DE1037269B - Shaft seal for centrifugal pumps for pumping abrasive or aggressive fluids - Google Patents

Description

GERMAN

The invention relates to centrifugal pumps which convey abrasive or aggressive liquids. she concerns the shaft seal of those centrifugal pumps.

It is known to surround the shaft with an annular chamber at the point to be sealed, the sealing lips made of rubber-like, resilient material and running at an angle to the shaft with respect to the shaft is limited. The chamber is provided with a feed line through the opposite one the atmospheric pressure under overpressure barrier liquid can flow into the chamber. As a result of the overpressure, the barrier fluid can flow through the annular gaps between the sealing lips and the shaft are formed, flow out of the chamber, so that the same is always fresher Barrier fluid is flowed through. The sealing lips are thus protected from the harmful influence of the pump fluid withdrawn.

The invention aims to provide the shaft seal of the type mentioned to achieve a more advantageous ^ u To improve embodiment of the pump.

According to the invention, the chamber is the shaft seal formed by a sleeve that consists of one piece with the sealing lips and on one Part of its axial length is designed as a plain bearing shell. Grooves are provided in that part, through which the barrier fluid is lubricated from one end to the other of the sliding surface Bearing part can flow. The shaft seal according to the invention therefore also has storage properties. This means that the previous special impeller-side bearing is no longer required. This reduces the construction effort smaller; this also reduces the overall length of the pump and, above all, the freely cantilevered one Length of the shaft towards the impeller.

The simultaneous use of a shaft seal as a shaft bearing is known per se in centrifugal pumps, which do not convey abrasive or aggressive liquids. Such known seals are through Lubricants are lubricated, but are not a barrier fluid flowing through the seal.

It is also on. known, plain bearing shells from To provide centrifugal pumps with longitudinal grooves through which part of the pump fluid flows the liquid forms the lubricating film. However, the fluids used are no sealing fluids from seals.

In an expedient embodiment of the shaft seal according to the invention, the drive-side sealing lip can be inclined obliquely towards the Kammerimiern and can be lifted off the shaft by an end of a pressure gland that tapers conically in the same direction, forming a narrow annular gap. Through a one-time I ⁷ VIn adjustment of the pressure gland shaft seal for centrifugal pumps
to promote abrasive
or aggressive liquids

Applicant:

Diebold & Cie. SA,
Nancy, Meurthe-et-Moselle (France)

Representative: Dipl.-Ing. W. Cohausz

and Dipl.-Ing. W. Florack, patent attorneys,

Düsseldorf, Schumannstr. 97

Claimed priority:
France 22 February 1954

Yves Diebold, Nancy, Meurthe-et-Moselle (France), has been named as the inventor

it is sufficient for a fine barrier fluid to escape continuously through the sealing lip on the drive side,

On the impeller side, at least one inclined towards the impeller can be used in a manner known per se Lip may be provided that acts like a ^ check valve from the pressurized barrier fluid can be lifted off the shaft with the formation of an annular gap between the sealing lip and the shaft. Through this the barrier fluid can also escape on the impeller side so that there is absolutely no contact with the rubbing or aggressive liquid from the pump with the sealing lips; needs to take place.

In the drawing, the subject matter of the invention is shown in an exemplary embodiment. It shows

Fig. 1 is a longitudinal section through a pump with a shaft seal, which is also a shaft bearing,

FIG. 2 shows a cross section along the line TI-II in FIG. 1.

As can be seen from Fig. 1, the pump consists essentially of a housing α and an impeller b on a shaft c. The entry of the shaft into the pump housing is sealed off in a liquid-tight manner by the bearing.

The storage consists of a sleeve d made of rubber, a rubber-containing mixture or a similar substance, ζ. B. plastic material, and

509 598/319

Claims (3)

closes the shaft. The sleeve d is housed in a sleeve e, which is connected to the pump housing in the manner of a projection. The sleeve e is closed by a pressure gasket /. The sleeve d has an inner ring-shaped chimney g with a supply line h for fresh water. The chamber g is closed off by a sealing lip i which is inclined towards the interior of the chamber. The chamber g ends in axially parallel grooves j. On the impeller side, the sleeve d is closed by a double sealing lip k. The device works as follows: Fresh water is fed to the chamber g at low pressure as a sealing liquid, the amount of which can be between 0.1 and several liters per minute, depending on the type of pump used. Instead of fresh water, a water-insoluble fat or any other lubricant can also be used. The sealing lip i is raised to a greater or lesser extent by the cone / the pressure gasket /. This allows a small amount of the barrier fluid to escape, which is required to lubricate the sealing lip i. The barrier liquid gets into the grooves /, through which a film that lubricates the plain bearing is created. The double sealing lip k largely reduces the leakage of the barrier liquid into the pump housing. The effect is automatic due to the negative pressure that exists at the impeller hub 1> during operation of the pump. In the case of pumps in which the fluid is supplied under pressure, the excess pressure compared to the barrier fluid presses the double sealing lip k against the shaft. This results in a liquid-tight seal so that no abrasive or corrosive substances can penetrate into the bearing. The projection of the shaft towards the impeller is reduced by about a third or up to half compared to previous pump designs. As a result of the saving of a special bearing, a pump with a bearing according to the invention requires much less space than the pumps previously used for conveying abrasive or aggressive liquids. The invention is not restricted to the exemplary embodiment described. In the context of the inventive concept, the storage can also be carried out in other appropriate ways, for. B. with regard to the design of the sealing devices, the supply and forwarding of the lubricant, PaTENTA.VS PRfCHE: 1. Shaft seal for centrifugal pumps for conveying abrasive or aggressive liquids, consisting of a chamber surrounding the shaft in a ring shape, which is limited by sealing lips which run at an angle to the shaft and are made of rubber-like flexible material and into which a pressurized barrier fluid flows and through ring-shaped Gap between the sealing lips and the shaft can flow out, characterized in that the chamber (g) is formed by a bushing (</) which consists of one piece with the sealing lips (?, K) and over part of its axial length as Plain bearing shell is formed, grooves (7) being provided in this part in a manner known per se, through which the barrier fluid can flow from one end to the other end of the bearing part while lubricating the sliding surface. 2. Shaft seal according to claim 1, characterized in that that the drive-side sealing lip (/) is inclined towards the inside of the chamber and by an end of a pressure gasket (/) that tapers conically in the same direction to form a narrow annular gap can be lifted off the shaft. 3. Shaft seal according to claim 1 or 2, characterized in that on the impeller side in a manner known per se at least one sealing lip (A ') inclined towards the impeller (b) is provided. which, like a check valve, can be lifted off the shaft from the pressurized barrier fluid, forming an annular gap between the sealing lip and the shaft. Considered publications: German patent specifications No. 851 630, 496 784.
029; German patent application M 11605 Ia / 59b (announced on October 9, 1952); French Patent No. 1,059,878; U.S. Patent Nos. 2,303,232, 2,286,425.
869 955. 1 sheet of drawings ® 809 5 * 8/319 8.53