CN111734715A

CN111734715A - Device and method for monitoring (detecting) pollution degree of hydraulic oil particles sampled from drain valve

Info

Publication number: CN111734715A
Application number: CN202010596609.5A
Authority: CN
Inventors: 唐颖达; 刘尧
Original assignee: Suzhou Meifului New Material Technology Co ltd
Current assignee: Suzhou Meifului New Material Technology Co ltd
Priority date: 2020-06-28
Filing date: 2020-06-28
Publication date: 2020-10-02

Abstract

The invention discloses a device and a method for monitoring (detecting) the pollution degree of hydraulic oil particles sampled from a drain valve, and belongs to the technical field of monitoring (detecting) of hydraulic oil. The oil filling device comprises a circulating loop and a monitoring (detecting) loop, wherein the circulating loop comprises a one-way valve and a hydraulic pump for providing power, one end of the one-way valve is connected with one end of a first filter, the other end of the one-way valve is connected with an oil suction port of the hydraulic pump, the one-way valve cannot be reversely mounted, and an oil outlet of the hydraulic pump is connected with an oil filling filter in an oil tank through a third pipe fitting; the monitoring (detecting) loop comprises a pollution degree monitoring (detecting) instrument which is connected on the circulating loop in parallel. Through setting up circulation circuit, can make the interior hydraulic fluid flow of pipeline before the check valve be in abundant turbulent state to all fully mix the pollutant that deposits bottom the oil tank or the oil tank bottom near the flowing back valve is all abundant, can obtain the particle pollution degree liquid sample that represents the oil tank and even whole hydraulic system in flowing back valve department.

Description

Device and method for monitoring (detecting) pollution degree of hydraulic oil particles sampled from drain valve

Technical Field

The invention belongs to the technical field of hydraulic oil monitoring (detection), and particularly relates to a hydraulic oil particle pollution degree monitoring (detection) device for sampling from a drain valve.

Background

In hydraulic systems, power is transmitted and controlled by means of hydraulic oil in a closed circuit. The hydraulic oil is a lubricant and a power transmission medium. The presence of solid particulate contaminants in hydraulic fluids not only hinders their lubricating properties, but also can lead to wear and even failure of components. The degree of contamination of the hydraulic oil with solid particles is closely related to the performance of the hydraulic system, such as reliability and durability, and therefore should be controlled within the allowable range of the hydraulic system. However, the precondition is that the hydraulic oil must be monitored (detected) in real time or periodically.

In the hydraulic oil monitoring (detection), how to extract or collect a liquid sample (hereinafter, referred to as sampling) is a key link of the hydraulic oil monitoring (detection) technology, although it is proposed in GB/T17489-1998 "analyzing the hydraulic particle contamination by extracting a liquid sample from a pipeline of a working system": the "best method is to extract a liquid sample from one of the main lines of the hydraulic system being operated", but there are indeed many difficulties in practical operation.

Some existing hydraulic systems are not designed with a sampling valve, and therefore cannot sample in their main lines; even if the design is equipped with a sampling valve, sampling in hydraulic lines working at pressures above 5MPa is dangerous, especially sampling from high pressure lines, such as injection risks, hose whip risks, etc., and moreover there are ultra-high pressure hydraulic systems above 100 MPa; a more realistic problem is that the working hydraulic machine and its hydraulic system (including the tank) are often inaccessible. Taking a hydraulic system of a hydraulic machine as an example, according to the regulations of GB 28241-2012' technical requirements for safety of hydraulic machines, except that protective devices are not suitable to be installed on the hydraulic machines such as end sockets and ship plate forming, other hydraulic machines are mostly designed and installed with fixed closed protective devices and/or photoelectric protective devices, and the like, so as to prevent personnel from entering a dangerous area. Once personnel, including sampling and analysis personnel, enter the hazardous area, the hydraulic machine may be alerted and shut down urgently. Although the alternative sampling method specified in GB/T17489-1998 also exists: "extraction of a fluid sample from a tank of a hydraulic system in operation", and in GB/T37162.1-2018 "monitoring of the degree of contamination of hydraulic transmission fluid particles part 1: the procedure for suction sampling and analysis from tanks, as defined in the general rules, presents the same problem of being difficult to operate and even impossible to implement.

Even in a state where the hydraulic oil in the oil tank flows, since the oil tank itself has a function of precipitating heavy contaminants due to its structure, it is impossible to uniformly disperse the particulate contaminants throughout the oil tank. Specified in GB/T37162.1-2018: before sampling from a static container, the container is shaken sufficiently to mix the liquid in the container evenly. For the fuel tank, the so-called "sloshing method" is not operable. At this time, the hydraulic oil is not in a turbulent state, so that the particulate pollutants cannot be uniformly dispersed in the whole hydraulic oil, and the monitoring (detecting) result of the pollutant monitoring (detecting) instrument is not accurate and real enough.

Disclosure of Invention

1. Problems to be solved

In order to solve the problem that the hydraulic oil at a sampling point is directly sucked and sampled from an oil tank in the existing monitoring (detecting) device, and granular pollutants are not uniformly dispersed in the whole hydraulic oil, so that the monitoring (detecting) result of a pollutant monitoring (detecting) instrument is not accurate and real enough, the disclosure provides a monitoring (detecting) device and a method for monitoring the particle pollution degree of the hydraulic oil, wherein the hydraulic oil in a pipeline before a one-way valve can flow and is in a sufficient turbulent state by arranging a circulating loop, so that pollutants precipitated at the bottom of the oil tank or the bottom of the oil tank near the drainage valve are fully and uniformly mixed, a particle pollution degree liquid sample of a meter oil tank and even the whole hydraulic system can be obtained at the drainage valve, and then the pollution degree monitoring (detecting) instrument is used for monitoring (detecting) to ensure the accuracy and the reality of the pollution degree monitoring (detecting) result, the misjudgment is not easy to be caused.

