RU2393471C1 - Method and device for determining content of insoluble residues in spent oil - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: in the method which involves centrifuging a prepared oil solution and subsequent suspension of the obtained residue, deposition takes place in a thin annular layer of the oil solution which rotates together with a rotor. Centrifugation is done once and decantation of the centrifuge effluent is done automatically when the centrifugal rotor stops. In the device which has a housing, an electric motor with a vertical shaft, the rotor is made in form of a reservoir with a removable cover, in which there are two cavities for putting the analysed oil solution, depositing impurities and decantation of the centrifuge effluent. The rotor also has a removable cylindrical insert made from metal foil for collecting residues which undergoes control weighing. The rotor is driven by the shaft of the electric motor through an overrunning centrifugal clutch which automatically connects them in startup and centrifugation mode and also disconnects when the electric drive is switched off, thereby providing smooth free run-out of the rotor with the filtered centrifuge effluent.

EFFECT: increased accuracy, simplification and faster determination.

3 cl, 1 dwg

Description

The invention relates to a technology for determining the content of solids in petroleum products, in particular to methods and devices for determining insoluble sediments in spent mineral, hydraulic, transformer and other oils, and can be used in various fields of science and production.

A known method for the determination of mechanical impurities / 1 /, used for oil, liquid petroleum products and additives. It consists in filtering the test products, previously dissolved in gasoline or toluene, through a membrane filter, washing the precipitate obtained on the filter with a solvent, followed by drying and weighing. The pollution content is calculated by the difference in the mass of the filter before and after filtration. To accelerate the filtration, it is allowed to conduct it under vacuum.

The disadvantages of the method are its low accuracy, significant measurement errors, the long analysis time and its complexity.

Closest to the claimed method is a method for determining the content of insoluble precipitates / 2 /, distributed to motor waste oils. Its essence consists in 10-fold dilution of the metered mass of oil placed in a test tube with a solvent containing a coagulant, centrifugation of the test tube with the resulting solution for at least 1 hour with periodic verification of the purity of the obtained centrate. Next, the solution is decanted. The solvent is re-placed in the tube with the resulting pellet and centrifuged again. This operation is repeated until the desired purity of the centrate is achieved. Then the tubes with sediment are dried and weighed. The difference in the mass of the test tube before and after the experiment determines the mass of precipitated precipitate.

The disadvantages of this method are its low accuracy, measurement errors, a long centrifugation time, a significant duration and the complexity of the analysis due to the repeated processes.

Closest to the claimed device is a laboratory benchtop centrifuge / 3 /. It consists of a base, a housing with a cover, a drive with an electric motor. The rotor of the angular type RU 180L / 4 / is rigidly attached to the shaft of the electric motor located vertically. The rotor has a number of blind holes located symmetrically in the radial planes in which the tubes with the analyzed liquid are placed at an angle to the axis of rotation. The operation of the device consists in centrifuging small volumes of liquid placed in test tubes. Moreover, the rotor speed is limited by the tensile strength of the tubes, as well as the difficulty of ensuring its accurate balancing.

The disadvantage of this centrifuge is the design complexity, low separation efficiency, and a long centrifugation time.

The objective of the invention is to increase the accuracy of determination of precipitation, reduce measurement errors, while simplifying the technology and design, as well as reducing the overall time and complexity of the process.

The problem is achieved in that in the method for determining the content of insoluble sediments in used oils, including centrifuging the prepared oil solution, decanting the centrate followed by weighing the obtained sediment, deposition occurs on a cylindrical metal foil insert concentrically installed in the upper cavity of the rotor in a thin ring layer rotating together with the rotor of the oil solution obtained by overflowing the oil solution from the lower cavity of the rotor to the upper, centrifugation made once, and decantation of supernatant is performed automatically in the process of stopping the centrifuge rotor.

The problem is solved in that in the device for determining the content of insoluble sediments in waste oils containing a rotor mounted on a vertically arranged shaft connected to the motor shaft, the rotor is a reservoir with a removable cover and consists of a lower cavity for accommodating the test fluid made in in the form of a truncated cone, facing upward with a large base, and the upper cylindrical cavity to accommodate the decanted centrate and precipitate impurities with a diameter exceeding m diameter of the top by the underside of the cavity, wherein the upper cavity concentrically installed designed checkweighing removable cylindrical insert metal foil for collecting precipitation, whose height corresponds to the height of this cavity. In addition, the rotor drive is carried out from the motor shaft through an overrunning centrifugal clutch, which automatically connects them in the start-up and centrifugation modes, and also disconnects them at the moment the electric drive is turned off, providing a smooth free-running mode of the rotor with a filtered centrifuge.

The invention is illustrated in the drawing, which schematically shows the proposed device and one of its sections.

The device consists of a rotor 1 mounted on a vertically located shaft of the rotor 4, which is connected to the shaft of the electric motor 2 by a centrifugal clutch 3. The shaft of the rotor 4 is mounted on two ball bearings 5 in the housing 6 of the device. On top of the rotor 1 is closed by a removable cover 7, pressed by a nut 8. The rotor 1 has two cavities: the lower A and upper B. The lower cavity A has the shape of a truncated cone, facing up with a large base. The upper cavity B is cylindrical, its diameter exceeds the diameter of the upper larger base of the cavity of lower A. In the upper cavity B, a concentrically removable cylindrical insert 9 of metal foil is installed. Its height corresponds to the height of this cavity.

