RU79181U1 - FLUORESCENT OIL SIGNAL IN COMPRESSED GASES - Google Patents

Abstract

The invention relates to a technique for controlling the mass concentration of oil in compressed air at the outlet of compressor stations with a signal indicating that the permissible oil concentration is exceeded in the automatic control equipment of the compressor station. The fluorescent signaling device for oil in compressed gases includes a high-pressure chamber in the form of a flow cell for the analyzed gas equipped with sight glasses. The inner walls of the flow cell contain anti-reflective coating. The pulsed source of ultraviolet radiation includes a lamp, an ignition key and a master oscillator. The optical system for generating the excitation radiation of the analyzed gas includes a condenser lens, a translucent mirror and a filter that transmits radiation of the desired wavelength. The translucent mirror is located at an angle of 45 ° to the direction of radiation and provides the passage of excitation in the forward direction to the flow cell and its reflection in the direction of the second photodetector. The first photodetector detects the radiation of excitation (fluorescence) of the analyzed gas in the flow cell and contains a filter of a given spectral region and a photodetector of the registration channel. The second photodetector determines the intensity of the exciting radiation and includes a filter of a given spectral region and a photodetector. The third photodetector detects the intensity of the exciting radiation transmitted through the sight glasses of the cuvette and includes a filter of a given spectral region and a photodetector. The outputs of the first and third photodetector s

Description

Appointment

The utility model relates to a device for determining the concentration of oil in air and can be used for installation in high pressure air systems (VVD) to control the mass concentration of oil in compressed air at the output of compressor stations with a signal that the permissible oil concentration is exceeded in the compressor automatic control equipment station. The relevance of monitoring the maximum permissible concentration of oil in the air is associated with ensuring the safety of the VVD systems - with the exception of the explosion hazard when oil appears in pipelines.

State of the art

Known signaling device FLUORAT-411, developed by the company LUMEX LLC. The principle of operation of the detector is based on the luminescent method for detecting dissolved and emulsified oils and oil products in water.

The optical circuit of the detector consists of a luminescence (fluorescence) excitation channel, a reference channel, and a recording channel. This detector includes a xenon lamp - an excitation source, a lens with light filters, a beam splitter, a reference channel photodetector, a registration channel light filter, a PMT photodetector for a registration channel, an optical cable (optical fiber), a registration channel mirror, and a microprocessor. Functional diagram of the alarm is as follows. A pulsed light source under the control of a microprocessor generates light pulses, the intensity of which when passing through the optical circuit is controlled by a photodetector of the reference channel using the registration unit. Getting through the optical system and the ends of the fiber into the aqueous medium, these pulses excite fluorescence pulses, the magnitude of which is proportional to the concentration of dissolved emulsified oil products. The fluorescence pulses pass from the aqueous medium through the ends of the fiber in the opposite direction and are measured by a photodetector of the registration channel - PMT using the registration unit and processed by a microprocessor.

The microprocessor through the relay block controls the secondary devices (gate valves, valves, alarm) and transmits information to the display unit.

However, the above-described detector allows only monitoring the mass concentration of oil products in water, where the fluorescence value is large and high sensitivity and accuracy of the measurement method are not required.

A known device for determining oil mist in the air (patent US 4687327, CL G01N 21/59). This instrument is designed to measure the opacity of oil mist in air used in transmission systems with an oil suspension. The device is installed in a pipe crosspiece. Two opposing supports of the cross are used to pass an oil suspension past two opposite supports orthogonal to them, supporting an opacity measurement system. When using a bridge voltage source to power the amplifier, which forms the reference voltage on the reference diodes, the reference photocell receives the reference light flux from the light-emitting diode used for comparison. A second light emitting diode directs the light through the oil mist. The amount of light is measured by a second photocell, which records the absorption of light by the stream under study, and the signals from the outputs of two photocells are compared in a differential amplifier. At a certain value of the signal generated in the differential amplifier, a command is sent to the flow transmitting sensor to devices consuming air with an oil suspension.

In the described device, the control of the concentration of oil in the air stream is carried out not on the fluorescence method, but on measuring the degree of absorption of monochromatic radiation. This is because the device described in US Pat. No. 4,687,327 controls air with a metered content of oil mist or oil suspension. The control method based on measuring the degree of absorption of monochromatic radiation is justified by the fact that the level of oil concentration in the air is such that there are no requirements for high accuracy and sensitivity of the recording device.

