a rigid top adapter ring, an elastic ring, a packing ring for compressing the elastic ring, and a backup ring having a higher yield strength than the packing ring in the annular gap in order from the high-pressure part side. The elastic ring has a substantially U-shaped cross section with a groove portion opened to the high pressure portion side and is in contact with the outer peripheral surface of the plunger. The packing ring includes a cylindrical portion that contacts the plunger outer peripheral surface on the low pressure portion side of the elastic ring, and the cylindrical shape that covers the outer peripheral surface of the elastic ring and presses the elastic ring against the plunger. And a contact surface with the plunger outer peripheral surface of the elastic ring constitutes an adhered powder scraping portion as the powder adhesion preventing means.

  A high-pressure plunger pump according to a second aspect of the present invention is the high-pressure plunger pump according to the first aspect, wherein the elastic ring is made of a urethane elastomer member having a Shore hardness of Hs70 or more and Hs95 or less. is there.

  A high pressure plunger pump according to a third aspect of the present invention is the high pressure plunger pump according to the first or second aspect, wherein the packing ring is formed by filling ultrahigh molecular weight polyethylene with carbon or polytetrafluoroethylene. It is comprised by the member, It is characterized by the above-mentioned.

  A high-pressure plunger pump according to a fourth aspect of the present invention is the high-pressure plunger pump according to any one of the first to third aspects, wherein the powder adhesion preventing means is coated on an outer peripheral surface of the plunger. Including a diamond-like carbon coating layer.

  The high-pressure plunger pump according to the invention described in claim 5 is the high-pressure plunger pump according to claim 4, characterized in that a SiC undercoating layer is provided below the diamond-like carbon coating layer. is there.

  A high-pressure plunger pump according to a sixth aspect of the present invention is the high-pressure plunger pump according to the fourth or fifth aspect, wherein the diamond-like carbon coating layer has a thickness of 1.5 μm or more. Is.

  A high-pressure plunger pump according to the invention described in claim 7 is the high-pressure plunger pump according to claim 4, wherein the diamond-like carbon coating layer is a SiC mixed layer containing SiC. .

  The high-pressure plunger pump according to the invention described in claim 8 is the high-pressure plunger pump according to any one of claims 1 to 7, wherein the powder adhesion preventing means is added to the raw slurry. A dispersant containing a metal-free ashless polycarboxylic acid-based ammonium salt as a main component is included.

  The high-pressure plunger pump according to the invention described in claim 9 is the high-pressure plunger pump according to claim 8, wherein the additive concentration of the dispersant in the raw slurry is 0.5 with respect to the solid weight in the raw slurry. It is characterized by being ˜5 wt%.

  In the high pressure plunger pump of the present invention, the elastic ring of the sealing device that seals the annular gap formed between the cylinder and the plunger to partition the high pressure portion and the low pressure portion includes a groove portion that opens to the high pressure portion side. It has a substantially U-shaped cross section and is made of a cylindrical member in contact with the outer peripheral surface of the plunger, and the contact surface with the outer peripheral surface of the plunger constitutes an adhered powder scraping portion as the powder adhesion preventing means. Therefore, the plunger contact surface of the elastic ring, that is, the lower portion of the substantially U-shaped cross section functions as a powerful scraper with a high contact surface pressure due to the restoring force of the elastic ring and adheres to the plunger outer peripheral surface. Since the finely divided powder is scraped well, it is possible to prevent the adhering powder from entering the gap between the plunger and the packing of the sealing device and causing the wear and damage of the packing. There is an effect that life can be achieved.

  The present invention is a high pressure plunger pump provided with a sealing device for sealing an annular gap formed between a cylinder and a plunger to partition a high pressure portion and a low pressure portion, and a powder adhesion preventing means for the plunger, The elastic ring on the high-pressure part side constituting the sealing device is formed of a cylindrical member in contact with the outer peripheral surface of the plunger with a substantially U-shaped cross section provided with a groove opening to the high-pressure part side. The contact surface constitutes an adhered powder scraping portion as the powder adhesion preventing means.

