RU176575U1 - SHAFT SEAL - Google Patents

Abstract

This utility model relates to the field of mechanical engineering, namely, to shaft seal designs. The shaft mechanical seal contains a movable friction ring, a fixed friction ring, an elastomeric sleeve made with a through hole for the shaft, two retaining rings provided with teeth, a compression spring installed between the retainer rings, a pressure washer for fixing the stationary friction ring, in the movable friction ring , on its outer diameter, a groove is made, the retaining rings are made with elongated flanges, while the movable and fixed friction rings are made of an alloy of cast tungsten carbide with copper. The mechanical shaft seal has increased reliability and extended service life. 7 c.p. f-ly, 5 Fig.

Description

Technical field

 The utility model relates to the field of mechanical engineering, namely to the designs of mechanical shaft seals.

State of the art

A mechanical shaft seal is known, including a thrust ring and a movable friction ring located on the shaft with cylindrical bores facing each other, an axial cylindrical spring placed between them with pinched and unpolished end turns, transmitting torque from the thrust ring to the movable friction ring and compressing it to a fixed one installed in the housing, as well as cuffs made of elastic material, mounted in cylindrical bores of the thrust ring and the movable friction ring with the possibility of their interaction with the last and extreme turns of the axial spring (patent RU No. 2095668 C1, IPC: F16J 15/34, published 10.11.1997, Joint-Stock Company Machine-Building Plant).

The disadvantage of this solution is the simultaneous fulfillment by the spring of three functions: 1) ensuring the tension of the moving friction ring to the stationary one, 2) the transmission of torque to the moving friction ring from the thrust ring, 3) the necessary sealing on the shaft by pressing the cuffs from elastic material into the cylindrical bores of the thrust rings and a movable friction ring due to the radial load created during assembly by tightened and unpolished extreme turns of the spring.

The closest known technical solution (prototype) is the support pressure unit of the mechanical shaft seal (patent RU 167 896 U1, IPC: F16J 15/34, published January 11, 2017, Limited liability company PK Remelectropromneft).

 The assembly comprises a sleeve made of elastomer with an axial through hole for positioning the shaft therein. On the outer surfaces of the sleeve made two ring collars. An annular recess is made at one end of the sleeve, in which a sealing ring is installed. The assembly also contains two retaining rings made of metal, and a cylindrical compression spring installed between the retaining rings. The retaining rings are equipped with teeth.

The disadvantages of this technical solution are that the torque from the driving element, rigidly connected to the shaft, is transmitted to the driven element through a spring, metal retaining rings, an elastomer sleeve, into which a sealing ring is inserted, fixed only by an elastomer sleeve, which does not allow reliable fixing O-ring in the sleeve, which directly transfers the torque from the shaft.

In the above technical solutions, the springs experience significant loads, the movable o-rings are subject to displacement, the rigidity of the transmission of torque from the shaft to the movable o-ring is not ensured, the working surfaces of the o-rings are subject to overheating and destruction, which leads to premature failure of the mechanical seal.

An urgent technical problem lies in the need to create a mechanical shaft seal with increased reliability and extended service life.

Summary of utility model essence

In one aspect, the utility model discloses a mechanical seal comprising a fixed friction ring, a movable friction ring, wherein a groove is made on the movable friction ring, an elastomeric sleeve made with a through hole for positioning the shaft, two retaining rings provided with teeth, while the retaining rings are made with elongated flanges, a compression spring installed between the retaining rings, a pressure washer for fixing the stationary friction ring, while the movable and stationary friction rings are made of alloy cast tungsten carbide with copper, elastic cuff.

In another aspect, a utility model discloses a diameter of a groove made on a movable friction ring of a mechanical seal of 0.5-1.5 mm. In another aspect, the utility model discloses that the groove is in a semicircular shape.

In another aspect, the elastomeric sleeve is made of a heat-resistant elastomeric material.