2. Technical scheme

In order to solve the problems, the technical scheme adopted by the invention is as follows:

the invention provides a monitoring (detecting) method for the pollution degree of hydraulic oil particles sampled from a drain valve, which comprises the following steps:

sampling: acquiring hydraulic oil to be monitored (detected) from a drain valve on an oil tank;

and (3) circulation: the hydraulic oil is introduced into a circulation loop communicated with the drain valve, and a servo motor drives a hydraulic pump to enable the hydraulic oil to flow in the circulation loop to form a turbulent flow state;

monitoring (detecting) and detecting: and monitoring (detecting) the pollution degree of the hydraulic oil at a specified position on the circulating loop by a pollution degree monitoring (detecting) instrument connected in parallel on the circulating loop.

In some embodiments, a filtering step is further included between the circulating step and the monitoring (detecting) step, wherein the filtering step filters the hydraulic oil through a filter connected in series to the circulation circuit.

In some embodiments, the sampling step further comprises: and operating the hydraulic oil in the oil tank in a hydraulic system for at least a second time threshold, and then sampling from a drain valve on the oil tank.

In some embodiments, the cycling step;

(1) controlling the servo motor to operate the hydraulic pump at a flow rate below a first threshold for a first time threshold; wherein the first threshold flow rate is lower than the turbulent flow rate in the circulation loop;

(2) controlling the servo motor to operate the hydraulic pump at a second time threshold above a second threshold flow rate; wherein the second threshold flow rate is greater than the turbulent flow rate in the circulation loop.

In some embodiments, the filtering step comprises: and monitoring the pressure difference of the hydraulic oil in the filters through a pressure gauge, and when the pressure difference value of one or two filters exceeds a threshold value and does not reach signaling pressure drop, continuing to perform the step of circulating filtration.

In some embodiments, the contamination level monitoring (detecting) instrument monitors (detects) the contamination level of the hydraulic oil by using an automatic particle counting method.

The second aspect of the present invention provides a hydraulic oil particle contamination level monitoring (detecting) apparatus for sampling from a drain valve, comprising: the circulating loop comprises a one-way valve and a hydraulic pump for providing power, one end of the one-way valve is communicated with a liquid discharge valve on the oil tank through a first pipe fitting, the other end of the one-way valve is communicated with an oil inlet of the hydraulic pump, and an oil outlet of the hydraulic pump is connected with an oil injection filter in the oil tank; and

and the monitoring (detecting) loop comprises a pollution degree monitoring (detecting) instrument which is connected in parallel on the circulating loop and is used for monitoring (detecting) the pollution degree of the hydraulic oil at a specified position on the circulating loop. Through setting up circulation circuit, can make the interior hydraulic pressure fluid flow of pipeline before the check valve be in abundant turbulent state to all the intensive mixing is even with the pollutant that oil tank bottom or the near oil tank bottom of flowing back valve precipitated, can acquire representative liquid appearance in flowing back valve department, monitors (detects) through the contamination level monitoring instrument again, improves the accuracy of contamination level monitoring (detection) testing result, is difficult for causing the erroneous judgement.

In some embodiments, the monitoring circuit further comprises a first stop valve and a third stop valve, the oil inlet of the contamination level monitoring (detecting) device is connected to the first pipe via the first stop valve, and the oil outlet of the contamination level monitoring (detecting) device is communicated to the third pipe via the third stop valve. Through setting up first stop valve and third stop valve, when hydraulic fluid flows when mixing in the circulation circuit, can prevent not yet to reach the fluid entering contamination level monitoring (detection) instrument of turbulent state, guarantee to monitor (detect) that the testing result is true, accurate.

In some embodiments, the first pipe is provided with a second stop valve, the second stop valve is positioned at one side close to the one-way valve, and the first pipe is communicated with the drain valve through a quick-change connector with a double one-way valve. The quick-change connector with the double one-way valves is arranged, so that a pipeline close to one side of the liquid discharge valve can be disconnected after the test is finished, an oil inlet of the circulating pipeline does not receive hydraulic oil in the oil tank any more, and the discharge of the hydraulic oil is reduced to a certain extent; when the device is not used for monitoring (detecting), two ends of the quick-change connector 3 are disconnected, so that external pollutants can be prevented from entering a loop.

In some embodiments, the circulation circuit further comprises a second pipe and a third pipe, and the other end of the one-way valve is communicated with the oil inlet of the hydraulic pump through the second pipe; an oil outlet of the hydraulic pump is connected with an oil filling filter in the oil tank through a third pipe fitting, wherein a first filter is arranged on the second pipe fitting.

3. Advantageous effects

One or more technical solutions in the present application have at least one or more of the following technical effects:

(1) according to the invention, by arranging the circulating loop, hydraulic oil in the loop before the one-way valve can flow and is in a sufficient turbulent state, so that pollutants precipitated at the bottom of the oil tank or the bottom of the oil tank near the drain valve are fully and uniformly mixed, a representative liquid sample can be obtained at the drain valve, and then the pollution degree monitoring (detecting) instrument monitors (detects) the pollutants, so that the accuracy of the pollution degree monitoring (detecting) result is ensured, and misjudgment is not easily caused;

(2) by arranging the first stop valve and the third stop valve, when hydraulic oil in the circulation loop flows and is mixed, the oil which does not reach a turbulent flow state can be prevented from entering a pollution degree monitoring (detecting) instrument, so that the real and accurate monitoring (detecting) result is influenced;

(3) the quick-change connector with the double check valves is arranged, so that a pipeline close to one side of the drain valve can be disconnected after the test is finished, an oil inlet of the circulating pipeline does not receive hydraulic oil in an oil tank any more, and the outward discharge of the hydraulic oil is reduced to a certain extent; when the device is not monitored (detected), two ends of the quick-change connector 3 are disconnected, so that external pollutants can be prevented from entering a loop;