  Therefore, the elastic ring of the present invention is pressed against the plunger by the packing ring that covers the outer peripheral surface of the ring with the extending portion extending from the low-pressure portion side, and the lower contact portion has a high contact surface pressure due to its restoring force. A certain plunger contact surface functions as a scraper, and scrapes finely atomized powder adhering to the plunger surface, so even for hard and highly adherent atomized powder such as barium titanate on the low pressure part side It is possible to prevent the intrusion into the gap between the plunger and the packing ring, which causes wear and damage to the packing ring, and to extend the life of the sealing device itself.

  Since the scraper function increases as the contact surface pressure increases, the elastic ring preferably has a high elastic modulus. For example, a ring made of a urethane elastomer member having a Shore hardness of Hs70 or more and Hs95 or less is suitable. With a shore hardness smaller than the lower limit of this range, a contact surface pressure sufficient to exert the scraper function of the elastic ring can be obtained, but damage is likely to occur at an early stage because the strength of the ring itself is insufficient. This is because when the Shore hardness is large, the amount of deformation due to pressure is small, and a contact surface pressure sufficient to exhibit the scraper function cannot be obtained.

  Further, by making the packing ring itself a material having a low coefficient of friction as the powder adhesion preventing means, it becomes difficult for the powder to adhere, and the wear resistance is improved and the life can be further extended. Therefore, it is desirable to use an ultra high molecular weight polyethylene material for the packing ring of the present invention.

  Ultra-high molecular weight polyethylene has a molecular weight of 1 million or more and a molecular weight extremely higher than that of general polyethylene. Therefore, it has much higher abrasion resistance, slidability, and impact resistance than general polyethylene. It is also used as a packing ring material in a conventional high pressure plunger pump sealing device. At present, materials having excellent wear resistance and sliding properties have been developed by filling such ultra high molecular weight polyethylene with carbon or polytetrafluoroethylene, and such materials are used in the present invention. It is preferable to use it for the packing ring of the sealing device.

  On the other hand, by making the plunger surface itself have a low friction coefficient as the powder adhesion preventing means, it is possible to reduce the wear of the packing ring and further extend the life of the sealing device. For example, by covering the outer peripheral surface of the plunger with a diamond-like carbon (hereinafter referred to as DLC) coating layer, a powder adhesion preventing effect can be imparted to the plunger surface. The DLC coating layer is nearly twice as hard as the titanium coating layer and has a wear coefficient of about ¼, and since it has an amorphous structure, it has no grain boundaries and can be used as a hard thin film with another polycrystalline structure. Since a much smoother surface can be obtained, it has been used in recent years for surface coating of various jigs and tools that require lubricity, a low coefficient of friction and wear resistance.

  The DLC coating layer may be formed directly on the plunger surface, or may be formed via an underlayer. For example, if a SiC layer resistant to alkali is formed as a base, it is possible to make it difficult to peel the DLC coating layer in an alkaline solution.

  At present, the DLC coating layer is formed by a plasma ion implantation film forming method that can be processed at a relatively low temperature, and a maximum film thickness of about 1.5 μm is generally used in one film formation. Therefore, in order to give sufficient strength and wear resistance to the plunger surface, it is desirable that the DLC coating layer has a film thickness of at least 1.5 μm. The lifetime can be extended.

  Further, instead of forming the DLC coating layer thick, a SiC mixed DLC coating layer containing SiC in the DLC coating layer can also be used. Since this SiC mixed DLC coating layer has a low coefficient of friction, superior wear resistance and long life can be obtained compared to a DLC coating layer having the same thickness.

  This SiC mixed DLC coating layer can be formed, for example, by using the plasma gas as a mixed gas containing SiC gas when the DLC coating layer is formed by the plasma gas.

