DE1596972A1 - Wear-resistant items and covers for them, as well as processes for manufacturing the covers - Google Patents

Description

Ritter Pfaudier Corporation
Rochester J>, New York.

"Wear-resistant articles and coatings therefor, and methods of making the coatings.

The invention relates to wear-resistant articles and coatings therefor and to a method for the production of said coating and in particular on surfaces that are suitable for use suitable as sealing surfaces in mechanical seals.

In industries where large amounts of media are processed in containers or moved by pumps, it is It is common to create devices that have rotating waves that extend into medium-entnaltende vessels

• al «

00561Ö / ÜÖ64

extend. It is often necessary to open the openings to seal, through which the rotating waves penetrate into the vessels in order to prevent the leakage of media, To prevent vapors or lubricants. Stuffing boxes or mechanical seals are largely used for this purpose.

Mechanical seals are becoming more and more the preferred device for such uses have been adopted because they represent a more effective seal and do not require frequent adjustments Mechanical seals, however, include parts that are constantly exposed to sliding friction and eventually wear out to the extent that replacement becomes necessary. The repair or the Replacing the seals is costly and time consuming and often requires the whole thing to be shut down Process · It is therefore desirable to keep the service life within the components of the mechanical To increase sealing

A mechanical seal, as described in detail below, consists of one rotating part, a stationary part, a facility under Pederdruok and one static sealing device that prevents leakage

009819/0964

between the shaft and the rotating seal ring, which are stationary with respect to each other, should prevent. The rotating part and the stationary part have highly machined upper · » surfaces that lie against each other and are held in contact by the force exerted by the Spring preload device is applied.

A commonly used embodiment of a mechanical seal used a stationary seal seat capable of a corrosion resistance "alloy or a ceramic material is produced and a circumferential seal head, the relatively soft from a non-corrosive material is prepared, such as graphite and polytetrafluoroethylene _e The mutually Matching surfaces of the rotating and stationary parts are generally selected from mutually compatible materials to ensure low friction, long life and corrosion. To achieve resilience.

When choosing materials for use in the mating parts of the seals ceramic materials were quite popular because of their excellent resistance properties « ability to resist wear and tear and corrosion. the

" ⁵ " 009819/0964

Brittleness and the general sensitivity of ceramic materials to thermal shock however, they are significant limitations. Historically, ceramic sealing rings have become numerous broken during manufacture and assembly and others fail in operation if the shaft to be sealed hits the ring. The thermal shock properties are poor because of the inherently low thermal conductivity of ceramic materials.

Ceramic coatings on metal layers have been suggested as the ideal solution to the above problems, because the ceramic part is resistant to corrosion Wear and tear available and the metal «

and underlayer the ease of manufacture / better thermal conductivity. Ceramic coatings, which can be applied by welding rods or spray electrodes, however, do not have generally accepted because homogeneous and reliable coatings are not easy to achieve and there are often high wear rates of the matching parts. Also included Such ceramic parts connecting pores, which have a direct passage from the surface to Result under layer and therefore the metal pads

~ 4 ~ 0 0 3 819/0964

do not protect against corrosive media,

Glass coatings on a metal base can be an advantageous material · Although the glass in and of itself and on its own is relatively brittle and a poor conductor of heat, if If a thin layer is applied to a metal base, the properties of the composite object essentially those of the metal base-glass coatings can be divided into simply by means of known painting techniques apply and constitute standard materials for use in resisting corrosion. Though homogeneous glass is generally less resistant to tensile stress than solid ceramic material, After a glass coating has chipped off, the metal underlayer remains in the position * partially the puncture The entire part continues to take over · In contrast, the failure is a solid ceramic coating is often a catastrophic event that causes immediate leakage of the Medium can be done that is to be sealed. It is clear in this way that covered with glass Metals have inherent advantages that make them suitable for use in mechanical waterproofing Let it be obvious · However, were using

0ÜS819 / 0Ö6A

Glass-coated metals have not yet been used because despite their excellent corrosion resistance « ability and the utmost reduction in physical disadvantages through the use of a Metal underside does not provide sufficient glass surfaces Wear resistance have shown their use in industrial applications to be justified.

It is therefore a primary object of the invention to provide types of wear-resistant glass which suitable for use as enamel coatings

Recently, new partially crystallized glass-ceramic coating materials have been developed which show improved physical and mechanical properties, such as resistance to heat hook and impact, corrosion resistance, thermal conductivity and thermal stability at higher working temperatures than conventional enamelling materials.These properties show that such materials are well suited for use as coatings to seal seats and heads in mechanical seals.However, attempts by the inventors to use partially crystallized oils as enamel for earring rings were unsuccessful because the rings failed at relative speeds greater than 4 , 50 m a second, this one

009819/0964

Failure occurred because of the excessive heat resulting from the frictional forces exerted by the Sliding contact between the sealing surface and the sealing seat.

