RU2730694C1 - Method for determining the vibration protection efficiency of vibration isolating couplings of marine diesel generators - Google Patents

Abstract

FIELD: measurement technology.

SUBSTANCE: invention relates to a method for determining the vibration protection efficiency of vibration isolating couplings of marine diesel generators during current and overhaul periods. Vibration of ship power plant with diesel drive is performed in two stages. First stage is performed at rigid connection of a diesel engine with a generator, and the second stage – with an elastic fastening – a vibration-isolating coupling. Difference of vibration of two stages of corresponding like points of measurement gives value of efficiency factor. At transition from one stage to another, fixing of diesel and generator feet on shelves of bearing frame, as well as attachment of vibration-isolating coupling to diesel engine and generator remain unchanged. For this purpose at the first stage measurement of vibration with operating coupling is offered. For the second stage, i.e. with rigid fixation, at least two rigid semi-cylindrical plates are used with holes along edges for fixation by fasteners to coupling flanges with previously made radial threaded sockets. Semicylindrical plates with coupling flanges form rigid cylindrical composite structure closed on all sides.

EFFECT: achieving simplicity and strength when determining the vibration protection efficiency coefficient of vibration isolating couplings.

1 cl, 4 dwg

Description

The invention relates to a method for determining the coefficient of efficiency of vibration protection of vibration-insulating couplings of marine diesel generators during periods of current and overhaul.

The invention can also be used for the main ship power plants and other shock-absorbing light and heavy objects in any field of technology.

The vibration-isolating coupling refers to non-supporting elastic connections and is an important unit that acoustically decouples the diesel engine from the generator or the main marine engine from the shafting. Its main task is to ensure the transmission of torque to the shaft while reducing the torsional, longitudinal and transverse vibration components.

The creation of an anti-vibration coupling that is effective in all three directions of vibrational components is a difficult task. According to GOST 24346-80. "Vibration. Terms and definitions "[1], the term - the coefficient of efficiency of vibration protection (hereinafter the coefficient of efficiency) is the ratio of the peak or square value of vibration displacement (vibration velocity, vibration acceleration of the protected object or the force acting on it) before the introduction of vibration protection to the value of the same value after the introduction of vibration protection ...

According to [1], to determine the efficiency coefficient of a non-supporting elastic connection, that is, a vibration-isolating coupling, it is necessary to consider the vibration measurements of a ship power plant with a diesel drive at two stages. The first stage of vibration measurement of a ship power plant with a diesel drive with a rigid connection of the diesel engine with a generator, and the second stage - with an elastic mount - a vibration-isolating coupling of a diesel engine with a generator. Subject to the same modes and operating conditions of the diesel generator, the difference in vibration of the two stages corresponding to the same measuring points will give the value of the efficiency coefficient.

However, in practice, after routine or overhaul of a diesel power plant associated with disassembly, restoration or replacement of unsuitable parts for further use, including replacing an old, failing vibration-isolating coupling with a new one, adjusting the assembly and installation, when normalizing by the maritime register, often vibration exceeds permissible standards “Russian Maritime Register of Shipping. Rules for the Classification and Construction of Sea-Going Ships Part IV. Stability ND No. 2-0201-104. SPb 2018.82 p. " (Fig. 9.2.5, d, page 42).

The purpose of the method for determining the coefficient of efficiency of vibration protection of vibration-isolating couplings of marine diesel generators during maintenance and overhaul is to ensure the simplicity and accuracy of evaluating the effectiveness of the coupling with minimal costs.

The essence of the method is that according to 1. To determine the efficiency coefficient of a non-supporting elastic connection, that is, a vibration-isolating coupling, it is necessary to measure the vibration of a ship power plant with a diesel drive in two stages. The first stage of vibration measurement is with a rigid connection of the diesel engine with the generator, and the second stage - with an elastic mount - with a vibration isolating coupling. The difference in vibration of the two stages of the corresponding measuring points of the same name will give the value of the efficiency factor. At the same time, the main distinguishing feature is that during the transition from one stage to another, the stage of fastening the legs of the diesel engine and the generator on the shelves of the supporting frame, as well as fastening the vibration-isolating coupling to the diesel engine and the generator, remain unchanged. For this, at the first stage, for example, a variant of vibration measurement with an operating clutch is proposed. For the second stage, i.e. with rigid fastening, at least two rigid semi-cylindrical plates with holes along the edges are used for fastening with fasteners to the coupling flanges with pre-made radial threaded seats. Semi-cylindrical plates with coupling flanges form a cylindrical and sufficiently rigid composite structure closed on all sides.

At the same time, to ensure the accuracy of the results obtained, it is necessary that at two stages the diesel generator works under the same conditions.

The method is illustrated by drawings, where FIG. 1 shows a general view of a diesel generator with a vibration-insulating coupling, the elastic element is made of a steel rope. The method can be applied to couplings with various elastic elements.

FIG. 2 shows the points and directions of vibration measurement.

FIG. 3 shows semi-cylindrical and narrow-cylindrical plates.