  In addition to the DLC coating layer, any coating layer having a low coefficient of friction and high hardness can be widely used for covering the outer peripheral surface of the plunger. For example, an ultra-hard thin film BH (Bluish Hard) coating layer is mentioned. This is a new dark blue thin film developed by special plasma synthesis, which has a lower coefficient of friction than the DLC coating layer and a hardness of 20-40% higher.

  With any of the above coating layers of DLC and BH, the friction coefficient of the outer peripheral surface of the plunger and the smoothing of the surface make it difficult for the atomized powder to adhere to the plunger surface and relatively improve the wear resistance of the packing ring. . Furthermore, such a reduction in the coefficient of friction also reduces the friction noise with the packing ring when the plunger slides, thereby reducing the noise of the apparatus.

  Further, as a powder adhesion preventing means, a dispersant for preventing aggregation of the atomized powder and reducing powder adhesion to the plunger may be added to the raw slurry. However, the dispersant is appropriately selected according to the type of atomized powder and the purpose of use.

  For example, when the fine particle raw material is for a high-purity ceramic electronic component, the adhesion to the plunger is reduced without impairing the electrical characteristics of the electronic component. Specifically, a dispersant containing a metal-free ashless polycarboxylic acid ammonium salt as a main component is used. Here, the “main component” refers to a component showing 50% or more of the components constituting the dispersant. It is preferable that the addition concentration of the dispersant in the raw material slurry is 0.5 to 5 wt% by external addition with respect to the weight of the solid content (raw material powder) in the raw material slurry. This is because if the concentration is lower than the lower limit of the range, the effect as a dispersant is insufficient, and if the concentration is higher than the upper limit, there is a concern about influence on electrical characteristics.

  The case where the high-pressure plunger pump according to one embodiment of the present invention is incorporated in the atomization apparatus shown in FIG. 2 to atomize barium titanate particles will be described below. First, as shown in the longitudinal sectional view of FIG. 1, the basic configuration of the high-pressure plunger pump of this embodiment is the same as that of the conventional one. That is, the cylinder 1 is moved by reciprocating sliding of the plunger 2 in the cylinder 1. The raw material slurry is sucked into the inside and the raw material slurry is pressurized and discharged, and the annular gap 3 formed between the cylinder 1 and the plunger 2 is sealed to separate the high pressure portion and the low pressure portion. A device 4 is provided.

  The sealing device 4 includes, in order from the high pressure part side, a rigid top adapter ring 5, an elastic ring 6, a packing ring 8 for compressing the elastic ring, and a backup ring 9 having a higher yield strength than the packing ring 8. Are arranged.

  In this embodiment, the elastic ring 6 is formed of a cylindrical member having a substantially U-shaped cross section with a groove portion 7 opened to the high pressure portion side and in contact with the outer peripheral surface of the plunger 2, and the packing ring 8 is a low pressure of the elastic ring 6. The elastic ring 6 is pressed against the plunger by covering the outer peripheral surface of the elastic ring 6 by the extending portion 8y extending from the cylindrical portion 8x contacting the plunger outer peripheral surface on the part side to the high-pressure part side. The contact surface with the plunger outer peripheral surface, that is, the lower portion of the U-shaped cross section has a function of scraping the adhered powder on the plunger outer peripheral surface in a scraper shape with a high contact surface pressure due to the restoring force of the elastic ring 6. is there.

  In the atomization apparatus in which each elastic ring 6 is composed of a urethane elastomer having a shore hardness of Hs90 and the packing ring 8 is composed of three types of ultrahigh molecular weight polyethylene resins, The collision treatment test for atomizing barium titanate was performed as follows when the DLC coating layer having a thickness of 1.5 μm was provided as the layer 10 via the SiC underlayer and without the coating layer 10. .

