SU1758324A1 - Method of measuring contact loading of shaft flexible seal edges and device for effecting same - Google Patents

Abstract

This invention relates to the performance monitoring of elastic shaft seals. The purpose of the invention is to expand the operational capabilities by rigidly fixing the edge at a given amount of deformation and keeping it in this position at the required time intervals, as well as improving accuracy. The device for carrying out the method comprises a shaft simulating a sealable, consisting of a stationary part 1, made in the form of a glass with a through window 2, fixed to the base plate 3. The movable part 4 is held by a screw 5. The internal cavity of the shaft is sealed using a cover b and connected by pipeline 7 through valve 8 to a source of compressed gas. A measuring device 9 is connected to the pneumatic actuator main. A ring 10 is fitted on the outer surface of the shaft, a removable support 11, a discharge valve 12, a rod 13 are mounted on the support plate 3. The valve 12 is connected to the outlet 14 of the pneumatic system in which the throttle 15 is installed. gas in the pneumatic actuator, the ring 10 is raised along the shaft and mounted on the support 11. With the valve 12 closed through the valve 8, the pneumatic system is filled with compressed gas at an excess pressure exceeding

Description

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1

The necessary balancing of the soda and the sealant is removed. The support 11 is opened. The valve 12 is opened, and the compressed gas is released. When the gas pressure reaches a value that balances only the seal edge load, the ring 10 is released, lowers along the shaft, and the valve 12 is closed, stopping further gas release. gas is measured by the device 9. 2 c pf-ly, 3 silt

This invention relates to the control of the performance characteristics of elastic shaft seals, which are widely used in various fields of engineering (mechanical engineering, automobile construction, aviation, etc.),

The aim of the invention is to expand the operational capabilities by rigidly fixing the edge at a given amount of deformation and keeping it in this position at the necessary time intervals, as well as improving the accuracy,

FIG. 1 shows a device for measuring contact load; in fig. 2 is a diagram of an implementation of a method for measuring a contact load of an edge of a seal and a force acting on a movable part of an oscillator; FIG. 3 shows graphical dependences of the change in the load on the edges of a seal with time obtained by implementing this method on the device.

A device for carrying out the method of measuring the contact load of the edges of the seals comprises a mandrel simulating a shaft to be compacted and a pneumatic actuator. The mandrel consists of two parts. The fixed part 1 is made in the form of a glass with a through window 2 in the side wall, which is fixed bottom up on the base plate 3. The movable part 4, filling the through window 2, is made in the form of an element of a cylindrical ring and is installed in the through window of the fixed part of the mandrel with movement in the radial direction. The movable part 4 is prevented from falling out of the window 2 when the device is transported by the screw 5. The possibility of moving the movable part in the glass window is ensured by the difference in the diameters of the hole in the movable part 4 and the screw 5. The internal cavity of the shaft is sealed (for example, by installing a rubber boot 6) connected by pipeline 7 through valve 8 to a source of compressed gas (not shown). A measuring device 9 is connected to the pneumatic actuator main. A cylindrical calibration ring 10 with a sliding fit is fitted onto the outer surface of the shaft, allowing the calibration ring to be lowered along the shaft under its own weight. A removable support 11 is installed on the support plate 3, which allows the calibration ring 10 to be mounted with the mating part 4 of the mandrel and the pneumatic discharge valve 12 so that the calibration ring 10 lowered along the shaft acts on the valve stem 13 and closes it. channel 14 of the pneumatic system, in which the choke 15 is installed, providing a constant

rate of discharge of the pneumatic actuator. A seal 16 is mounted on the shaft and an edge, the load of which is measured, is placed on the movable part 4.

The method of measuring the magnitude of the contact load of the sealing lip is carried out as follows.

In the absence of gas pressure in the pneumatic actuator, the calibration ring 10 is raised over the mandrel and set to

removable support 11. The orientation of the edge in a plane perpendicular to the shaft axis is provided by the upper end surface of the calibration ring 10. When the discharge valve 12 is closed through valve 8

the pneumatic system of the device is filled with compressed gas at an excess pressure exceeding that required to balance the load on the edge of the sealer. Compressed gas fills the internal cavity

the mandrel acts on the movable part 4 and moves it in the radial direction against the stop into the calibration ring 10, thus deforming the sealing edge to the one specified by the calibration ring

magnitude. The support 11 of the calibration ring 10 is removed, which is now held in this position by pressing it against the movable part 4 of the mandrel. Open the discharge valve 12, release the compressed gas from

pneumatic system, which is accompanied by a decrease in the force acting on the calibration ring from the side of the movable part and holding it in this position. When the gas pressure reaches

balancing only the edge loading of the seal, the calibration ring 10 is released, descends along the mandrel, closes the unloading valve, stopping further gas release.

The measured gas pressure is measured with instrument 9.

