Anti-back-surge control method for vacuum toilet system of rail vehicle and vacuum toilet system

Abstract

The application provides a blowback prevention control method for a vacuum excrement collecting system of a rail vehicle and a vacuum excrement collecting system suitable for the blowback prevention control method. Specifically, the blowback prevention control method comprises the following steps: firstly, before the rail vehicle runs, a control unit performs vacuum detection on the sealing state of an excrement inlet hose valve connected to an excrement transfer box inlet to obtain a detection result; if the detection result is qualified, the control unit controls the vacuum excrement collecting system to enter a standby state, and the rail vehicle is ready to run; secondly, during the running of the rail vehicle, the control unit monitors the closing state of each toilet discharge valve in real time and disables the corresponding fault toilet of the toilet discharge valve in an abnormal state to prevent blowback of the fault toilet, and the excrement in the toilet is transported to the excrement transfer box through a pipeline; finally, after the rail vehicle stops running, the control unit controls the abnormal pressure in the pipeline to be released to prevent blowback, and controls the excrement transfer box to be applied with positive pressure to empty the excrement.

Description

Technical Field

[0001] This application relates to the field of rail transit technology, and in particular to a method for preventing backflow control in a vacuum waste collection system for rail vehicles, as well as the vacuum waste collection system itself. Background Technology

[0002] High-speed trains and other rail vehicles are generally equipped with vacuum toilet systems to collect and temporarily store waste after passenger use. A typical vacuum toilet system operates as follows: after the toilet is emptied, the waste first enters a waste transfer tank for temporary storage. A vacuum generator then creates negative pressure to suck the waste into the main waste tank. Upon arrival at the station, positive pressure is applied to the waste transfer tank to empty the waste to ground facilities. This system involves multiple components, including the toilet, toilet drain valve, waste inlet hose valve, waste transfer tank, wastewater tank, vacuum generator, and control unit. All valves must work together to ensure proper operation.

[0003] However, in practical application, the vacuum toilet system of this technology has the following problems. On the one hand, the toilet drain valve may not close properly due to mechanical jamming or blockage by foreign objects, and the inlet hose valve may fail to seal due to ruptured or aged bladder. On the other hand, during positive pressure emptying of the waste transfer tank, or due to pipeline design reasons, abnormal positive pressure may exist inside the pipeline between the toilet drain valve and the inlet hose valve. When the toilet drain valve does not close properly and the inlet hose valve also fails to seal, waste will be backflowed from the waste transfer tank through the inlet hose valve and the toilet drain valve under positive pressure, severely affecting the sanitary environment of the toilet and the usability of vehicles. The relevant technology lacks real-time monitoring of the valve status and proactive handling mechanisms for abnormal positive pressure in the pipeline, making it difficult to effectively prevent such backflow failures.

[0004] Therefore, how to improve the anti-backflow capability of vacuum waste collection systems at the system level has become a technical problem that needs to be solved in this field. Summary of the Invention

[0005] In view of this, in order to solve at least one technical problem in related technologies and other aspects, this application proposes an anti-backflow control method for a vacuum sewage collection system for rail vehicles, comprising: First, before the rail vehicle starts running, the control unit performs a vacuum test on the sealing status of the inlet hose valve connected to the sewage transfer box inlet, obtains the test result, and if the test result is qualified, the control unit controls the vacuum sewage collection system to enter the standby state, and the rail vehicle is ready to run; Second, during the operation of the rail vehicle, the control unit monitors the closing status of the drain valve of each toilet in real time and disables the faulty toilet corresponding to the drain valve of the abnormal state, so as to prevent the faulty toilet from backflowing, and the sewage in the toilet is transported to the sewage transfer box through the pipeline; Finally, after the rail vehicle stops running, the control unit controls the release of abnormal pressure in the pipeline to prevent backflow, and controls the application of positive pressure to the sewage transfer box to empty the sewage.