  The three types of ultra high molecular weight polyethylene resins are U-PE100 (trade name: manufactured by Nippon Polypenco Co., Ltd.), which has been used as an ultra high molecular weight polyethylene resin, respectively, and fine carbon particles are dispersed based on this. The friction coefficient is obtained by uniformly dispersing polytetrafluoroethylene in U-PE300 (trade name: manufactured by Nippon Polypenco Co., Ltd.) to which wear resistance and antistatic properties are imparted by the above and ultra-high molecular weight polyethylene resin as a base. U-PEASW (trade name: manufactured by Nippon Polypenco Co., Ltd.) greatly reduced.

  In this collision test, as shown in FIG. 2, a raw material slurry is fed into a chamber at 245 MPa and a flow rate of 0.73 kg / min with each high-pressure plunger 2 using a atomizer equipped with a pressure intensifier comprising two high-pressure plunger pumps. The ball (with a diameter of 0.15 mm) collides with the chamber, and after the collision, the slurry is collected and sent to the chamber again to repeat the collision process a plurality of passes.

  Specifically, as a regular pass, barium titanate 6 kg + water 14 kg = 20 kg (30 wt%, pH 12.4) is one lot of raw slurry, and the processing time of one lot 8 passes (20 kg × 8 ÷ 0.73 kg / min) ÷ 60 min =) The processing speed was about 3.5 hours. Further, as an extension pass, after passing a regular pass for 8 passes, 20 passes by a large machine and atomized 20 kg was used as a raw material, and a 18 pass circulation treatment was performed with a treatment time of 8.5 hours. Since this extended path is made from a material that has already been atomized to some extent, it is easy to adhere to the outer peripheral surface of the plunger and to enter the gap between the plunger and the packing ring and to wear the packing ring.

  In the above test, the continuous circulation process is repeated for each sealing device having packing rings of different materials and the presence or absence of the SiC underlayer of the plunger + the coating layer 10 of the DLC coating layer. The life of the sealing device, that is, the packing ring was determined. In this determination, a leak amount of 3 g / min is used as a reference, and a leak amount less than that is not a problem. Table 1 shows the test results of the life determination. In addition, the result of having performed the collision test on the case where the conventional type sealing device as shown in FIG. 3, that is, the case where the elastic ring does not have a scraping structure is incorporated is also shown.

  As is clear from the results in Table 1, the high-pressure plunger pump according to the present example is hard and easy to adhere, and even when the raw material slurry becomes fine alkali barium titanate having a pH of more than 12, the sealing device 4 By adopting a scraping die as a powder adhesion preventing means for the elastic ring 6, the life of the sealing device 4 can be extended compared to the conventional type even in the case of the same material, and the elastic modulus is higher. The life of the sealing device 4 was greatly prolonged by using urethane elastomer.

  Further, the provision of the SiC underlayer and the DLC coating layer 10 on the outer peripheral surface of the plunger 2 as a further powder adhesion preventing means significantly increases the life of the sealing device and makes the packing ring 8 more frictional. It was confirmed that the life of a longer sealing device can be extended by selecting ultra-high molecular weight polyethylene having a low coefficient and excellent slidability. In addition, in the regular pass, when the packing ring 8 is made of U-PEASW, there is no leakage of the raw slurry, and even when it is made of U-PE300, 0.03 to 0.5 g / min after 20 hours. There was only a slight leak.

  This test was terminated when the raw material slurry ran out, but there is also a sealing device that has not substantially reached the end of its life at the end of the test, and in this example, the shape of each member as a powder adhesion preventing means By selecting the most suitable material, even if the raw material slurry is hard particles and strong alkali, it is possible to realize a high pressure plunger pump that can maintain a good sealing state without leakage of the raw material slurry over a longer period of time. It becomes.

  In addition, the above test results examined the case where a SiC underlayer resistant to alkali was formed under the DLC coating layer. Here, the influence on the lifetime of the sealing device due to the presence or absence of the SiC underlayer was examined. did. This is a plunger provided with a DLC coating layer when there is no SiC underlayer and with a conventional sealing device using U-PE100 for the packing ring. The life of the device is determined. The results are shown in Table 2 below.