One-way centrifugal clutch 3, the cross section of which AA is shown in the drawing, consists of a leading coupling half 10, a driven coupling half 11, two blocks 12 and a tension spring 13. The pads 12 are pivotally attached to the end face of the driving coupling half 10 mounted on the shaft of the electric motor 2 and are tightened interconnected by a spring 13. The driven coupling half 11, rigidly connected with the shaft of the rotor 4, is a drum, inside of which the pads 12 are placed with a gap.

The method for determining the content of insoluble precipitates using the device described above is as follows.

A measured portion of the test oil, previously diluted with a solvent with the addition of a coagulant in a ratio of 1: 10, is placed in the lower cavity A of the rotor 1 of the device. A pre-weighed removable cylindrical insert 9 of metal foil is installed in its upper cavity B. The rotor 1 is driven into rotation and the liquid in it is subjected to centrifugation for a regulated time. After that, the device stops, a removable cylindrical insert 9 with the collected sediment is removed, dried in an oven, cooled and weighed. The difference in mass of the removable cylindrical insert 9 before and after the tests determines the amount of insoluble sediment contained in the initial sample of oil.

Implementation of the proposed method is carried out using a device whose operation is as follows.

When the device is turned on, the shaft of the electric motor 2 is rotated, the pads 12 located on the driving half of the drive 10 diverge under the action of centrifugal forces, stretching the spring 13, and are pressed against the inner cylindrical surface of the driven half of the coupling 11. As a result, the bypass centrifugal clutch 3 is blocked and the rotor 1 driven into rotation. The processed fluid located in the cavity A, rotating together with the rotor 1, is poured into the upper cavity B by the action of centrifugal forces, located there in the form of a thin cylindrical layer. Here, from the liquid, particles of insoluble precipitation are deposited on the inner surface of the removable cylindrical insert 9.

After turning off the device, the shaft of the electric motor 2 quickly stops together with the leading coupling half 10 of the drive. Under the action of the coupling spring 13, the pads 12 converge and the freewheel centrifugal clutch 3 is unlocked. The rotor 1 of the liquid device continues to rotate by inertia. Due to the significant moment of inertia and low resistance of the air and thrust bearings 5, its long free run-out is ensured. Smooth braking of the rotor 1 eliminates the flushing of insoluble precipitates deposited on a removable cylindrical insert 9 with a filtered centrate. As the angular velocity of the rotor 1 decreases, the centrifugal field strength decreases and the centrate from the upper cavity B gradually flows back to the lower cavity A under the action of gravity.

The advantages of the proposed method and device for its implementation are as follows.

Centrifugal sedimentation of insoluble impurities from the test oil solution is carried out directly in the cylindrical cavity of the rotor of the device, which allows in comparison with the known method to increase the volume of the tested oil by 8 ... 10 times. At the same time, the amount of insoluble precipitation contained in it increases proportionally and, accordingly, the accuracy of the measurements made increases.

Precipitation of insoluble impurities occurs in a thin annular layer of oil rotating together with the rotor. This allows you to provide a minimum path of deposition of particles, thereby increasing the efficiency of the allocation of insoluble sediments and reduce the time of centrifugation.

The separation of the purified centrate from the precipitate (decantation) after centrifugation is carried out spontaneously without the participation of the operator: as a result of the mutual action of the centrifugal and gravitational fields on the liquid during the smooth stop of the centrifuge rotor.

In addition, the centrifugation and decantation of the test fluid is carried out only once. Due to this, the complexity of the process is reduced.

The use of a removable cylindrical insert from a metal foil as a part onto which impurities are deposited and which is subjected to control weighing makes it possible to reduce measurement errors due to its low mass.

The design of the rotor of the device allows for uniform distribution of the processed fluid along the periphery of its working cavity during rotation, thereby achieving a high balance of rotating parts. Due to this, centrifugation is carried out at high speed and the separation factor of the test fluid. This allows you to reduce the time of deposition of particles, and therefore, the total time of the process of determining the content of insoluble sediments in industrial oils.

Information sources

1. GOST 6370-83 Petroleum, petroleum products and additives. Method for determination of solids.

2. GOST 20684 - 75 Engine used oils. Method for determination of insoluble precipitation. - The prototype.

3. Centrifuge, laboratory bench-top TsLN-2. Passport. SHX2.779.014. - The prototype.

4. Rotor angular RU 180L. Passport. SHX4.078.009-03 Substation.

Claims (3)

1. The method of determining the content of insoluble sediments in waste oils, including centrifuging the prepared oil solution with subsequent weighing of the obtained precipitate, characterized in that the deposition takes place on a cylindrical metal foil insert concentrically installed in the upper cavity of the rotor in a thin ring layer of the oil solution rotating together with the rotor obtained by pouring an oil solution from the lower cavity of the rotor to the upper, centrifugation is performed once, and decanting the centrate is carried out automatically in the process of stopping the centrifuge rotor. 2. A device for determining the content of insoluble sediments in waste oils, comprising a rotor mounted on a vertically arranged shaft connected to an electric motor shaft, characterized in that the rotor is a reservoir with a removable cover and consists of a lower cavity for receiving the test fluid, made in the form a truncated cone, with the large base facing up, and the upper cylindrical cavity to accommodate the decanted centrate and precipitate impurities with a diameter greater than the diameter of the upper th lower base of the cavity, wherein the upper cavity designed to set checkweighing removable cylindrical insert metal foil for collecting precipitation, whose height corresponds to the height of this cavity. 3. A device for determining the content of insoluble sediments in waste oils according to claim 2, characterized in that the rotor is driven from the motor shaft through an overrunning centrifugal clutch, which provides automatic connection of the motor shafts and the rotor in the start-up and centrifugation mode, as well as their separation the moment the device is turned off, providing a smooth free-running mode of the rotor with a filtered centrifuge.

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