(4) by arranging the filter, the hydraulic oil can be filtered by using a filter program, and at least the part of the hydraulic oil which is generally most seriously polluted at the bottom of the oil tank can be filtered, so that a test instrument is effectively protected, and misjudgment caused by taking the hydraulic oil which is most seriously polluted as a liquid sample is avoided;

(5) the built-in pump mounting planes of the hydraulic pump and the pollution degree measuring instrument are at the same height as the oil tank mounting plane, so that the oil pumping ports of the built-in pumps of the hydraulic pump and the pollution degree measuring instrument always keep positive gauge pressure, and the factor that the monitoring (detection) generates errors due to negative pressure (vacuum) generated by general suction analysis is eliminated;

(6) the method provided by the invention conforms to the national standard, has specific operation rules and strong specific operation guidance, can be uniformly adopted by technical personnel in the field, is easy to popularize, realizes the uniformity of monitoring (detection) analysis schemes, and avoids the problems that in reality, people adopt different schemes to monitor (detection) different results, do not mutually recognize and repeatedly monitor (detect). The efficiency of links such as industry work exchange, trade is greatly improved.

Drawings

FIG. 1 is a schematic diagram of a conventional fuel tank sampling;

FIG. 2 is a schematic diagram of a prior art pumping sampling of a fuel tank;

fig. 3 is a schematic structural diagram of a hydraulic oil particle contamination level monitoring (detecting) apparatus according to an embodiment of the present invention;

fig. 4 is a flow chart of a method for monitoring (detecting) the contamination level of hydraulic oil particles sampled from a drain valve according to an embodiment of the present invention.

In the figure:

a1, low pressure source; a2, a fuel tank A; a3, sampling bottle; a4, flexible tube; a5, sampler; a6, a cover body;

b1, oil tank B; b2, a measuring instrument;

100. a circulation loop; 200. monitoring (detecting) the loop;

1. an oil tank; 2. a drain valve; 3. a quick-change connector with a double one-way valve; 4. a one-way valve; 5. a first shut-off valve; 6. a second stop valve; 7. a first filter; 8. a hydraulic pump; 9. a contamination level monitoring (detecting) instrument; 10. a servo motor; 11. a second filter; 12. a bypass check valve; 13. a pressure gauge switch; 14. a pressure gauge; 15. a third stop valve; 16. a hose; 17. Oil filter; 20. a first pipe member; 21. a second pipe member; 22. a third pipe member; 23. a fourth pipe member; 24. and a fifth pipe fitting.

Detailed Description

To make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some, but not all, embodiments of the present application. Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The invention is further described with reference to specific examples.

Summary of the application

Some existing hydraulic systems are not designed with a sampling valve, and therefore cannot sample in their main lines; even if the design is equipped with a sampling valve, sampling in hydraulic lines working at pressures above 5MPa is dangerous, especially sampling from high pressure lines, such as injection risks, hose whip risks, etc., and moreover there are ultra-high pressure hydraulic systems above 100 MPa; a more realistic problem is that the working hydraulic machine and its hydraulic system (including the tank) are often inaccessible. Taking a hydraulic system of a hydraulic machine as an example, according to the regulations of GB 28241-2012' technical requirements for safety of hydraulic machines, except that protective devices are not suitable to be installed on the hydraulic machines such as end sockets and ship plate forming, other hydraulic machines are mostly designed and installed with fixed closed protective devices and/or photoelectric protective devices, and the like, so as to prevent personnel from entering a dangerous area. Once personnel, including sampling and analysis personnel, enter the hazardous area, the hydraulic machine may be alerted and shut down urgently. Although the alternative sampling method specified in GB/T17489-1998 also exists: "extraction of a fluid sample from a tank of a hydraulic system in operation", and "monitoring (detection) of the degree of contamination of hydraulic transmission fluid particles" in GB/T37162.1-2018 section 1: the procedure for suction sampling and analysis from tanks, as defined in the general rules, presents the same problem of being difficult to operate and even impossible to implement.

For example, the YB/T4629-2017 "hydraulic oil change guide for metallurgical equipment L-HM hydraulic oil" also specifies: "4 samples 4.1 for the working system, as the case may be: c) sampling at a sampling point of the oil tank. "but there is no standard in its normative citation standard for sampling, and sampling is tentatively in accordance with GB/T17489-1998. For another example, in part 7 of the GJB 380.7A-2015 aviation operating fluid contamination test: the method of collecting a liquid sample in a liquid tank is specified in "method of collecting a liquid sample in a liquid tank", and there is no provision that the liquid tank must be operating. Therefore, the specification of the standard is more favorable for practical operation.

In addition, due to the fact that the sampling method and the program in the oil tank are not uniform and inconsistent, the monitoring (detecting) result cannot be confirmed by both the first party and the second party or authenticated by a third party, a large amount of manpower and material resources are wasted, the manufacturing cost of the product is increased, and the product cannot be delivered and used on schedule. The hydraulic elements and the system are cleaned and assembled again after the liquid samples are fed for many times, the hydraulic system is flushed for a very long time or repeatedly, and even new hydraulic oil is replaced, and the situation happens more than once in the previous operation. Therefore, according to the relevant standard sampling method and procedure, a representative liquid sample is extracted, so that the monitoring (detecting) result is accurate and real, and the method has very important practical application value.

According to the regulations of GB/T3766-2015, general rules and safety requirements for hydraulic transmission systems and their components, the tanks should have filling points (ports) and drains (drain valves). In GB/T17489-1998: "4.2 sample from tank 4.2.2 sample liquid is taken from a central region where the oil is flowing and leaving a quiescent zone due to corners or baffles. In section 4.2.3, as shown in fig. 1, an opening of the tank body above the liquid level in the oil tank Aa2 is selected, a sampler can extend into the opening, one end of the sampler is installed in the oil tank Aa2 through a flexible pipe a4, and a welding plug is arranged on the sampler; the sampling bottle a3 is covered with a cover body a6, the cover body a6 is a special cover for adapting to the sampled oil, and the cover body a6 is provided with a low-pressure source a 1. The distance h/2 was found to determine that the sampling point was set below the h/2 liquid level depth.