  As is clear from the results in Table 2, in the extended path where atomization is difficult, the seal as the life of the packing ring in the case of the DLC coating plunger with the SiC underlayer is compared with the case of the DLC coating plunger without the SiC underlayer. The life of the stop device is six times. This is because the DLC coating layer is difficult to peel off from the plunger surface even in the alkaline liquid by passing through the SiC underlayer, which leads to a longer life of the sealing device.

  It should be noted that a longer life can be expected by further improving the wear resistance of the coating layer composed of the SiC underlayer and the DLC coating layer, which has shown a long life as described above. First, it is conceivable to increase the film thickness as an easy method that can extend the life due to wear resistance. Therefore, the same collision test as described above was examined on a layer (double covering layer) in which the DLC coating layer was repeatedly laminated on the SiC underlayer to increase the film thickness twice.

  In this test, the lifetime was determined as the time until the base material (plunger 2 surface) was exposed in a state where it was seen as worn. The life of the DLC coating layer formed only once (single coating layer) was 160 hours, whereas the double coating layer had a life of almost twice as long as 320 hours. The effect of increasing the thickness of the film was confirmed.

  As a method for reducing the friction coefficient of the DLC coating layer itself and improving the wear resistance without increasing the film thickness of the DLC coating layer, there is a method of forming a SiC mixed DLC coating layer containing SiC in the DLC coating layer. is there. The SiC content is 1% or more, preferably 5% or more and 70% or less in terms of weight. In such a mixed layer, inclusion of SiC makes it more difficult to separate from the plunger surface than a coating layer made of only a normal DLC coating layer, and also reduces the friction coefficient. This mixed layer can be formed by mixing SiC gas with the plasma gas used when forming the DLC coating layer.

  For example, in the mixed layer having a SiC content of 10% to 50%, the friction coefficient of the plunger surface without the coating layer was about 0.2, and the friction coefficient of the normal DLC coating layer was about 0.15. On the other hand, the coefficient of friction was greatly reduced to 0.08.

  In addition, when the lifetime was determined by exposing the plunger surface in the same manner as described above, the lifetime of the SiC mixed layer (single coating layer) reached 480 hours, which was significantly larger than that of a normal DLC coating layer. It was confirmed that the service life was prolonged. In this mixed layer, the low friction coefficient and wear resistance of the original DLC coating layer are further improved, and the wear resistance of the raw material powder is prevented due to the effect of improving the wear resistance. As a result, the lifetime of the sealing device can be further prolonged.

  Moreover, as a plunger coating layer whose coefficient of friction is lower than that of the DLC coating layer, in addition to the SiC-mixed DLC coating layer as described above, an ultra-hard thin film BH coating layer can be mentioned. This BH coating layer has a lower coefficient of friction and a higher hardness than the DLC coating layer, and when used as a plunger coating layer, it provides a longer lifetime for the sealing device than a coating layer consisting only of the DLC coating layer. Can be expected.

  As a further powder adhesion preventing means, a dispersant for preventing the powder particles from aggregating and easily adhering to the plunger surface may be added to the raw material slurry. Below, a collision atomization test is performed when a dispersant mainly containing an ashless polycarboxylic acid-based ammonium salt containing no metal is added at various concentrations as a dispersant that does not impair the electrical characteristics of the electronic product. The comparison was made in comparison with the case where no dispersant was added.

  In this test, the barium titanate fine particles are formed in the normal pass under the same conditions as in the above-described collision test when the packing ring 8 is made of U-PE100 and the plunger 2 has no coating layer in the atomization apparatus shown in FIG. Collision processing was carried out to make it easier, and the life of the sealing device was similarly determined. The results are shown in Table 3 below.