In another aspect, the utility model discloses that the retaining rings are metal retaining rings.

In another aspect, the utility model discloses that a pressure washer is made of stainless steel.

In another aspect, the utility model discloses that a pressure washer is made of brass.

In another aspect, the utility model discloses that a fixed friction ring comprises a groove located along the outer diameter of the ring.

The technical result of this utility model is to increase reliability and increase the service life of the mechanical shaft seal.

Increased reliability and increased service life of the shaft mechanical seal are achieved by: making a groove in the movable friction ring of the mechanical seal along its outer diameter, which provides an increased contact area of the moving friction ring with the elastomeric sleeve, thereby preventing displacement of the moving friction ring; making retaining rings with elongated flanges, ensuring proper fit of the elastomeric sleeve along elongated flanges, which provides more reliable fastening of the moving friction ring, while increasing the rigidity (reliability) of the transmission of torque from the shaft to the moving friction ring; the use of a clamping washer for fixing the stationary friction ring, preventing the motion of the stationary ring, and providing unloading of the spring, which reduces the axial load on the friction pair; making movable and fixed friction rings from an alloy of cast tungsten carbide (relite) with copper, which prevents overheating and destruction of the working surfaces of the friction rings in the event of short-term "dry" friction. The above advantages provide increased reliability of the mechanical seal of the shaft as a whole, and as a result, increased life of the mechanical seal of the shaft.

Brief Description of the Drawings

The scale of the components in the drawings may differ from the real one.

In FIG. 1 shows a longitudinal section of a portion of a shaft mechanical seal including an elastomeric sleeve, a movable friction ring, retaining rings, a spring (shaft not shown);

In FIG. 2 shows an enlarged sectional view of a portion of the mechanical seal of FIG. 1, including a groove made on the outer diameter of the movable friction ring;

In FIG. 3 shows a partial sectional view of a portion of a shaft mechanical seal showing an elongated collar of a retaining ring;

In FIG. 4 is a view of a first embodiment of a portion of a shaft mechanical seal in longitudinal section, including a fixed friction ring, a pressure washer for fixing the fixed friction ring, an elastic sleeve.

In FIG. 5 is a view of a second embodiment of a portion of a shaft mechanical seal in longitudinal section, including a fixed friction ring, a pressure washer for fixing the fixed friction ring, an elastic cuff.

Detailed Description of Embodiments of a Utility Model

The mechanical seal 1 of the shaft contains an elastomeric sleeve 10 with an axial through hole for the location of the shaft (the shaft is not shown), which ensures the tightness of the mechanical seal with permissible axial movements of the shaft. The sleeve may be made of various heat-resistant elastomers known to a person skilled in the art. The retaining rings 3, 4 are provided with teeth and are put on the elastomeric sleeve on both sides so that the teeth of each of the retaining rings are directed towards each other. The retaining rings 3,4 contain elongated flanges ensuring a proper fit of the annular edges of the elastomeric sleeve (Fig. 1). The retaining rings may be made of metals, alloys, and other suitable materials known to those skilled in the art. Between the retaining rings installed spring 5 compression. The movable friction ring 2 is installed in the recess at the end of the elastomeric sleeve 10. The annular edges of the elastomer sleeve are located in the elongated shoulders of the retaining rings 3.4, which ensures the immobility of the elastomer sleeve in the radial direction and allows you to create the necessary interference when installing the movable friction ring 2 in the elastomeric sleeve 10 , and also prevents the rotation of the movable friction ring 2 relative to the elastomeric sleeve 10 when transmitting torque from the shaft (Fig. 1).

To increase the reliability of fastening the movable friction ring 2 in the elastomeric sleeve 10, in the movable friction ring 2, a groove 11 is made along its outer diameter (Fig. 2). The groove 11 may have a semicircular, triangular, rectangular shape.