GB/T37162.1-2018 states that: the "6.3 off-line sample 6.3.7 is not suitable for sampling from the drain port. 6.6 suction analysis from a tank or container 6.6.1 should be taken from the point where the liquid flows. "there are four (main line, online, offline and aspiration) modes of sampling and analyzing liquid samples specified in this standard, with the aspiration analysis mode of operation being shown in FIG. 2. In appendix A (data appendix) of GB/T37162.1-2018: as shown in fig. 2, the measuring instrument b2 for suction analysis is mainly used for liquid analysis in a non-pressure container, for example: oil drum Bb1 or a system oil tank. In accordance with an interpretation of this standard, or should be expressed as: "suction analysis using a contamination level monitoring (detecting) device is mainly used for analysis of a liquid in a non-pressure container, for example: oil drum or system oil tank ". Since the "use of a contamination level monitoring (detection) device" is the main difference between the "aspiration analysis" and the "off-line analysis" specified by the standard. It has thus been determined that the sampling from the tank specified in GB/T17489-1998 is for "off-line analysis", but the sampling method recommended is also "pumping".

Both of the above two standards require that hydraulic oil in the oil tank is flowing during sampling, i.e. the hydraulic system and its oil tank are working; and requires that an opening in the tank head must be opened to allow the flexible tube and/or the probe to extend into the hydraulic fluid in the tank. However, in GB/T37162.1-2018, there is a clear problem with pumping at the surface of the liquid as shown in FIG. 2, rather than pumping at a depth below the surface. The sampling method prescribed or recommended by both standards is aspiration, except that in GB/T37162.1-2018, aspiration is recommended by a pump built in the contamination level monitoring (detecting) device.

Based on the comparison of the differences between the GB/T17489-1998 and the GB/T37162.1-2018 standards, the following questionable problems exist through further analysis:

1) even in a state where the hydraulic oil in the oil tank flows, since the oil tank itself has a function of precipitating heavy contaminants due to its structure, it is impossible to uniformly distribute particulate contaminants throughout the oil tank. Specified in GB/T37162.1-2018: before sampling from a static container, the container is shaken sufficiently to mix the liquid in the container evenly. For the fuel tank, the so-called "sloshing method" is not operable.

2) GB/T3766-2015 does not stipulate that a sampling port must be arranged on a top cover of a fuel tank. If the tank roof is not provided with a sampling opening in accordance with the GB/T17489-1998 specification, the most likely opening is the mounting hole of the air cleaner, i.e. the oil filling opening. Opening the oil filling port can cause external pollutants to enter the oil tank, especially a mounting hole of an air filter without a mounting flange; moreover, the mounting holes of the air filter are usually arranged at the corners of the tank roof, and the opening position does not meet the requirement of the 4.2.2 (see above) in GB/T17489-1998.

3) In GB/T17489-1998: "A reference mark is placed on the probe to indicate the tank level at the point of penetration. "is not necessarily feasible. One of the problems is how to see this reference mark at the filling opening, and the other is that the probe is connected to the flexible pipe and requires hydraulic oil to flow, and the probe and its mark may also change with time.

4) As described in GB/T37162.1-2018 annex a (data-bearing annex), the pump analysis approach requires the transport of a liquid sample from a container to a sensor (for example: by an internal pump) which is a source of error. If a pump is required to lift the liquid into the instrument, a negative pressure (vacuum) is created, drawing air from the liquid or from the tubing connection, and air bubbles in the analyzed liquid will affect the monitoring (detection) of the instrument and cause errors. If the pump is used upstream of the sensor, additional errors may be introduced due to the additional particles that may be generated during operation of the pump, resulting in less representative test data.

5) In GB/T17489-1998 the 4.2.8 bars "Note 1" indicate: "when a program to disseminate particulate contaminants has been determined for a particular system, the program should be maintained for all similar systems. "Note that" from this bar "it can be stated that the procedure" disperse the particulate contamination as evenly as possible throughout the tank "is not specified in GB/T17489-1998, and therefore there is considerable uncertainty in both sampling and analysis. It is believed in GB/T17489-1998 that the hydraulic fluid flowing in the tank favours "even distribution" of particulate contaminants. However, according to the design requirements of the oil tank specified in GB/T3766-2015: "it is desirable to circulate the hydraulic oil in the tank at a low rate to allow for the release of entrained gases and the precipitation of heavy contaminants". In a tank in actual use, the flow of hydraulic oil is contrary to the expectations of the GB/T17489-1998 standard. Since the flow of the hydraulic fluid in the tank does not act to "spread the particulate contamination as evenly as possible throughout the tank", it is not necessary to sample the hydraulic system and its tank while it is operating. Moreover, the sampling method and procedure from the tank, as defined by the above two standards, are difficult to operate.

Furthermore, according to practical experience, the following is specified in GJB 380.7A-2015: "4.2 sample points set sample points are set as required: a) when only the liquid injection port is arranged on the liquid tank, sampling is carried out at the liquid injection port, and b) when the liquid tank is provided with both the liquid injection port and the liquid discharge valve, sampling is carried out at the liquid discharge valve; d) the sampling position in the special liquid tank is determined by designers, and the position of the sampling point can represent the real pollution state of the working liquid in the liquid tank. "is easier to handle. However, sampling from the drain valve port is not recommended in GB/T37162.1-2018, which is inconsistent with the regulations in GJB 380.7A-2015, which is also a standard inconsistency problem that is currently urgently addressed.

Example 1

Embodiments of the present disclosure provide a hydraulic oil particle contamination level monitoring (detection) apparatus to solve or at least partially solve the above problems. Some example embodiments will now be described with reference to fig. 1. Note that in the following description, it is possible to use "hydraulic oil" as a sample to be monitored (detected). The scope of the present disclosure is not so limited and any monitoring (detection) device capable of employing the teachings herein is within the scope of the present disclosure.