[0006] According to an embodiment of this application, the sealing status of the inlet hose valve connected to the inlet of the waste transfer box is detected, including: First, the control unit controls the vacuum generator to perform a vacuuming operation on the waste transfer box until the vacuum switch installed on the waste transfer box outputs a vacuum establishment signal; Second, in response to the vacuum establishment signal, the control unit shuts off the vacuum generator and the inlet hose valve, and after a first preset time delay, controls the opening of the toilet drain valve, wherein the first preset time is 3 seconds; Finally, within a second preset time after the toilet drain valve is opened, if the vacuum establishment signal output by the vacuum switch disappears, the control unit determines that the inlet hose valve has a sealing failure and issues a fault command, and the vacuum waste collection system is unusable, wherein the second preset time is 2 seconds.

[0007] According to an embodiment of this application, real-time monitoring of the closing status of each toilet drain valve includes: detecting the closing position information of the toilet drain valve in real time by a position sensor installed on each toilet drain valve, and outputting an abnormal signal to the control unit if the toilet drain valve is not strictly closed.

[0008] According to an embodiment of this application, disabling a faulty toilet corresponding to an abnormal toilet drain valve includes: first, in response to an abnormal signal, the control unit closes the abnormal toilet drain valve; second, if the control unit receives an abnormal signal again, it controls the faulty toilet to repeatedly perform multiple flushing actions; finally, after a predetermined number of flushing actions, if the control unit still receives an abnormal signal, it determines that the abnormal toilet drain valve has malfunctioned, the control unit outputs a fault signal and isolates the faulty toilet.

[0009] According to an embodiment of this application, the isolation operation includes: the control unit prohibits the faulty toilet from performing flushing and sewage discharge actions, closes the drain valve of the abnormal toilet, and outputs a fault alarm signal.

[0010] According to an embodiment of this application, the control unit controls the release of abnormal pressure in the pipeline, including: in response to a positive pressure venting command issued by the control unit to the waste transfer tank, the wastewater drain valve of the wastewater tank is opened, so that the pipeline between the toilet drain valve and the inlet hose valve is connected to the atmosphere through the wastewater transfer tank, thereby releasing the abnormal positive pressure in the pipeline.

[0011] According to an embodiment of this application, applying positive pressure to the waste transfer box to empty the waste includes: after the abnormal positive pressure is released, the control unit opens the drain hose valve of the waste transfer box and applies positive pressure to the waste transfer box so that the waste in the waste transfer box is transferred to the waste tank.

[0012] According to an embodiment of this application, after the waste is drained, the wastewater discharge valve is controlled to close after a delay to ensure that the residual positive pressure in the pipeline is released.

[0013] According to an embodiment of this application, the aforementioned anti-backflow control method further includes: before vacuum detection, the control unit controls the wastewater discharge valve of the wastewater tank to open to release residual positive pressure and avoid residual positive pressure interfering with vacuum detection.

[0014] In another aspect of this application, a vacuum waste collection system for a rail vehicle is also disclosed, comprising a toilet, a wastewater tank, a waste transfer tank, a waste bin, a vacuum generator, and a control unit. The toilet is used to collect waste, and its outlet is equipped with a toilet drain valve to control waste discharge from the toilet into the pipeline. The wastewater tank is used to collect washing wastewater, and its outlet is equipped with a wastewater drain valve to control the discharge of wastewater from the tank and gas from the pipeline. The waste transfer tank is used to temporarily store waste, and its inlet and outlet are respectively equipped with a waste inlet hose valve and a waste outlet hose valve to control waste entering or exiting the waste transfer tank. The waste bin is used to store final waste. The vacuum generator is connected to the waste transfer tank and is used to generate vacuum and positive pressure. The control unit is arranged on the rail vehicle and is electrically connected to the toilet drain valve, waste inlet hose valve, wastewater drain valve, waste outlet hose valve, and vacuum generator, respectively. The control unit executes the aforementioned anti-backflow control method.

[0015] According to an embodiment of this application, the aforementioned vacuum waste collection system further includes a vacuum switch disposed on the waste transfer box. The vacuum switch is suitable for detecting the vacuum level inside the waste transfer box and outputting a vacuum status signal.

[0016] According to an embodiment of this application, the aforementioned vacuum toilet system further includes a position sensor disposed on the toilet drain valve, which is suitable for real-time detection of the mechanically closed state of the toilet drain valve and outputting a position signal.

