JP2788186B2 - End cover structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic centrifugal pump having excellent corrosion resistance, wear resistance, penetration resistance and heat resistance.
The present invention relates to an end cover structure used for sealing an end face of a rotating device such as a roots pump, a liquid ring pump, a screw pump, or for sealing an end face of a rotating portion of a ceramic valve.

[0002]

2. Description of the Related Art An end cover structure of a rotary device used for the above purpose is disclosed in Japanese Utility Model Laid-Open No. 2-24092.
As shown in the publication, in order to seal the rear side of the impeller at the opening end face of the spiral chamber in which the impeller of the casing is stored, the liquid contact part is made of a disc-shaped ceramic, and the outside thereof is made of metal. The one protected by a member is known. FIGS. 8 and 9 show such an end cover structure having a conventional structure, in which a cylindrical boss portion 3 is integrated with a center portion of a ceramic end cover 1 via a round portion 2. The end cover 1 is provided at the center of the metal armor 4 provided outside the armor 4.
An outer joint portion 5 having a curved shape corresponding to the outer surface extending from the boss portion 3 to the round portion 2 is formed, and the joint portion 5 is bonded to the boss portion 3 and the round portion 2 with an adhesive layer 6. The configuration is as follows.

In such a conventional end cover structure, the end cover 1 and the armor 4 are adhered by an adhesive, but a shaft sealing member for sealing the end cover 1 and the shaft is provided on the inner diameter side of the end cover 1. Is mounted on the end face of the boss 3 of the end cover 1.
The fixed ring 8 is held by the clamp ring 9 via the through hole, and the fixed ring 8 is further pressed against the end face of the boss 3 of the end cover 1 by tightening the bolt 10. in this case,
A load is applied to the joint 5 of the armor 4 in the direction of moving rightward in the figure with the outer diameter 11 of the armor 4 as a fulcrum, while the outer diameter 12 of the end cover 1 is applied to the boss 3 of the end cover 1.
As a result, the adhesive layer 6 moves in the left direction in the figure, so that an axial shearing force is generated in the adhesive layer 6, and as a result, a tensile stress is generated in the round portion 2 of the end cover 1.

When high-temperature liquid is introduced into the pump,
While the end cover 1 is rapidly heated and the entire body expands in diameter due to thermal expansion, the temperature of the bonded armor 4 is gradually increased by heat transfer from the end cover 1. The armor 4 is further shrink-fitted, and the tensile stress generated near the round portion 2 of the end cover 1 increases.

Further, when the pressure of the pump is high, the end cover 1 is displaced rightward in the drawing with the outer diameter portion 12 of the end cover 1 as a fulcrum, and a tensile stress is generated in the round portion 2 of the end cover 1. I do.

On the other hand, when the pump is used to transfer a high-temperature liquid, it is necessary to bond the bonding portion with a high-temperature curing adhesive in order to increase the high-temperature bonding strength of the bonding portion. In this case, as the adhesive product having the adhesive layer 6 cured at a high temperature is cooled to room temperature, the inner circumference of the armor 4 has a shrink fitting configuration in which the outer diameter of the boss 3 of the end cover 1 is compressed. This is because the metal armor 4 has a larger thermal expansion coefficient than the ceramic end cover 1. At this time, a tensile stress is generated at the round portion 2 at the boundary between the disk portion of the end cover 1 and the boss portion 3 where no shrink fitting force acts.

As described above, when the pump is used under severer operating conditions or a high-temperature liquid, an excessive tensile stress acts on the round portion 2 of the end cover 1 made of ceramics in a complex manner. There was a problem that the breakage of the device occurred. In order to avoid such a problem, the axial length of the boss portion 3 of the end cover 1 is extended, and the end cover 1 is bonded to the metal armor 4 avoiding the round portion 2 or the open end of the boss portion 3. Although it is possible to do so, it leads to an increase in the dimensions of parts, which is not preferable. On the other hand, it is possible to improve the safety factor against the generated stress by using high-strength ceramics, but high-strength ceramics are generally expensive and impractical.

[0008]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and does not greatly increase the size of the end cover, and does not use expensive high-strength ceramics. It is an object of the present invention to provide a ceramic end cover structure capable of tightening, introducing a high-temperature and high-pressure liquid into a pump, and using a high-temperature curing adhesive having high adhesive strength.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to an end cover having a shape in which a cylindrical portion is connected to the center of a perforated disk. In the bonded end cover structure, a circumferential groove and an elastic layer in contact with the groove are provided in the inner diameter of the metal member, and an adhesive is formed in a gap formed between the elastic layer and the outer diameter of the end cover. And the adhesive is fixed to the outer diameter of the end cover, and the outer diameter of the adhesive layer is larger than the inner diameter of the metal member.