Embodiments of the present disclosure provide a hydraulic oil particle contamination level monitoring (detection) device sampled from a drain valve to address, or at least partially address, the above-mentioned problems. Some example embodiments will now be described with reference to fig. 1. Note that in the following description, it is possible to use "hydraulic oil" as the sample to be monitored (detected). The scope of the present disclosure is not so limited and any monitoring (detection) device capable of employing the herein described is within the scope of the present disclosure.

As shown in fig. 1, in general, a hydraulic oil particle contamination level monitoring (detecting) apparatus according to an embodiment of the present disclosure includes a circulation circuit 100 and a monitoring (detecting) circuit 200.

The circulation circuit 100 includes a check valve 4 and a hydraulic pump 8 for power, the hydraulic pump 8 being driven by a servo motor 10. One end of the check valve 4 is communicated with the drain valve 2 on the oil tank 1 through a first pipe fitting 20, the other end of the check valve is communicated with an oil inlet of the hydraulic pump 8 through a second pipe fitting 21, and an oil outlet of the hydraulic pump 8 is connected with an oil filling filter 17 in the oil tank 1 through a third pipe fitting 22. Preferably, the third pipe member 22 is connected to the filler filter 17 in the oil tank 1 through the hose 16. In a possible embodiment, a dedicated air cleaner with a hard tube is used instead of the hard tube under the filler filter 17 and the hose 16, so that the hard tube can be inserted below the lowest liquid level in the tank, and a diffuser or a defoamer can be added to the end of the hard tube.

The monitoring (detecting) loop 200 comprises a pollution degree monitoring (detecting) instrument 9, and the pollution degree monitoring (detecting) instrument 9 is connected in parallel to the circulation loop 100 and is used for monitoring (detecting) the pollution degree of the hydraulic oil at a specified position on the circulation loop 100. Through setting up circulation circuit 100, can make the interior hydraulic fluid flow of pipeline before check valve 4 be in abundant turbulent state to the pollutant that deposits bottom the oil tank or near the oil tank bottom of flowing back valve 2 is all intensive mixing, can obtain representative liquid sample in flowing back valve 2 department, and rethread pollution degree monitoring (detection) instrument 9 monitors (detects), improves the accuracy of pollution degree monitoring (detection) survey result, is difficult for causing the erroneous judgement.

In some embodiments, the monitoring circuit 200 further comprises a first stop valve 5 and a third stop valve 15, the oil inlet of the contamination level monitoring instrument 9 is connected in series with the first pipe 20 via the first stop valve 5, and a section of hard pipe connected to the first stop valve 5 is connected in parallel to the hard pipe between the quick-change connector with double check valve 3 and the check valve 4, where the connection (sampling point) of the hard pipe to the first pipe 20 conforms to GB/T17489-1998. Further, the pipe diameter of the section of the hard pipe connected with the first stop valve 5 is d/4-d/3 of the pipe diameter of the first pipe between the quick-change connector 3 with the double one-way valve and the one-way valve 4, and the inner diameter of the section of the hard pipe connected with the first stop valve 5 is within the range of phi 1.2 mm-phi 5.0 mm. An oil outlet of the pollution degree monitoring (detecting) instrument 9 is connected with one end of a third stop valve 15, and the other end of the third stop valve 15 is connected to a section of hard pipe in front of a hose 16. The pollution degree monitoring (detecting) instrument 9 has a suction function for a built-in pump, and hydraulic oil sucked from a sampling point is discharged back to the oil tank 1 through a hose 16 and an oil injector 17 on the oil tank after particle counting is carried out by the pollution degree monitoring (detecting) instrument 9. In the present example, by providing the first stop valve 5 and the third stop valve 15, when the hydraulic oil in the circulation loop 100 flows and mixes, the oil that has not reached the turbulent flow state can be prevented from entering the pollution degree monitoring (detecting) instrument, and the real and accurate monitoring (detecting) result can be ensured. It should be noted that the first stop valve 5, the third stop valve 15 and the second stop valve 6 may be manual stop valves or electromagnetic valves, in this embodiment, manual stop valves are selected, and the manual stop valves have switch indication and signaling.

In some embodiments, the first tubular element 20 is provided with a second stop valve 6, the second stop valve 6 being located on the side close to the non-return valve 4, and the first tubular element 20 being in communication with said drain valve 2 through a quick-change coupling 3 with a double non-return valve. The front end of a quick-change connector 3 with a double one-way valve is connected with a drain valve 2 through a section of hose, the inner diameter of the hose is adapted to a connecting pipe of the drain valve 2 on an oil tank, and the hose and the connecting pipe of the drain valve 2 are locked by adopting a proper sealing measure and are prevented from falling off or leaking air. The quick-change connector 3 with the double check valves can disconnect a pipeline close to one side of the liquid discharge valve after the test is finished, so that an oil inlet of the circulating pipeline does not receive the hydraulic oil in the oil tank any more, and the discharge of the hydraulic oil is reduced to a certain extent; when the device is not used for monitoring (detecting), two ends of the quick-change connector 3 are disconnected, so that external pollutants can be prevented from entering a loop.

In some embodiments, the quick-change coupler 3 with the double check valve, the check valve 4, the stop valve 6 and the stop valve 6 are connected through hard pipes, that is, the first pipe fitting is a hard pipe, and the inner diameter phid of the hard pipe for connecting the quick-change coupler 3 with the double check valve and the check valve 4 is a parameter for calculating the reynolds number Re, and a user does not normally perform replacement, otherwise, the sampling point cannot be guaranteed to be in a sufficiently turbulent state.