Fig. 2 shows the forces acting on the movable part of the mandrel when it is pressed by the gas overpressure to the calibration ring and thus fixed in the position corresponding to the nominal shaft diameter. The gas, compressed to pressure q, acts on the inner surface of the movable part of the mandrel, whose area S is constant, creating a force P q-S. From the outer side, the moving part 4 is acted on by the force Q, created by the edge of the seal 16, and the force R is the response of the calibration ring 10. then, and the gas pressure q that creates it on the movable part can be represented as two independent terms of the pressure qi and qa. The gas pressure qi creates a force Pi qrS, balancing the load Q of the sealing edge, and the gas pressure qa creates a force 2 - q2 -S, (Pa R) pressing down the movable part 4 to the calibration ring 10 and is an excess part of the pressure.

The magnitude of the gas pressure q is directly proportional to the force created by the loading of the sealing lip Q qi-S. This gas pressure can be determined by direct measurement with the device included in the device pneumatic system, after unloading it from the excess part of the pressure q2. This is achieved as follows. Opening the valve 12, the excess pressure part q2 is released from the pneumatic system, which is accompanied by a decrease in the force Pz R holding the calibration ring 10 in conjunction with the movable part 4 of the mandrel. At the time the pneumatic system is unloaded from the excess part of the pressure, the calibration ring is released and, on the mandrel, acts on the rod 13 of the valve 12. Closes the valve and stops further reduction of the gas pressure. The gas pressure recorded in the pneumatic system balances only the force Q of the edge load. The magnitude of this pressure is measured by instrument 9.

Under the load N of the sealing lip or its contact pressure, it is customary to understand the magnitude of the force per unit length of the shaft circumference (linear radial force or load).

Taking this into account and the constancy of the geometry of the moving part 4 of the device, i.e. its internal area S, perceiving gas pressure and the length I of the outer cylindrical surface in contact with

the edge of the seal, the magnitude of the load of the N edge and the pressure q, aeg.1 can be expressed by the dependence

N -Q1-S

where N is the contact load of the sealing edge, kgf / cm;

S is the area of the inner surface of the moving part of the shaft, cm2;

I - the length of the outer surface of the movable part of the shaft, cm;

q1 is the gas pressure in the device pneumatic drive, kgf / cm2.

The S / I ratio is nothing like

the constant of the device, which is a coefficient of proportionality, connecting the values of gas pressure and edge load. The considered features of this device show that it allows one to go from determining the load of the sealing edge to its direct measurement, while eliminating the need for its calibration and adjustment. To simplify the use of the device on the scale of the device 9 (reference pressure gauge) included in the pneumatic system, taking into account the proportionality coefficient S / I (constant device), the loading edge of the seals was additionally calibrated.

For example, the Calibration ring was lifted along the shaft prior to mating with the moving part and mounted on a removable support.

A seal was put on the mandrel and an edge was placed, the load of which was measured on the movable part of the mandrel. Through valve 8, the pneumatic actuator was filled with gas at an overpressure, the ring support was removed and

immediately opened the discharge valve. Gas was vented from the pneumatic system, the calibration ring fell and the unloading valve was closed. After that, read the instrument 9.

Thus, the initial value of the edge load was determined, i.e. load arising at the time of deformation of the edge of the movable part of the mandrel. Then the ring was again raised to the initial position, the gas overpressure was established in the pneumatic actuator and the ring support was removed. In this position, the device was held, adopted for the study of the relaxation of the loads of the edges of the seals,

a time interval (one hour) and only after that the discharge valve was opened, the wire measuring the contact pressure that had become stable during this time. Subsequent measurements made

in a similar way, while increasing

time of the edge in the deformed state by the value of the received interval The data on the relaxation of the working edge of the seal of the type 2-60x85-2 obtained in this way are shown in FIG. 3, Curve I depicts the change in the load of the working edge without a spring; curve II is the change in the working edge load with the bracelet spring installed.

Claims (2)

Claim 1. Method of measuring the contact load of the edges of the elastic shaft seals, including putting a seal on a mandrel consisting of a fixed part and a movable part with a pneumatic actuator, supplying compressed gas to a pneumatic actuator, measuring gas pressure, characterized in that. in order to expand the operational capabilities and improve accuracy, preliminarily with mating with the movable part of the mandrel, the edge deformation limiter is positioned and fixed, compressed gas is supplied to the pneumatic actuator until the deformation limiter is fixed by pressing the moving part of the mandrel to it, then it is released from the drive excess gas until the strain relief is released and the gas pressure is measured. 2 2. A device for measuring the contact load of the edges of the elastic seals of the shaft, containing a mandrel mounted on the base plate in contact with test seal and consisting of a fixed part and a movable part with a pneumatic actuator connected to a source of compressed gas with a discharge valve, characterized by that, in order to expand operational capabilities and improve accuracy, the device is equipped with a calibration ring with a removable support, the fixed part is made in the form of a rigidly mounted on base plate bottom up the glass with a through window in its side wall, while the movable part of the mandrel is installed in the through window with the ability to move in the radial direction and made in the form of a cylindrical ring, the inner cavity of the glass is sealed and connected to a power source with compressed gas, and a calibration ring is installed on the outer surface of the glass under the action of its own weight, with a removable bearing of the calibration ring mounted on the supporting plate, which holds the latter with a movable coupling parts mandrels, and unloading valve with the possibility of interaction of the valve stem with the calibration ring. Rk KG1 5sr 0.6 0.5 0.4 0.5 0.20, 1