The metal member is composed of a cylindrical portion corresponding to the cylindrical portion of the end cover and a disk portion, and the cylindrical portion and the disk portion are engaged by a screw or a bayonet mechanism. It is preferable to adopt a structure in which the gap between the joining portions is elastically supported. Further, the elastic layer and the elastic support of the engaging portion between the cylindrical portion and the disk portion of the metal member are made of silicon rubber, butadiene rubber, chloroprene rubber, nitrile rubber, foamed fluororesin, or epoxy resin containing 5 equivalents or more of thiochol. It is preferred to consist of either. Further, it is preferable that the adhesive is made of any one of a thermosetting epoxy resin, an acrylic resin, and a urethane resin.

[0011]

In the end cover structure of the present invention thus constituted, the end cover and the metal member (armor) are joined by an adhesive, and a fixed ring as a shaft sealing part is attached to the end face of the end cover. When pressure bonding is performed by a clamp ring via a gasket, an axial thrust force is generated at the bonding portion, but no excessive tensile stress is generated at the round portion of the end cover. In addition, when a high-temperature liquid is introduced into the pump, the ceramic liquid-contacting part of the end cover is rapidly heated and the dimensions are enlarged, whereas the bonded metal part is gradually heated, so that the ceramic cylindrical part is further baked. Although it is in the state of being fitted, the present invention can suppress the tensile stress generated near the round portion of the end cover.

Further, when the pressure of the pump is high, even if the end cover is displaced about the outer peripheral corner portion as a fulcrum, the tensile stress generated near the round portion of the end cover can be suppressed. When the pump is used to transfer a high-temperature liquid, it is necessary to bond with a high-temperature curing type adhesive in order to increase the strength of the bonding portion, but the bonded product having the bonding layer cured at high temperature is cooled to room temperature. Accordingly, the tensile stress can be suppressed even when the inner periphery of the metal portion has a so-called shrink-fit configuration in which the outer periphery of the ceramic portion is compressed. Thus, even when used under severer operating conditions or used in high-temperature liquids, the tensile stress generated near the round part of the end cover is relaxed, and the dimensions of the parts are enlarged to avoid such defects, There is no need to use expensive high-strength ceramics.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to the illustrated embodiments. FIG. 1 is a central longitudinal sectional view of the end cover structure of the embodiment. In the drawing, reference numeral 1 denotes an end cover made of ceramics, which has a shape in which a boss 3 which is a cylindrical portion is connected to the center of a disk. A circumferential groove 13 is formed in the inner diameter of the armor 4 as a metal member, and silicon rubber, butadiene rubber, chloroprene rubber, nitrile rubber, foamed fluororesin, and epoxy resin containing at least 5 equivalents of thiocol are formed on the inner surface thereof. Elastic layer selected from any of
14 are provided. The elastic layer 14 is applied to the inner diameter of the armor 4 according to the respective hardening specifications after spraying, brush-painting or fluid-immersing an emulsion of the above-mentioned kind of elastic body with a solvent or the like. Further, a sheet made of the elastic body may be bonded to the inner diameter of the armor 4. At this time, the inner diameter of the armor 4 is preferably roughened by sandblasting or the like in order to firmly adhere the elastic body. Further, after the axial end face of the outer diameter side of the end cover 1 and the axial end face of the armor 4 are press-fitted with the cushioning material 15 interposed therebetween, the boss portion 3 of the end cover 1 and the armor 4
A resin selected from an epoxy resin, a urethane resin, or the like is injected into the gap, and joined.

The function of the elastic layer 14 will now be described. When a material having a coefficient of thermal expansion of the armor 4 larger than that of the end cover 1 is selected, the adhesive layer 6 is made of, for example, epoxy-based material.
Since the armor 4 is heated and hardened to 0 ° C. or more at the curing processing temperature, the diameter of the armor 4 is larger than that of the end cover 1. It is larger than the gap. For this reason, after the resin is injected and the resin is cured at the curing treatment temperature, the end cover 1 and the armor 4 are cooled to room temperature.
Acts on the outer diameter of the boss portion 3 of the boss. For this reason, a tensile stress acts on the round portion 2 of the end cover 1, and when other use conditions are added, the tensile stress increases remarkably, and the ceramic end cover 1 is damaged. On the other hand, in the present invention, the shrink-fitting force is reduced by the elastic layer 14 contracting by the amount corresponding to the reduction of the adhesive layer gap, and the tensile stress acting on the round portion 2 of the end cover 1 can be reduced. As a result, the end cover structure of the present invention can be used safely without expansion of the tensile stress even when conditions such as temperature, pressure, and uneven tightening of the shaft seal portion in the use state are added synergistically. Can be.