FIG. 1-4 are designated:

1 - diesel;

2 - generator;

3 - non-supporting elastic connection of the shafts of the diesel engine and the generator - vibration-insulating coupling with a steel rope elastic element;

4 - installation-bearing common frame of the diesel generator;

5 - support elastic connection of the diesel generator frame with the ship foundation 6;

6 - ship foundation;

7 - diesel flywheel;

8 - support foot of the diesel engine;

9 - cylinder block;

10 - cylinder covers;

11 - turbocharger;

12 - gas outlet compensator;

13 - turbocharger bracket;

14 - the axis of the crankshaft;

15 - the upper strip of the mounting-bearing common frame of the diesel generator;

16 - generator shaft;

17 - support foot of the generator;

18 - generator flange;

19, 22 - flanges of the cable vibration isolating coupling;

20, 21 - radial threaded sockets;

23, 24 - semi-cylindrical plates;

25-30 - holes;

31-47 - attachment points of vibration sensors along three coordinate axes.

The method for determining the efficiency coefficient of vibration-isolating couplings is carried out in the following sequence:

Install separately the diesel 1 and the generator 2 with the support legs 8, 17 on the upper strips 15 of the aggregate - bearing frame 4 with a calculated distance to accommodate the vibration isolation coupling 3 (Fig. 1);

- the vibration-insulating coupling 3 is fastened on one side 22 to the flywheel 7 of the diesel engine 1, and on the other 19 to the flange 18 of the generator 2 3;

- perform alignment of diesel 1 with generator 2;

- on the support legs 8 of the diesel engine 1, near the eye of the bolt 36 of the generator 2, on the end parts 35, 36 near the generator bearings, on the bracket 46 and the upper part of the housing 47 of the turbocharger 11, the upper part 43-45 of the cylinder covers 10, on the walls 39-41 block 9 in the area of the upper belt of the cylinder liners in the plane of the piston shifts, at the ends 42, 43 of the diesel block, as well as in other places, depending on the design features of the diesel engine 1, generator 2, clutch 3 and the type of support system 5 for damping, surfaces with threaded holes are prepared, on which vibration sensors are installed and fixed, oriented respectively along three coordinate axes;

- draw up a table indicating the attachment points of vibration sensors with the designation of the sensor number and the channel number of the device, where each specific vibration sensor is connected;

-. at the first stage, a diesel generator is started with a working elastic non-support mount - vibration-insulating clutch 3 and, after warming up, measurements are started;

- after measurements stop the diesel engine and proceed to the preparation of the second stage, i.e. with rigid unsupported fastening, in the following sequence:

- leave the mountings and positions of the diesel engine, generator, vibration isolating clutch and vibration sensors unchanged;

-. block the leading 22 and driven 19 flanges of the vibration-insulating coupling 3 (Fig. 4) by rigid fastening using at least two rigid semi-cylindrical plates 23, 24 (Fig. 2 and 3) with holes 25-30 (Fig. 2-4) along edges, through which by means of fastening means they are fixed to the flanges 19, 22 (Figs. 1, 4), in which the corresponding threaded sockets 20, 21 are preliminarily made to form a cylindrical and sufficiently rigid composite structure 18, 22, 23 closed on all sides, 24 (Fig. 4), equivalent to a rigid unsupported mount;

- according to the second stage, a diesel generator with a rigid attachment of the diesel shaft to the generator is started and measurements are started according to the plan;

- at points 36-47 of the same name, the difference between the values of the vibration level of the first and second stages of measurement is determined and the value of the desired efficiency coefficient is obtained.

The results are presented in the form of vibration spectra and analyzed. Make conclusions and make decisions.

Thus, the novelty and effectiveness of the proposed method for determining the efficiency factor of vibration-isolating couplings of marine diesel generators during the periods of current and overhaul is to ensure the simplicity and accuracy of evaluating the effectiveness of the coupling with minimal costs.

In the invariability of fastening the legs of the diesel engine and the generator on the shelves of the supporting frame, as well as the vibration-isolating coupling to the diesel engine and the generator.

Without dismantling the coupling, rigid fastening of the shafts of the diesel engine and the generator is carried out by blocking the driving and driven flanges of the coupling with cylindrical plates of the design thickness.

In the possibility of widespread use in various technical objects.

Claims (1)

A method for determining the efficiency coefficient of vibration protection of vibration-isolating couplings of marine diesel generators, characterized by the fact that the diesel engine and the generator are installed separately with the support feet on the upper strips of the aggregate bearing frame with a calculated distance, to accommodate the vibration-isolating coupling, the coupling is fastened on one side to the diesel flywheel, and, on the other hand, to the generator, they center the diesel engine with the generator, depending on the design features of the diesel engine, the generator, the clutch and the type of the damping system, install vibration sensors in the appropriate places in the threaded holes, oriented respectively along the three coordinate axes, start the diesel generator with a working elastic non-support mount - a vibration-isolating coupling and after warming up, measure the vibration, then stop the diesel, leaving the mountings and positions of the diesel, generator, vibration-isolating coupling and vibration sensors unchanged, block the driving and driven flanges of the vibration-isolating coupling gesture by fastening with the help of at least two rigid semi-cylindrical plates with holes along the edges, through which, with the help of fasteners, they are fixed to the flanges in which the corresponding threaded sockets are pre-made, with the formation of a cylindrical rigid composite structure closed on all sides, equivalent to a rigid non-supporting fastening, a diesel generator with a rigid attachment of the diesel shaft with a generator is started and the vibration is measured, the difference between the values of the vibration level of the first and second measurement stages is determined from the points of the same name, and the value of the desired efficiency coefficient is obtained.

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