Accordingly, it is a further object of the present invention to provide a sealing cover material made from a partially crystallized glass that has improved wear and tear has properties and is able to reduce frictional heat to a minimum, which occurs at high temperatures Speeds is developed.

It has been shown that if a relatively soft surface, such as graphite in sliding « touching a hard surface, such as ceramic material, is a reduction in friction achieved by the lubricating effect of particles rubbed off by the softer surface. This lubricating effect happens where the part « Some of the softer surface is deposited on the harder surface and so the area Reduce direct contact between the softer and the harder surface. With that, however this deposit can fix on the harder surface, must have this roughness on which the softer particles can anchor themselves. at

~ ^Ί ~ 00981 9/098 A

A primary requirement of a sealing surface is the relative softness and smoothness of the surface. In order to achieve the required surface properties, the adjacent surfaces usually with high precision on up to three light band smoothing and four micro-inch PlMS roughness lapped.

The invention has set itself the goal of creating a surface that has sufficient flatness and smoothness is characterized to act as a sealing surface but still has voids on it Surface has to facilitate the anchoring of particles that erode out of a softer surface are.

In mechanical seals, the abutting surfaces are usually held in contact with one another by pretensioning. In such cases, the loss of surface caused by wear is compensated for by the pressure of the springs, so that a self-adjusting effect is achieved. If the surface of the sealing surface is treated in such a way that it provides the desired voids, what is gradually destroyed will eventually be destroyed

-8th-

009819/0964

Wear of the surface the effect of the surface treatment · At this point the rate of wear increases sharply, thus accelerating the time to replace the seal · It is therefore desirable and a further aim of the invention to have a glass or glass » to provide ceramic body is such that the surface has continuous roughness, despite gradually wear taking place of the body itself ₀

In creating a sealing surface that is constant has a surface with roughness, it really is that the structural changes, the outstanding properties the wear resistance and corrosion resistance are not adversely affected. rivers characteristic of the basic materials. So it is necessary to get the roughness mentioned above to be achieved without creating continuous channels from the surface to the base it is of the utmost importance not to increase the sensitivity to heat socks. It is therefore a An important point of the invention to provide a method for the surface roughness mentioned without adversely affecting the inherent properties of the base material.

It has been found that the advantages of the invention are achieved by adding materials to it a basic glass recipe that changes during the firing process

009819/0964

ΛΟ

volatilize to form a multitude of individual but unrelated bubbles or cavities « create space within the end product. The term "volatilize" as used herein should designed to include the formation and entrapment of gases within the glass mass

Furthermore, it has been found that an excellent plated metal with glass unit can be provided by forming a plurality of individual bubbles or cavities within a semi-crystalline glass coating ₀

Further features and advantages of the invention emerge from the following description of an exemplary embodiment shown in the attached schematic drawings.

Fig. 1 is a side view, partially in section, of a media agitator having a mechanical one. Seal,

Pig. Figure 2 is a graphic representation, enlarged approximately 100 times, of a micrograph of a crystallized glass made according to the invention *

"10-

009819/0964

In Flg. 1 shows a vessel 2 with an agitator shaft, which is driven by a motor (not shown) or Another drive device is driven, which is provided through an opening provided with a splash The shaft 4 ends in an impeller (not shown) or another one that extends into the vessel 2 Mixing device.

A mechanical seal which is shown generally at, surrounding the agitator shaft 4 and includes a stationary seal seat 14, a circumferential seal head 16 and a spring group I8 _e The order "running seal head 16 has a highly top" surface-treated surface, the finely in a similar The machined surface of the stationary sealing seat 14 strikes the sealing seat 14 has a glass or glass ceramic coating 15 A spring holding part 1 is attached to the rotating shaft by means of adjusting screws Π The stationary sealing seat 14 is clamped in its position by a sealing housing and holds the spring group 18 by pretensioning the sealing head 16 into contact with the sealing seat 14. A static sealing device 22 (O-ring or a wedged Teflon part) is provided in order to create a seal between the shaft 4 and the sealing head which is essentially in relation to one another are static «,

009819/0964

In operation, the seal between the circulating head 16 and the stationary seat 14 by the intimate Contact between the highly polished surfaces of these components caused by the Spring tension of the spring group 1 $.

The present invention particularly aims to create a glass or glass ceramic material that is suitable for use as a coating material in the construction described above.

Fig. 2 shows a glass mass with a plurality of non-communicating cavities or Interruptions, some of which cut the surface «

The following specific examples illustrate the manner in which the benefits of the present Invention can be achieved.

