SU436923A1 - Compressor indication method - Google Patents

Description

one

The invention relates to the field of compressor engineering and concerns the measurement of gas parameters in the working cavities of compressors, mainly screw ones.

There is a method of indicating a screw compressor by placing sensors in the working cavities with signals on an oscilloscope screen.

The purpose of the invention is to simplify the continuous measurement of gas parameters in the working cavities of the compressor.

This is achieved by the fact that the signals are received on the same scale, they are combined on the screen of the oscilloscope, and the true value of the parameter is determined from the external contour of the combined curves.

The described method is illustrated by the example of a screw compressor.

FIG. Figure 1 shows a compressor with the working cavity L under study on the suction side, a cross section; in fig. 2 - scan of the bastard L and the sensors located in it; in fig. 3 shows the position of the cavity L at the place of installation of the first downstream sensor; in fig. 4 is the same for the middle sensor; in fig. 5 - the same for the latter along the sensor flow; in fig. 6 - change of the parameter being studied (pressure) during the turn of the first sensor along the flow of an angle of 2; in fig. 7 is the same for the middle sensor; in fig. 8 - the same for the latter along the sensor flow; in fig. 9 shows the combined sensor signals for the time of rotation of the rotor at an angle fprots.

The screw compressor contains a master 1 and a slave 2 rotors placed in the housing 3 with the test cavity L, in which the first sensor 4 is installed along the flow path, the middle sensor 5 and the last sensor 6 along the flow path.

In the drawings, the following symbols are used:

TI - twist angle leading rotor;

L - the height of the working cavity; a is the angle of rotation of the rotor;

t - the number of teeth of the leading rotor ;.

PB = suction pressure;

Рп - discharge pressure.

To implement the described method of indication, the number of sensors necessary for their installation in the working cavities of the screw compressor is determined by the formula:

f

percent

TO

2G .-- 1

where: k

- the number of sensors; Flrots is the angle of rotation of the rotor corresponding to the duration of the process in the same cavity;

7 - the angle of rotation of the rotor, according to the time of overlapping of the parts of the process, fixed by different and sensors.

Angle Y lies in the range

2-

where m is the number of rotor teeth.

Each sensor fixes a part of the process that takes place in the entire cavity A in the course of one revolution or at the angle of rotation 2p. The beginning of the fixation process corresponds to the moment when the sensor intersects the OiOz line (see Figs. 3, 4 and 5), since at this moment the sensor from the compression area enters the suction area.

FIG. 3, 4, 5, the dotted line shows the position of cavity A at the place of installation of sensors 4, 5 and 6 at the time of the beginning of the fixation process (view from the suction window). The position of cavity A in the suction window is shown by a contour line, and the darkened area of the suction window corresponds to that part of the suction process that the corresponding sensor records.

During one revolution of each sensor (see Figs. 3, 4 and 5) some part of the compression and extrusion process is fixed, however, the ratio of these parts for each sensor is different. Thus, sensor 4 mainly records the process of suction and transfer of the working fluid, and the process of compression is only partially. Sensor 5,

mounted in the middle of cavity A, fixes a part of the suction process, the whole compression process and a part of the ejection process. Sensor 6, mounted close to the end of the head, basically detects the process of compression and ejection.

The change curves of the measured parameter, recorded by the sensors 4, 5 and 6, are arranged on the oscilloscope screen in a specific order and looked as shown in FIG. 6, 7 and 8.

In order to determine the continuous value of the working body parameter being studied, the signals received from each sensor lead to

one scale, smoothly changing the gain of the oscilloscope, and then combining them. FIG. 9, curve 7 is the outer contour of superimposed curves, it is more convenient to reduce all curves to the scale of sensor 6.

Subject invention

A method for indicating a stressor, preferably a screw one, by placing it in

working cavities of the sensors with signals to the oscilloscope screen, characterized in that, in order to simplify the continuous measurement of gas parameters, the signals are received at the same scale, they are combined on the screen

The oscilloscope and the true value of the parameter are determined from the outer contour of the aligned curves.

Fig 5

Fig 9