The necessary dimensions of the groove 11 are selected by a specialist based on the dimensions of the mechanical seal and the diameter of the shaft. For example, the diameter of the semicircular groove may be 0.5-1.5 mm, in particular 0.8 mm, in the case of an mechanical seal for a shaft with a diameter of 25 mm.

The groove 11 in the movable friction ring 2, according to its outer diameter, allows to increase the contact area between the elastomeric sleeve 10 and the movable friction ring 2, prevents axial movement of the movable friction ring 2 in the elastomeric sleeve 10, and also prevents the rotation of the movable friction ring 2 relative to the elastomeric sleeve 10. The presence of elongated flanges of retaining rings 3.4, as well as grooves 11, made in a movable friction ring 2, along its outer diameter, significantly increases the reliability before chi torque from shaft 2 to the movable ring of friction.

The fixed friction ring 6 of the shaft mechanical seal is fixed from axial movement by the pressure washer 8 (Fig. 4, Fig. 5). The washer may be made of stainless steel or brass, or any other suitable material known to the person skilled in the art. The dimensions of the pressure washer are selected by a specialist based on the overall dimensions of the shaft mechanical seal. For example, for the mechanical seal of a shaft, the diameter of which (of the shaft) is 25 mm, the thickness of the pressure washer may be 0.5-1.5 mm, in particular 1 mm.

The use of the clamping washer 8 for fixing the stationary ring of the friction pair significantly unloads the compression spring 5, and accordingly the annular friction pair itself. In this case, the compression spring only creates the necessary tightness to ensure tightness between the movable friction ring 2 and the stationary friction ring 6, and does not perform the function of fixing the stationary friction ring 6 from axial displacement relative to the equipment body in which the shaft mechanical seal is used.

The use of the clamping plate 8 for fixing the stationary friction ring 6 also makes it possible to use a weaker spring and reduces the axial load on the annular friction pair, increases the reliability of the annular friction pair (movable friction ring 2 and the stationary friction ring 6), and increases the life of the end face seals.

The tightness of the connection of the stationary friction ring 6 with the flange or body of the equipment 9, in which the mechanical shaft seal is used, can be ensured by means of an elastic sleeve 7 (Fig. 4, Fig. 5).

In one embodiment, an elastic cuff may be mounted under a fixed friction ring (FIG. 4).

In one of the embodiments, the elastic cuff 7 is installed in the groove made on the outer diameter of the stationary friction ring 6 (Fig. 5).

In the mechanical seal, the movable and fixed friction rings 2, 6 are made of an alloy of cast granulometric tungsten carbide (relite) with copper. When short-term “dry” friction occurs, copper performs the function of lubrication between the movable and fixed rings of 2.6 friction, preventing overheating and destruction of the working surfaces of the friction rings. This significantly increases the reliability and service life of the mechanical seal.

This utility model provides a reliable mechanical shaft seal with extended service life.

Claims (8)

1. The mechanical seal of the shaft, containing a movable friction ring, a fixed friction ring, an elastomeric sleeve made with a through hole for the shaft, two retaining rings provided with teeth, a compression spring installed between the retaining rings, an elastic cuff, characterized in that it contains a clamp a washer for fixing the stationary friction ring, in the movable friction ring, along its outer diameter, a groove is made, the retaining rings are made with elongated flanges, while the movable and fixed ring The friction is made of an alloy of cast tungsten carbide with copper. 2. The seal according to claim 1, characterized in that the diameter of the groove is 0.5-1.5 mm. 3. The seal according to claim 2, characterized in that the groove has a semicircular shape. 4. The seal according to claim 1, characterized in that the elastomeric sleeve is made of heat-resistant elastomeric material. 5. The seal according to claim 1, characterized in that the retaining rings are metal retaining rings. 6. The seal according to claim 1, characterized in that the pressure washer is made of stainless steel. 7. The seal according to claim 1, characterized in that the pressure washer is made of brass. 8. The seal according to claim 1, characterized in that the stationary friction ring contains a groove located along the outer diameter of the ring.

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