In some embodiments, the second tube 21 is provided with a first filter 7; the third pipe member 22 is also provided with the second filter 11. In the present embodiment, the first filter 7 and the second filter 11 are both filters with a manual switching function, and when no filtering is required, they are both adjusted to a non-operation mode, in which both the first filter 7 and the second filter 11 are in an on state. When the pollutants in the oil tank are more, the pollutants are opened, so that a pollution degree monitoring (detecting) instrument can be effectively protected, the pollution degree monitoring (detecting) result is prevented from exceeding the maximum range, and misjudgment of subsequent measurement caused by taking the hydraulic oil with the heaviest pollution as a liquid sample is avoided. It should be noted that the filter with manual switching is an assembly in which the filter cartridge is new and generally thicker (> 65 μm) for each use. One end of the first filter 7 is connected with the one-way valve 4, and the other end of the first filter is connected with an oil inlet of the hydraulic pump 8, so that the first filter cannot be reversely mounted.

In some embodiments, the second filter 11 is connected in parallel with a bypass check valve 12. One end of the bypass one-way valve is communicated with one side, close to the oil inlet of the second filter 11, of the third pipe fitting through a fourth pipe fitting 23, and the other end of the bypass one-way valve is communicated with one side, close to the oil outlet of the second filter, of the third pipe fitting through a fifth pipe fitting 24. The bypass check valve 12 is connected in parallel with the second filter 11, and serves as a bypass valve of the second filter 11 and a safety valve of the entire monitoring (detecting) device.

In some embodiments, the fourth pipe 23 has an extension pipe 231, and the extension pipe 231 is provided with a pressure gauge switch 13 and a pressure gauge 14, and the pressure gauge 14 is used for monitoring (detecting) the pressure at the oil inlet of the hydraulic pump 8.

It should be noted that the pump analysis approach, as described in appendix A (data appendix) of GB/T37162.1-2018, requires the delivery of the liquid sample from the container to the sensor (e.g. by means of an internal pump), which is a source of error. If a pump is required to lift the fluid into the instrument, a negative pressure (vacuum) is created that draws air from the fluid or tubing connection, and air bubbles in the fluid being analyzed will affect the monitoring (detection) of the instrument and cause errors. If the pump is used upstream of the sensor, additional errors may be introduced due to the additional particles generated during operation of the pump, resulting in a less representative test result. In the preferred embodiment, the built-in pump mounting plane of the hydraulic pump and the pollution degree measuring instrument and the oil tank mounting plane are at the same height, so that the oil pumping ports of the built-in pumps of the hydraulic pump and the pollution degree measuring instrument are always kept at positive gauge pressure, and the error factor caused by the negative pressure (vacuum) generated by general suction analysis is eliminated.

Example 2

As shown in fig. 4, embodiments of the present disclosure provide a method for monitoring (detecting) contamination level of hydraulic oil particles sampled from a drain valve. It should be understood by those skilled in the art that the present embodiment is illustrated by the monitoring (detecting) device provided in embodiment 1, but not limited thereto. The method comprises the following steps:

s1: sampling: and acquiring hydraulic oil to be monitored (detected) in the oil tank from a drain valve on the oil tank. In particular, the embodiments

The monitoring (detecting) device in 1 is assembled and then sampling is carried out according to the following steps. See S11-S14 for details.

S11: cleaning the interfaces of the drain valve 2 and the quick-change connector 3 with the double one-way valve.

Specifically, the interface of the drain valve 2 and the interface of the double one-way valve quick-change connector 3 (one end) are cleaned by cleaning rag or cleaning liquid which does not fall off fibers, and the dustproof cap is opened. Also, the dust cap is opened by cleaning the exposed surface of the air cleaner and its surrounding hard tubing attached under the hose 16, where the air cleaner is an inherent device on the fuel tank and will not be described further.

S12: two ends of the quick-change connector 3 with the double one-way valve are connected through a hose, and then the quick-change connector 3 with the double one-way valve is communicated with the drainage valve 2.

S13: the drain valve 2 is opened to drain the waste hydraulic oil.

Specifically, the drain valve 2 is opened, the hydraulic oil between the drain valve 2 and the quick-change connector 3 with the double check valves is drained, the drain valve 2 is closed, and the drained hydraulic oil can only be used as waste oil and is treated according to the environmental protection requirement.

Optionally, the drain valve 2 is opened, and after a certain amount of hydraulic oil is extracted by using a clean and transparent sampling bottle, the drain valve 2 is closed. The pollution degree can be visually observed according to related standards such as NB/SH/T0599-2013L-HM hydraulic oil change index and the like, and the hydraulic oil in a sampling bottle can be measured by an 'automatic particle counter' specified in GB/T37163-2018 automatic particle counting method for measuring the pollution degree of liquid sample particles by adopting a shading principle in hydraulic transmission.

S14: the upper part of the air cleaner of the oil tank 1 is removed, and the hose 16 of the monitoring (detecting) device is connected with the oil filling filter 17, so that the connection between the whole structure of the monitoring (detecting) device and the oil tank 1 is completed. A section of hose with a quick-change connector 3 with a double-check valve is disassembled, and the corresponding end of the hydraulic oil particle pollution degree monitoring (detecting) device in the embodiment 1 is connected with the hose; the upper part of the air filter is detached, and the corresponding end of the 'hydraulic oil particle pollution degree monitoring (detecting) device' with the same upper part of the air filter is connected with the oil injection filter 17.

For safety reasons, the present embodiment is based mainly on the GJB 380.7A-2015 standard, and the drain valve sampling and analysis should be started immediately after the hydraulic system and its oil tank stop working. It should be noted that although the "oil drain valve sampling program" is defined in GJB380.7A-2015, it is difficult to operate consistently and obtain a representative liquid sample, which specifies that the working fluid should be agitated in an appropriate manner before sampling and that sampling should be performed with contaminants in a suspended state. However, if the oil tank is not operated for a long time, pollutants such as solid particles, gel, oil sludge (sediment or residue with the size less than 3 μm generated from oxidized mineral oil) and the like in the hydraulic oil are concentrated and precipitated at the bottom of the oil tank, and for the oil tank with larger oil tank volume, the uniform mixing of the hydraulic oil in the whole oil tank is difficult to finish only by a hydraulic oil particle pollution degree monitoring (measuring) device sampled from a drain valve.