The disadvantage of this device is the inability to control the concentration of oil in high pressure air at the outlet of the compressor station, the low sensitivity of the method based on measuring the degree of absorption of monochromatic radiation.

Of the known analogues of the invention, the closest prototype can be a device - detector according to patent US 3176623 class. F04B 43/00, designed

for controlling oil in compressed gases. In this detector device, the analysis of oil in gas is carried out directly in the high-pressure chamber. Outside the high-pressure chamber there is a source of ultraviolet radiation, a filter that transmits radiation of the required wavelength, and a condenser lens. Inside the chamber at an angle of 45 ° to the direction of the flow of excitation from the source of ultraviolet radiation, as well as to the gas stream from the supply fitting, a control plate is installed, coated with a non-reflective layer, for example, black matte varnish. Optoelectronic control of the high-pressure cavity in the chamber is provided by the use of viewing glazed devices. To receive radiation excited on the surface of the control plate (luminescence), a photodetector in the form of a photoelectronic device (PMT) is installed. The gas inlet and outlet fittings are connected to different sections of the compressor discharge pipe so that gas is circulated through the device.

In the event of a leak from the compressor compression chamber, the oil is deposited on the control plate and luminesces under the influence of exciting radiation. The output signal from the photomultiplier, proportional to the luminescence intensity of the control plate, is fed to an amplifier and a measuring device with an electrical contact device for triggering an alarm.

The disadvantage of such a detector device is that the oil is controlled not directly in the gas medium, but on the plate where the oil is deposited, which leads to a decrease in the sensitivity and accuracy of the oil control by the detector device. Reduces the accuracy of oil control and glare from the inside of the high pressure chamber.

In addition, this detector device has negative operational properties due to the fact that in the event of oil leakage from the compressor and its deposition on the control plate, further operation of the detector device is impossible without additional disassembly and removal of oil from the plate.

Another fundamental drawback is that during long-term operation of the detector device, the inevitable deposition of oil on the plate occurs, resulting in the formation of an erroneous signal about the excess of oil at a given time in the analyzed medium.

Utility Model Disclosure

The fluorescence signaling device for oil in compressed gases is a fluorescence analysis device - a fluorimeter, the operation of which is based on the physical principle of action - the glow (fluorescence) of oil vapor in the light flux.

It contains: a high-pressure chamber in the form of a flow cell for the analyzed gas, equipped with sight glasses, a pulsed source of ultraviolet radiation, an optical system for generating excitation radiation of the analyzed gas, including a condenser lens and a filter.

It also contains three photodetectors. The first photodetector is designed to detect the excited radiation and is located behind the flow cell on an axis perpendicular to the optical axis of the excitation radiation source. The second photodetector is placed up to the flow cell on an axis perpendicular to the optical axis of the excitation radiation source, and is used to record the intensity of the exciting radiation. The third photodetector is designed to detect exciting radiation passing through the sight glasses of the cuvette and is located behind the flow cell in relation to the radiation source on the same optical axis as the radiation source. The detector also contains two comparators and two indicator devices, and the optical system for generating excitation radiation includes a translucent mirror located at an angle of 45 ° to the direction of the radiation source, ensuring that the excitation radiation propagates in the forward direction and is reflected perpendicularly.

The inputs of the first comparator are connected to the first and second photodetectors, and its output is connected to the first indicator device.

The inputs of the second comparator are connected to the first and third photodetectors, and its output is connected to the second indicator device.

This technical solution avoids the dependence of the measurement result on the intensity of the excitation radiation and contamination of the inner surfaces of the protective glasses of the cuvette, and therefore ensures high sensitivity of the signaling device and accuracy of control.

In addition, the inner walls of the flow cell can contain an anti-reflective coating, which avoids spurious signals, and therefore increase the accuracy of the control.

In addition, an air flow limiter can be installed at the outlet of the flow cell. This will increase the life of the detector to preventive action.

List of graphic figures

Figure 1 shows a functional diagram of a fluorescent signaling device oil in compressed gases.

Figure 2 presents an example of a specific implementation of the fluorescent signaling device oil in compressed gases - FAM.