009819/0964

Has: 1596972 EXAMPLE I. 57.5 8.8 the following 9.7 A glass frit was made 6.9 Oxide addition 9.4 SiO ₂ 2.8 TiO ₂ 5.1 Al ₂ O ₅ Na ₂ O Li ₂ O SrO Fe ₂ O ₅

100 parts of the frit were ground with the following components:

4.0 parts of carbon-containing silicate (99 # SiO ₂ ), 0.4 parts of bentonite, 4.0 parts of enamelled clay, 0.62 part of potassium chloride, 0.21 part of sodium nitrate

5.0 parts silica 45.0 parts water _β

The above mixture was sprayed onto a mild steel backing · *, baked at 882 ⁰ C and then heat-treated for 1 1/2 hours at 782 ⁰ C.

The resulting product was cut to reveal a partially crystallized glass with a plurality more at random, not with each other

009819/0964

_i -x.

communicating cavities or voids as graphically represented in Pig * 2.

EXAMPLE II «

100 parts of the same frit as used in Example I. was produced, was ground with the following ingredients:

20 parts SiO ₂ 8 parts enameled _{clay 4 parts 25} 0.4 parts borax 0.5 parts MgCO, 0.25 parts NaNO ₂ 1.5 parts LiP 61 parts H ₂ O

Above mixture was sprayed onto a metal substrate, baked at 882 ⁰ C and treated 1 1/2 hours at 782 ⁰ C with heat ·

The product was cut open and photomicrograph of the product obtained showed a product that was similar to that of example I

-14-

009819/0964

EXAMPLE III.

The glass composition according to Example I was based on introduced the surface of a sealing ring within a mechanical seal according to the invention. A glass composition the same in all respects except for the lack of volatility Components, was applied to another sealing ring. The ring coated according to the invention still worked satisfactorily after 6 months of continuous use. The ring made according to standard techniques was established, failed after just 4 hours.

Although the article of the invention has been described in terms of its usefulness as a sealing surface, it is not so limited and is useful in many other applications where wear resistance is required. For example, in the textile industry, where fibers run at high speeds over various parts, a glass composition with an organic flaking agent added in accordance with the invention increased the useful life of a part from 3 days to 5 days Months, and in some cases longer.

In order to achieve the desired interruptions within the coating, it is necessary to use materials

-I ₅ - 009819/0964

which volatilize during firing but do not adversely affect the crystallization of the glass, for example by inhibiting crystallization or by causing premature crystallization to form communicating pinholes in the coating that are in contact with the substrate. Finally, the materials should not be of a type that "spoils" in the ground ceramic slurry _{or similar after aging for several days or weeks}

It has been found that carbonaceous silicate materials are suitable for use in the manufacture of suitable formation of the roughness, which are the subject of this invention. But numerous available organic ones and inorganic materials such as clay, lithium fluoride, and organics can be used for this purpose to be useful. Indeed, any material that changes during the maturation of the covers is suitable volatilized and that does not inhibit crystal formation, forms crystals, is suitable as a nucleating agent, or does not reduce the corrosion resistance.

"16"

009819/0964

In order to achieve the advantages according to the invention, it is necessary for the bubble-forming material to volatilize, but still remain enclosed in the glass mass. Accordingly, volatilization must occur while the glass is still sufficiently viscous to overcome the pressures developed by the volatilizing gases, thereby preventing their escape and promoting the formation of bubbles. The softening point of the glass represents the lower limit at which the glass viscosity favors the inclusion of the bubbles. The upper limit is not clearly determined but can largely be characterized as the temperature at which the glass becomes sufficiently fluid to allow the volatile materials to escape. The temperature range, which is determined by the softening point, and this extremely volatile state, is generally between 54o ° C and 925 ⁰ C.

Numerous materials have been tried or used as sealing surfaces in mechanical seals. Porous materials, such as sintered brass and powdered metals, work for some Areas of application, but such materials lack the corrosion resistance as they are for numerous other areas of application is necessary. Solid ceramic bodies offer better corrosion resistance

^mll ~ 009819/09

ability than metals, but are relatively fragile and expensive. Satisfactory, with Ceramic coated metals are not readily available because of the difficulty in attempting to create a connection between the ceramic material and the metal that is strong enough to to withstand those forces which occur during use · Covered with glass Metals have heretofore given the necessary corrosion resistance, but were prior to the present invention not suitable because of the high wear rate of the surface,

The main advantage of the invention is the creation of glass coatings that combine all advantages the earlier glass «, and glass-ceramic-coated ones Materials and additionally have a previously unavailable wear resistance,

Although the surface features that are necessary to increase wear resistance create by which a surface treatment such as etching or sandblasting can be achieved the preferred method is to create roughness through all of the sheet material,

This has the additional advantage of being abrasion resistant Surface throughout

009819/0 96 4

-18-

Life of the coating material is created.

As used herein, the term glass should be interpreted to include both amorphous and crystallized or semi-crystalline glasses.