Therefore, in some embodiments, the sampling step further comprises: and (3) enabling the hydraulic oil in the oil tank to normally operate at least for a second time threshold in the hydraulic system, and then sampling from a drain valve on the oil tank. Preferably, the sampled oil is also subject to "health and safety" requirements as set forth in the GB/T37162.1-2018 standard. It should be noted that sampling and analysis from a tank that has just been taken out of service is most certainly possible and most readily accepted and agreed upon by the parties, otherwise the sample does not represent a true contamination condition of the hydraulic system. The second time threshold in this embodiment is 24 h.

S2: and (3) circulation: and (3) switching on a power supply of the servo motor 10, starting the servo motor 10 and the hydraulic pump 8, introducing hydraulic oil into a circulating loop communicated with the drain valve, and driving the hydraulic pump by the servo motor to enable the hydraulic oil to flow in the circulating loop to form a turbulent flow state. When the filtering step is not performed, the first filter 7 and the second filter 11 with the manual switching function are switched to the through circuit, and the oil circulation is started.

Preferably, (1) the servo motor is controlled to operate the hydraulic pump at a flow rate below a first threshold for a first time threshold; wherein the first threshold flow rate is lower than the turbulent flow rate in the circulation loop; in this embodiment, the reynolds number Re of the first threshold flow is 2300, and the first time threshold is 10min, during which it is necessary to observe whether the circulation loop 200 is abnormal, and if so, the loop is shut down for inspection; if not, the next step is continued.

(2) Controlling the servo motor to operate the hydraulic pump at a second time threshold above a second threshold flow rate; wherein the second threshold flow rate is equal to or greater than the turbulent flow rate in the circulation loop. In this embodiment, the second time threshold is 30min, and the reynolds number Re of the second threshold flow is 4000. It should be noted that the turbulent flow rate in the circulation loop is related to the inner diameter phid of the first pipe body connected between the quick-change connector 3 with the double one-way valve and the one-way valve 4, and the inner diameter phid is different, and the turbulent flow rate in the circulation loop is also different. To ensure that the sampling point is sufficiently turbulent, the user is not typically left to replace the first tube 20. If one filter sends an alarm, all filters should be replaced by new filter elements.

S3: monitoring (detecting) and detecting: and the pollution degree of the hydraulic oil at a specified position on the circulating loop is monitored (detected) by a pollution degree monitoring (detecting) instrument 9 connected in parallel on the circulating loop. When the pressure difference of each filter is not changed obviously, the first stop valve 5 and the third stop valve 15 are opened, and the pollution degree monitoring (detecting) instrument 9 is started to monitor (detect). In some embodiments, the contamination level monitoring instrument monitors the hydraulic oil by automatic particle counting. The intended use and the desired accuracy of the data measured by the contamination level monitoring (detecting) device 9 here determine the chosen analytical manner and the precision of the monitoring (detecting) device required.

Confirmation of the monitoring (detection) result in this embodiment:

monitoring (detecting) the liquid sample until the monitoring (detecting) data of two continuous liquid samples meet one of the following conditions:

a) the monitoring (detecting) result is in the allowable range set by the manufacturer of the pollution monitoring (detecting) instrument;

b) if the result of the monitoring (detection) is the number of particles, the difference between the monitoring (detection) results of the two liquid samples is less than 10% on the minimum particle size of the monitored (detection);

c) the pollution degree grades specified by GB/T14039-2002 'code of hydraulic transmission oil solid particle pollution grade' or other standards are the same;

secondly, according to the standard regulation, the monitoring (detection) report is signed.

After the monitoring (detection) is finished, the closing states of the drain valve 2 and the stop valve are checked and confirmed, if the both are closed, the end part of the hard pipe below the hose 16 is drawn out, the dust cap is worn, and then the hard pipe is put into the device; the oil filter at the upper part and the lower part of the original air filter is assembled (recovered); disconnecting the quick-change connector 3 with the double one-way valve and collecting the quick-change connector into the device; then the hydraulic oil particle pollution degree monitoring (detecting) device is withdrawn from the safety protection area of the hydraulic machine; restoring the fixed closed protection device and/or the photoelectric protection device, etc. Furthermore, it is not recommended to use a hydraulic oil particle contamination level monitoring (detecting) device for long-term sampling and analysis of hydraulic oil in a tank, and to use the device as a bypass regeneration filter device.

It should be noted that the contamination level monitoring (detecting) device 9 can be selected according to the analysis method listed in table 1, and no other analysis method for sampling from the stop valve 6 is included in table 1.

TABLE 1 pollution degree monitoring (detecting) instrument suction analysis mode table

It should also be noted that sampling from the drain valve is not recommended in GB/T37162.1-2018, according to which standard the skilled person would not normally think of sampling at the drain valve, where there is a technical prejudice, and furthermore it is considered in GB/T17489-1998 that the hydraulic oil flowing in the tank favours "uniform distribution" of particulate contaminants, but due to the structure of the tank itself, it is impossible for the oil to achieve a turbulent flow of the oil in the tank, according to which the applicant, by creatively arranging a circulation circuit outside the tank, can cause the hydraulic oil in the line before the non-return valve to flow and be in a sufficiently turbulent flow, so that the contaminants deposited at the bottom of the tank or at the bottom of the tank in the vicinity of the drain valve are mixed sufficiently and uniformly, and a liquid sample representing the tank and hence the entire hydraulic system can be obtained at the drain valve, and then the pollution degree monitoring (detecting) instrument monitors (detects) to ensure the reality and accuracy of the pollution degree monitoring (detecting) data and avoid causing misjudgment.

In some embodiments, the circulating step and the monitoring (detecting) step further include an S4 filtering step, wherein the filtering step filters the hydraulic oil through a filter connected in series to the circulating loop. Here, the filter may be selected to be used or not used depending on the agreement between the monitoring (detecting) party and the monitored (detecting) party.