The numbers indicate:

1 - pulsed source of ultraviolet radiation

2 - optical system for generating the excitation radiation of the analyzed gas

3 - flow limiter

4 - high pressure chamber

5 - viewing windows

6 - third photodetector

7 - second photodetector

8 - the first photodetector

9 - second comparator

10 - second indicator device

11 - first comparator

12 - the first indicator device

13 - flash lamp

14 - lamp ignition key

15 - condenser

16 - light filter

17 - translucent mirror

18 - lens

19 - light filter

20 - photodetector

21 - amplifier

22 - optical lens

23 - filter

24 - photomultiplier tube (PMT)

25 - amplifier

26 - filter

27 - photodetector

28 - amplifier

Utility Model Implementation

The pulsed excitation source 1 is designed to generate light radiation, and the optical system 2 is used to isolate the ultraviolet part of the radiation spectrum and to transmit radiation in the forward direction to the high-pressure chamber, made in the form of a flow cell 4, and to reflect it in the perpendicular direction - to record the radiation intensity in the second photodetector 7.

One of the viewing windows 5 serves for the passage of light from the ultraviolet spectrum into the flow cell 4. In the presence of oil vapor in this flow cell, a fluorescent glow is formed. To detect it, the first photodetector 8 is used, which is located opposite the other viewing window of the flow cell, on an axis perpendicular to the optical axis of the excitation radiation source. The output of the first photodetector 8 is connected to the first input of the first comparator 11, the second input of which is connected to the output of the second photodetector 7. When the maximum allowable oil concentration in the analyzed gas is exceeded, the voltage at the first input of the comparator becomes equal or becomes greater than the voltage at the second input of the comparator and it operation with the issuance of a signal to the indicator device 12.

The third photodetector 6 is located behind the flow cell 4 with respect to the pulse excitation source 1 and monitors the contamination of the inner protective glasses of the cell 5 caused by the deposition of oil on them. The output of the third photodetector 6 is connected to the first input of the second comparator 9, the second input of which is connected to the output of the second photodetector 7. When the glass is dirty, the signal coming from the photodetector 6 to the first input of the comparator 9 is equal to or less than the signal coming from the photodetector 7 to the second input of the comparator 9. The comparator 9 is triggered with a signal to the indicator device 10 about the contamination of the pan glasses.

At the outlet of the flow cell, a flow limiter 3 can be installed, which sets the flow rate of the analyzed air through the cell and provides throttling of high pressure to atmospheric pressure.

An example of a specific implementation of the fluorescent signaling device oil in compressed gases is presented in figure 2.

The radiation source (flash lamp INP-5 / 45A) 13, the ignition key of the lamp 14 comprise a pulse excitation source. Capacitor 15, filter 16,

a translucent mirror 17 and a lens 18 constitute an optical system for generating excitation radiation of the analyzed gas.

Using the mirror 17, part of the excitation flux through the filter 19 enters the photodetector (KDF-105A photodiode) 20, which together with the amplifier 21 make up the second photodetector.

An optical lens 22, a filter 23, a photomultiplier tube (FEU-148) 24 and an amplifier 25 constitute the first photodetector.

The filter 26, a photodetector (KLF-105A photodiode) 27 and an amplifier 28 make up the third photodetector.

Comparator 11 is common for the first and second photodetectors, comparator 9 is for the second and third photodetectors

The analyzed air passes through a flow cell (high-pressure chamber) 4, equipped with protective glasses 5 and at the outlet of the cell the air is directed to the flow limiter 3 and then to the atmosphere.

An anti-reflective coating on the inner walls of the sight glasses can be applied, for example, the following: MNch.6 matte or Khch3.

The air flow limiter 3 can be made, for example, in the form of a device containing a gas channel in the form of a flat slotted spiral located between the inner and outer generatrices of cylindrical surfaces.

The operation of the alarm is as follows.

The light from the ultraviolet spectrum of the lamp 13 through the forming optical elements, falling into the flow cell, causes a fluorescent glow of the analyzed medium, which is emitted by the filter 23 and converted by the photoelectronic multiplier 24 into an electrical signal. This signal, the value of which is proportional to the flow of excitation and the concentration of oil in the air, after the formation of the photoelectronic multiplier 24 in the channel and amplification in the amplifier 25, is fed to the first input of the comparator 11. At the same time, a signal proportional to the excitation flow comes to the other input of the same comparator and not dependent on the concentration of oil. The operation of the comparator 11 with the issuance of a signal to the indicator device 10 occurs when the voltage at the first input is equal to or becomes greater than the voltage at its second input, i.e. when the oil concentration reaches the specified level.