In order to have a good adhesion between different reason « To provide metal and glass coatings is a feature well known in the art using a ground coating enamel on the surface of the Metal base coatings are specially designed to an even coating over the entire ground « metal to improve and a strong bond between the surface or coating layer and the base metal to manufacture. After the above reason · « coating has been applied, one or more cover coatings are applied to it. This cover cover are formulated to create the surface features required for the particular application are. The use of base coats and top coats, both amorphous and semi-crystalline, is within the scope of the invention

Although particular methods, compositions, and milling aggregates have been described, which will be useful in practical Practice of the invention are effective, it is clear that

009819/09 6 k

the invention does not relate primarily to the compositions or the amounts of the corresponding volatile materials, but in the knowledge that a much improved wear-resistant material can be obtained by adding a surface is created that has discontinuous cavities or recesses in said surface and whereby these cavities are created without the advantageous properties of the glass or the glass « to destroy ceramic mass »

Accordingly, the specific examples and materials are illustrative and not limiting and any person skilled in the art, in the light of the description, will be able to identify the particular parameters and materials determine which best meet the requirements without departing from the scope of the invention, as set forth by the appended claims.

-20-

009819/0964

Claims (16)

Patent claims: 1. Corrosion-resistant, wear-resistant object, characterized in that that it consists of a mass of glass, which a multitude of randomly scattered, not with each other in Has connecting cavities therein and is substantially free of pinholes therethrough. 2. Article according to claim 1, characterized in that it has a smooth, flat abrasion surface, part of the said cavities intersecting this surface. j5. Object according to claims 1 or 2, characterized characterized in that said glass coating is partially crystallized, k. Article according to any one of the preceding claims, characterized in that said voids are formed by volatilization in place of a material consisting of clay, lithium fluoride or carbonaceous silicates. 5. Article according to any one of the preceding claims, characterized in that it is a metal substrate contains. 009819 / 096fc _A D original 6. Article according to claim 5, characterized in that that at least one layer of ground coating glass is melted over the metal base, at least one layer of coating glass is melted over the base coating and at least one layer of surface glass coating, the one Plurality of said randomly scattered, non-communicating cavities has over the said coating is melted over it. 7. Article according to claim 6, characterized in that said top glass coating is of the same The basic composition is like the middle coating. 8. An article according to claims 6 or 7, thereby characterized in that at least one of the glass layers mentioned is partially crystallized. 9. Article according to any one of claims 1 to 8, characterized in that it is in the form of a has improved mechanical sealing surface. 10. Method of making a corrosion-resistant An abrasion resistant article according to any one of the preceding claims, wherein a glass frit is formed and ground, where the frit.; is heated to melt, characterized in that with the ground frit finely divided particles of a BATH ORIGINAL " ² " Q09819 / Q96 * volatile material .be mixed and the mixture is heated to melt said frit and "melted the volatile material in said frit Volatilize frit, thereby forming a vitreous body containing a multitude of randomly dispersed, has non-communicating voids and is substantially free of pinholes therethrough is. 11. The method according to claim lo, characterized in that that the mixture of a Pritte of a crystallizable · Glass, which is melted and heat treated to partially crystallize the glass, 12 ". The method of claims Io or 11, characterized in that said mixture is heated to a temperature of 1000 ° F to I7OO ⁰ F to melt the genar ate Pritte. 13. The method according to any one of claims Io to 12, characterized in that said volatile material is made of clay, lithium fluoride or carbonaceous Consists of silicates. 14. The method according to any one of claims Io to 15, characterized in that the mixture is on a metal base is brought into action. 009819/0964 BATH 15. The method according to claim 14, characterized in that at least one layer on the metal base a glass base coat is melted, at least one layer of cover glass is melted over this base glass coat and a mixture is applied, which consists of a frit of the coating glass and the finely divided Particles of a liquid material are applied over the previously applied glass coating layer will. 16. The method according to claim 15, characterized in that the coating glass is a crystallizable glass is treated with heat. IJ. A method of making an improved mechanical sealing surface according to claim 9, wherein a metal base is formed in substantially the desired size and shape and a glass frit is produced, said frit being ground and said frit being applied to the metal base and heated to melt, thereby characterized in that finely divided particles of a volatile material are intimately mixed with said ground frit, and that said frit is made of crystallizable glass, after which the mixture is applied to the metal base and the mixture is heated to melt the glass, to dispose of the volatile material - ⁴ - 009819/0984 BATH ORIGINAL volatile and voids form within the glass, after which a heat treatment is applied to the glass partially to crystallize, and the wear surface of the glass is machined to create a smooth, to form flat surface and cause part of the voids formed by volatilization is exposed, whereby a substantially pinhole-free, corrosion-resistant., more abrasion-resistant Coating of high resistance with a multitude of randomly scattered unrelated ones Voids are created, some of which cut the surface. 8AD ⁵ ~ 009819/0964 Blank page