  As shown in Table 3, it was confirmed that the effect of extending the life of the sealing device can be obtained by adding a dispersant. Moreover, the suitable density | concentration with which the addition effect of a dispersing agent is exhibited was 0.5-5 wt%. Therefore, it is possible to further extend the life of the sealing device by appropriately adding such a dispersant together with the above-described plunger coating layer, a low frictional resistance member of the packing ring, and the like.

  As shown in the above embodiments, in the high-pressure plunger pump according to the present invention, the elastic ring has a scraping-type configuration, and by appropriately selecting the design conditions including the above members, the raw material Not only does the slurry contain hard particles, but even when it is strongly alkaline, it can maintain a sufficient sealing state, and good atomization treatment can be performed even for raw material slurry that has been difficult in conventional atomization equipment. It can be done efficiently.

It is a schematic longitudinal cross-sectional view which shows the structure of the high pressure plunger pump by one Example of this invention. It is a whole lineblock diagram showing an example of an atomization device. (A) is a schematic sectional drawing which shows the structure of the conventional high pressure plunger pump, (b) is an enlarged view of the sealing device part enclosed with the dotted line of (a).

Explanation of symbols

1, 101: cylinder 2, 102: plunger 3, 103: annular gap 4, 104: sealing device 5, 105: top adapter ring 6, 106: elastic ring 7: groove portion 8, 108: packing ring 8x: cylindrical portion 8y: Extension portion 9, 109: Backup ring 10: Plunger coating layer (SiC underlayer + DLC coating layer)

Claims (9)

In the high-pressure plunger pump that sucks the raw material slurry into the cylinder by reciprocating sliding of the plunger in the cylinder and pressurizes and discharges the raw material slurry,
A sealing device for sealing an annular gap formed between the cylinder and the plunger and partitioning the high-pressure part and the low-pressure part, and means for preventing powder adhesion to the plunger,
The sealing device includes a rigid top adapter ring, an elastic ring, a packing ring for compressing the elastic ring, and a backup ring having a higher yield strength than the packing ring in order from the high-pressure part side in the annular gap. Are arranged,
The elastic ring is formed of a cylindrical member in contact with the outer peripheral surface of the plunger with a substantially U-shaped cross section provided with a groove portion opened to the high pressure portion side,
The packing ring extends from the cylindrical portion that contacts the outer peripheral surface of the plunger on the low pressure portion side of the elastic ring and the cylindrical portion that covers the outer peripheral surface of the elastic ring and presses the elastic ring against the plunger toward the high pressure portion side. An extending portion,
A contact surface of the elastic ring with the plunger outer peripheral surface constitutes an adhering powder scraping portion as the powder adhering prevention means.   The high-pressure plunger pump according to claim 1, wherein the elastic ring is made of a urethane elastomer member having a Shore hardness of Hs70 or more and Hs95 or less.   The high-pressure plunger pump according to claim 1 or 2, wherein the packing ring is formed of a member obtained by filling ultra high molecular weight polyethylene with carbon or polytetrafluoroethylene.   The high-pressure plunger pump according to any one of claims 1 to 3, wherein the powder adhesion preventing means includes a diamond-like carbon coating layer coated on an outer peripheral surface of the plunger.   The high pressure plunger pump according to claim 4, wherein a SiC undercoating layer is provided under the diamond-like carbon coating layer.   The high-pressure plunger pump according to claim 4 or 5, wherein the diamond-like carbon coating layer has a thickness of 1.5 µm or more.   The high-pressure plunger pump according to claim 4, wherein the diamond-like carbon coating layer is a SiC mixed layer containing SiC.   The powder adhesion preventing means includes a dispersant added to the raw material slurry, the main component being an ashless polycarboxylic acid-based ammonium salt that does not contain metal. The high-pressure plunger pump according to any one of the above. The high-pressure plunger pump according to claim 8, wherein the additive concentration of the dispersant in the raw slurry is 0.5 to 5 wt% with respect to the solid content weight in the raw slurry.

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