Thus, with the adopted functional construction of the device, the level of response of the comparator 11 and the formation of the output signal does not depend on the magnitude of the excitation flux and is determined only by the ratio of the amplification factors of the amplifiers in the first and second photodetector devices.

All optical elements, with the exception of the lamp, condenser, mirror and photodetectors, are part of a cell under high pressure (up to 40 MPa). At the outlet of the cuvette there is a flow limiter 3, which sets the required air flow through the oil indicator. The hydraulic resistance of the air flow limiter is created due to the gas channel, made in the form of a flat slotted spiral located between the inner and outer generatrices of cylindrical surfaces.

Possible during the operation of the device contamination of the inner surfaces of the protective glasses of the cell, caused by the deposition of oil on them, can change the magnitude of the signal supplied to the first photodetector with the same excitation flux. To control this pollution, a signal generated by a third photodetector is used.

In the absence of contamination, the signal supplied to the first input of the comparator 9 from the third photodetector slightly exceeds the level of the signal fed to the second input of the comparator from the second photodetector. Pollution of protective glasses leads to a decrease in the signal generated by the third photodetector. If the voltages supplied to the inputs of the comparator 9 are equal, it is triggered and a signal is generated that indicates the contamination of the inner surface of the cell with the signal being sent to the indicator device 10.

Prototypes of oil signaling devices in compressed gases passed a successful experimental verification at the development stage (PIGN.413324.001). The data of the conducted experimental verification confirm the possibility of obtaining the above-mentioned technical result when using the utility model, which consists in creating a device that allows controlling the maximum permissible concentration of oil in compressed gases with high accuracy and sensitivity over the entire life cycle.

Thus, the claimed utility model provides high sensitivity and accuracy of control of oil in compressed air due to the implementation during operation of the device control the intensity of radiation of excitation and contamination of the inner surfaces of the protective glasses of the cell, caused by

the deposition of oil on them, the use of an air flow limiter that sets the amount of air flow through the flow cell, applying an anti-reflective coating to the inner surface of the cell. Using a fluorescent method for detecting oil vapor in compressed air at the outlet of compressor stations allows you to control the maximum oil concentration of about 80 mg / m ³ in a flow cell designed for pressure up to 40 MPa with the signal about exceeding the maximum permissible oil concentration in the compressor station automatic control equipment.

Claims (3)

1. A fluorescent detector of oil in compressed gases, comprising a high pressure chamber in the form of a flow cell for the analyzed gas, equipped with sight glasses, a pulsed ultraviolet radiation source, an optical system for generating excitation radiation of the analyzed gas, including a condenser lens and a filter, the first photodetector for the detected excited radiation located behind the flow cell on an axis perpendicular to the optical axis of the excitation radiation source, characterized the fact that it contains a second photodetector for exciting radiation intensity, a third photodetector for detecting exciting radiation transmitted through the sight glasses of the cuvette, as well as two comparators and two indicator devices, while the third photodetector is located behind one flow cell in relation to the radiation source on one the optical axis with the radiation source, the second photodetector is placed up to the flow cell on the axis perpendicular to the optical axis of the radiation source excitations, the outputs of the first and third photodetectors are connected to the first inputs of the first and second comparators, the second inputs of which are connected to the output of the second photodetector, and the outputs of the above comparators are connected to the corresponding indicator devices, and the optical system for generating excitation radiation includes a translucent mirror located at an angle of 45 ° to the direction of the radiation source, providing the passage of radiation of the excitation in the forward direction and reflection Its performance is perpendicular. 2. The fluorescent signaling device of oil in compressed gases according to claim 1, characterized in that the inner walls of the flow cell contain an anti-reflective coating. 3. The fluorescent signaling device of oil in compressed gases according to claim 1, characterized in that an air flow restrictor is installed at the outlet of the flow cell, containing a gas channel made in the form of a flat slotted spiral located between the inner and outer generatrices of cylindrical surfaces.