The O-ring 16 shown in FIG. 1 prevents the resin from leaking to a portion other than the necessary bonding portion when an epoxy resin, a urethane resin, or the like is injected into a gap between the boss 3 of the end cover 1 and the armor 4. In addition, it is preferable to install the adhesive layer 6 so that the resin is filled without bubbles or voids. Further, the tensile stress acts on the round portion 2 of the end cover 1 as described above, and stress concentration is likely to occur at the boundary between the bonded portion and the non-bonded portion. Since the tensile stress acts due to the difference in the thermal expansion coefficient, the adhesive layer 6 is formed not only on the outer periphery of the boss portion 3 of the end cover 1 but also on the outer diameter side of the round portion 2 and the disk portion connected to the boss portion 3. It is preferable to extend to the end face. Also, a sealing material 17 made of a silicone sealant or the like is provided on the outer diameter crimping surfaces of the end cover 1 and the armor 4 so that the buffer material 15 does not corrode due to the atmosphere and liquid does not penetrate into the inner diameter of the end cover 1 and the armor 4. It has been applied.

FIG. 2 is a sectional view showing an embodiment of the present invention in more detail, wherein at least one of the grooves has a depth of 15-70.
% Elastic layer 14 is provided. The reason for this is that the elastic layer
When 14 is set to 70% or more, the shrink fitting stress reduction effect increases, but the relative displacement between the end cover 1 and the armor 4 occurs, and when it is 15% or less, the shrink fitting stress reduction effect becomes small. . The groove may be continuous like a screw or independent like an O-ring groove. The outer diameter of the adhesive layer 6 must be larger than the inner diameter of the armor 4, that is, ensure the * dimension in FIG. is required. The reason is that when the shaft sealing part is attached to the boss portion 3 of the end cover 1, the end cover 1 and the armor 4 are not separated from each other due to the axial shearing force acting on the adhesive layer 6 as described above. It is.

In order to reduce shrinkage stress due to a dimensional difference between the end cover 1 and the armor 4 at the time of bonding and curing,
The adhesive layer 6 may be provided on the end cover 1 or on both the end cover 1 and the armor 4. However, since the portion where the elastic layer 14 is provided reliably controls the elastic effect, It must be a machined circumferential groove. FIG. 3 is a cross-sectional view showing another embodiment, in which the circumferential groove 18 provided on the outer diameter of the boss 3 of the end cover 1 has a shape having no edge in the cross section to reduce stress concentration. Further, as shown in FIG. 3, the inner diameter of the armor 4 may form an anchor for fixing the adhesive layer 6 by sandblasting, chemical treatment, or the like, and further the adhesive layer 6 is completely filled with resin without bubbles. And to have multiple resin inlets
It is preferable to provide 23 so that it can be confirmed that the injected resin is discharged from the right end face of the adhesive layer 6 in FIG.

FIG. 4 is a sectional view showing a further preferred embodiment. Normally, when attaching the shaft sealing part to the boss portion 3 of the end cover 1, the fixed ring 8 is determined by the difference between the diameter of the contact surface of the fixed ring 8 and the pitch diameter of the screw for fixing the fixed ring 8 (* in FIG. 4).
Is tightened, a bending moment indicated by an arrow acts on the boss 3 of the end cover 1. When a large tightening force is required or when uneven tightening is performed, the bending stress increases the tensile stress generated in the round portion 2 and may damage the end cover 1. In order to prevent this, in the embodiment of FIG. 4, the inner diameter side of the armor 4 is divided into a cylindrical portion 19, and this cylindrical portion 19 is first joined to the end cover 1 and then mechanically connected to the armor 4. . When the cylindrical portion 19 is thinner, shrink-fit stress can be reduced by plastic deformation due to shrink-fitting force, and a ceramic having high strength and elasticity such as partially stabilized zirconia may be used. Further, for the reason described in (paragraph 0015), it is preferable that the cross section of the cylindrical portion 19 is L-shaped.

The connection between the armor 4 and the cylindrical portion 19 is preferably a screw connection or a bayonet connection. FIG. 5 shows a central longitudinal sectional view of the end cover structure in the case of the bayonet connection. As shown in FIGS. 6 and 7, the cylindrical portion 19 and the corresponding armor 4 in the bayonet portion 22 are each constituted by a plurality of engaging portions divided in the circumferential direction.