Before the filtration step, it is necessary to check the closed first, second and

third stop valves

5, 6, 15 and open the drain valve 2. Furthermore, all filter elements should be new and should correspond to the particle size [ μm (c) ] corresponding to the filter filtration ratio in the monitoring device. Specifically, when the filtering step is performed, the first filter 7 and the second filter 11 having the manual switching function are switched to the filter circuit, and the next operation is started.

In some embodiments, during filtration, the pressure differential of the hydraulic oil in the filters is monitored by a pressure gauge, and when the pressure differential of one or both of the filters exceeds a threshold value and no signaled pressure drop is achieved, the cyclical filtration step is continued for 30 min.

Furthermore, if the filtering is continued, it is found that the following operations are performed as agreed by the monitoring (detecting) party and the monitored (detecting) party, and the sampling and analyzing operations should be immediately stopped and the sampling and analyzing records should be made.

If the pollution degree monitoring (detecting) instrument 9 is started to monitor (detect) after the circulation filtration is continued for 30min, one or two transmitters start to alarm; it should be noted that the signaling device is an existing device on the filter, and is used for sending out an electric signal, an audible and visual alarm signal and the like when the filter is blocked.

Secondly, if the circulation filtering is continued but before 30min is reached, one or two signal transmitters start to alarm.

③ if the circulation filtering is continued for 30min, the pressure difference of one or two filters still increases obviously, but they do not reach signaling pressure drop.

It should be noted that, before the monitoring (detecting) step, because of the particularity of the oil tank sampling, the filtering step is preferably selected, so that the testing instrument can be effectively protected and the misjudgment can be avoided; if a certain filter sends an alarm in the filtering process, all filters should be replaced by new filter elements.

In some embodiments, the hydraulic fluid may be selectively filtered for 40min, and then the first filter 7 and the second filter 11 with manual switching function are switched to the through-circuit, and sampling and analysis are started, which can monitor (detect) the hydraulic fluid for a long time, but a special oil filling filter should be used, wherein the special oil filling filter means that the oil filling filter has an oil pipe passing through the bottom of the oil filling filter and is inserted below 300mm below the liquid level in the hydraulic fluid in the oil tank, so that the hard pipe below the hose 16 can be inserted below the lowest liquid level in the oil tank.

Finally, it is to be stressed that there are no practical methods and procedures available in the current standards to ensure the extraction of the liquid sample representing the real state of contamination of the hydraulic system and of the hydraulic oil in its tank, from the draining valve in the tank or in the tank. The monitoring (detecting) method for the pollution degree of hydraulic oil particles sampled from the drain valve conforms to the regulation of GJB 380.7A-2015 standard; also conforms to the 'principle of extracting oil liquid' specified by GB/T17489-1998 standard; and procedures and precautions for "obtaining representative samples" in compliance with the GB/T37162.1-2018 Standard, including compliance with the "off-line sampling" and "drawing from a tank or container".

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not represent the only embodiments.

It should also be noted that the terms "a," "an," "two," and the like in the description and claims of this application and in the above-described drawings are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included within the scope of the present invention.

Claims

1. A method for monitoring (detecting) the pollution degree of hydraulic oil particles sampled from a drain valve is characterized by comprising the following steps:

2. The method as claimed in claim 1, wherein a filtering step is further included between the circulating step and the monitoring step, wherein the filtering step filters the hydraulic oil through a filter connected in series to the circulation loop.

3. The method for monitoring (detecting) the contamination level of hydraulic oil particles sampled from a drain valve according to claim 1, wherein the sampling step further comprises: and operating the hydraulic oil in the oil tank in a hydraulic system for at least a second time threshold, and then sampling from a drain valve on the oil tank.

4. The method for monitoring (detecting) the contamination level of hydraulic oil particles sampled from a drain valve according to claim 2, wherein in the circulating step;

5. A method for monitoring (detecting) the contamination level of hydraulic oil particles sampled from a drain valve according to claim 4, characterized in that said filtering step comprises: and monitoring the pressure difference of the hydraulic oil in the filters through a pressure gauge, and when the pressure difference value of one or two filters exceeds a threshold value and does not reach signaling pressure drop, continuing to perform the step of circulating filtration.

6. The method as claimed in claim 1, wherein the contamination level monitor is an automatic particle counting method for monitoring contamination level of the hydraulic oil.

7. A hydraulic oil particle contamination level monitoring (detecting) device for sampling from a drain valve, comprising:

the circulating loop comprises a one-way valve and a hydraulic pump for providing power, one end of the one-way valve is communicated with a liquid discharge valve on the oil tank through a first pipe fitting, the other end of the one-way valve is communicated with an oil inlet of the hydraulic pump, and an oil outlet of the hydraulic pump is connected with an oil filling filter in the oil tank; and

and the monitoring (detecting) loop comprises a pollution degree monitoring (detecting) instrument which is connected in parallel on the circulating loop and is used for monitoring (detecting) the pollution degree of the hydraulic oil at a specified position on the circulating loop.

8. The hydraulic oil particulate contamination level monitoring device sampled from the drain valve of claim 7, wherein the monitoring circuit further comprises a first cut-off valve and a third cut-off valve, wherein the oil inlet of the contamination level monitoring device is connected to the first pipe via the first cut-off valve, and the oil outlet of the contamination level monitoring device is connected to the oil filter in the oil tank via the third cut-off valve.

9. The apparatus as claimed in claim 8, wherein the first pipe member is provided with a second stop valve, the second stop valve is located at a side close to the oil inlet of the check valve, and the first pipe member is connected to the drain valve through a quick-change connector having a double check valve.

10. The apparatus as claimed in claim 9, wherein the circulation loop further comprises a second pipe and a third pipe, and the other end of the check valve is connected to the oil inlet of the hydraulic pump through the second pipe; an oil outlet of the hydraulic pump is connected with an oil filling filter in the oil tank through a third pipe fitting, wherein the second pipe fitting is provided with a first filter.