The joint between the armor 4 and the cylindrical portion 19 is preferably provided with a gap of 0.02 to 0.5 mm in order to further reduce the bending moment generated in the boss 3 of the end cover 1. Silicon rubber, butadiene rubber, chloroprene rubber, and nitrile are used to prevent axial and radial displacement between the cylindrical portion 19 and the armor 4 and to prevent corrosion of the end cover 1 and the inside of the armor 4 due to the atmosphere. It is preferable to fill an elastic resin such as rubber, foamed fluororesin, or epoxy resin containing 5 equivalents or more of thiochol. When a fitting portion is provided at the engagement portion between the cylindrical portion 19 and the armor 4, the inner diameter of the armor 4 is reduced by displacing the armor 4 in the axial direction with the outer diameter portion of the armor 4 as a fulcrum. In order to prevent the cylindrical portion 19 from being compressed from the outer diameter to the inner diameter from the outer diameter of the fitting portion, it is preferable to add a radius as shown in FIG. In addition, it is desirable that the end cover 1 and the armor 4 are integrated at the outer diameter portion in order to facilitate assembly and adjustment when connecting the end cover structure to another component. For this purpose, it is preferable to extend the armor 4 in the axial direction so as to fit the outer diameter of the armor 4 with the outer diameter of the end cover 1, and to fix the armor 4 with a snap ring 21.

In order to confirm the effects of the present invention described above, an end cover structure having a conventional structure employing an epoxy resin which is cured at 150 ° C., and an end cover structure having an elastic layer of 0.2 mm butadiene rubber. And an end cover structure in which armor is divided. After attaching them to the pump as shown in FIG. 8 and further attaching the fixing ring to the end cover with a tightening bolt with a torque of 20 N-m, a high-temperature liquid of 0.5 MPa was introduced into the pump, The cover was checked for damage. As a result, the end cover structure of the conventional structure was damaged when a liquid having a temperature difference of 120 ° C. was introduced,
Temperature difference 160 ° C
No damage was observed even when the liquid was introduced, and the end cover structure obtained by dividing the armor was not damaged even when the pressure was further increased to 1 MPa.

[0022]

As described above, the end cover structure of the present invention can suppress the tensile stress generated in the vicinity of the round portion of the end cover, and can increase the size of parts and increase the cost of high cost. Without using high-strength ceramics
It can withstand harsh use conditions. Although the above description has been made mainly on the embodiment of the end cover for sealing one end of the spiral chamber of the pump casing, the present invention is also applied to an end cover structure for sealing a rotating shaft portion of ceramic valves and the like. be able to.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view showing a second embodiment of the present invention.

FIG. 3 is a sectional view showing a third embodiment of the present invention.

FIG. 4 is a sectional view showing a fourth embodiment of the present invention.

FIG. 5 is a sectional view showing a fifth embodiment of the present invention.

FIG. 6 is a front view showing a fitting according to a fifth embodiment.

FIG. 7 is a front view showing a fitting according to a fifth embodiment.

FIG. 8 is a sectional view showing a main part of a conventional example.

FIG. 9 is a partial sectional view showing a conventional example.

[Explanation of symbols]

1 end cover, 2 ares, 3 boss, 4 armor, 5 joints, 6 adhesive layer, 7 gasket, 8
Fixing ring, 9 clamp ring, 10 bolt, 11 armor outer diameter, 12 end cover outer diameter, 13 groove, 14
Elastic layer, 15 cushioning material, 16 O-ring, 17 sealing material, 18
Circumferential groove, 19 cylindrical part, 20 ares, 21 snap ring, 22 bayonet part, 23 resin inlet

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F04D 7/06 F04D 29/42

Claims (5)

(57) [Claims] 1. An end cover structure in which a metal member is bonded to the outer diameter of a cylindrical portion of a ceramic end cover in which a cylindrical portion is connected to the center of a perforated disk. A circumferential groove and an elastic layer in contact with the groove are provided, and a gap formed between the elastic layer and the outer diameter of the end cover is filled with an adhesive to fix the adhesive to the outer diameter of the end cover. And an outer diameter of the adhesive layer is larger than an inner diameter of the metal member. 2. A metal member comprising two members, a cylindrical portion corresponding to a cylindrical portion of an end cover and a disk portion, wherein said cylindrical portion and said disk portion are engaged by a screw or a bayonet. The end cover structure according to claim 1, wherein the gap between the portions is elastically supported. 3. The elastic layer and the elastic support of the engaging portion between the cylindrical portion and the disk portion of the metal member are made of silicon rubber, butadiene rubber, chloroprene rubber, nitrile rubber, foamed fluororesin,
The end cover structure according to claim 1, comprising an epoxy resin containing 5 equivalents or more of thiochol. 4. The end cover structure according to claim 1, wherein the adhesive is made of one of a thermosetting epoxy resin, an acrylic resin, and a urethane resin. 5. The end cover structure according to claim 1, wherein the end cover structure is used for an end cover for sealing one end of a spiral chamber of a casing of a turbomachine.