[0017] According to an embodiment of this application, before the rail vehicle operates, the control unit performs a vacuum test on the sealing status of the sewage inlet hose valve. Only after passing the test is the vacuum toilet system allowed to enter standby mode. This prevents the rail vehicle from operating with a defective sewage inlet valve, reducing the risk of backflow from the source. During operation, the control unit monitors the closing status of each toilet's drain valve in real time. If an abnormal closing of a drain valve is detected, the corresponding faulty toilet is immediately disabled to prevent it from becoming an outlet for sewage backflow during subsequent use or when the vacuum toilet system is emptied. After the vehicle stops operating, the control unit first releases the abnormal pressure in the pipeline, and then applies positive pressure to the sewage transfer box to empty the sewage. This sequence ensures that even if the drain valve or sewage inlet valve is slightly not tightly closed, the sewage cannot be backflowed because there is no positive pressure in the pipeline. Through the coordination of the above three steps, the probability of backflow in the vacuum toilet system can be systematically reduced, improving the reliability of the rail vehicle toilet and passenger comfort. Attached Figure Description

[0018] Figure 1 This is a flowchart of an anti-backflow control method for a vacuum toilet system for rail vehicles, according to one embodiment of this application.

[0019] Figure 2 This is a schematic diagram of the structure of a vacuum waste collection system in one embodiment of this application.

[0020] In the accompanying drawings, the meanings of the reference numerals are as follows:

[0021] 1-First set of toilets;

[0022] 11-First drain valve;

[0023] 2-Second set of toilets;

[0024] 21-Second drain valve;

[0025] 3-Wastewater transfer tank;

[0026] 31 Wastewater discharge valve;

[0027] 32-Washing wastewater;

[0028] 33 - Overflow valve;

[0029] 4- Waste transfer box;

[0030] 41-Inlet hose valve;

[0031] 42 - Sewage hose valve;

[0032] 5-Sewage bin;

[0033] 6-Vacuum generator;

[0034] 61 - Vacuum hose valve;

[0035] 7-Positive pressure inlet. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0037] The endpoints and any values ​​of the ranges disclosed in this application are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this application.

[0038] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0039] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0040] It should be noted that, unless otherwise defined, the technical or scientific terms used in this application should have the ordinary meaning understood by a person with ordinary skill in the art to which this application pertains. Where the terms "first," "second," etc., are used throughout, they are used only to distinguish similar objects and should not be construed as indicating or implying their relative importance, order of precedence, or implicitly specifying the number of technical features indicated. It should be understood that the data in the descriptions of "first," "second," etc., can be interchanged where appropriate.

[0041] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0042] In the description of this application, it should be understood that the terms "longitudinal", "length", "circumferential", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the subsystem or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0043] Throughout the accompanying drawings, identical elements are represented by the same or similar reference numerals. Conventional structures or configurations will be omitted where they may cause confusion in understanding this application. Furthermore, the shapes, dimensions, and positional relationships of the components in the drawings do not reflect their actual size, scale, or actual positional relationships. Additionally, any reference symbols placed within parentheses in this application should not be construed as limiting the scope of this application.

[0044] Similarly, to simplify this application and aid in understanding one or more of the various disclosed aspects, in the above description of exemplary embodiments of this application, various features of this application are sometimes grouped together into a single embodiment, figure, or description thereof. The use of terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicates that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0045] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0046] In the process of developing this application, it was discovered that toilet backflow accidents are not caused by a single malfunction, but are the result of three adverse conditions existing simultaneously: the toilet drain valve not closing tightly, the inlet hose valve failing to seal, and abnormal positive pressure existing in the pipeline between the drain valve and the inlet valve. If only one aspect is improved, such as simply strengthening the sealing of the drain valve, it is still impossible to prevent backflow when the inlet valve is damaged.

[0047] Therefore, this application adopts a collaborative control strategy covering the entire operation process of rail vehicles: before the vehicle is put into operation, the sealing performance of the sewage hose valve is actively tested to ensure that its condition is qualified; during the operation, the mechanical closing status of the drain valve of each toilet is continuously monitored, and the corresponding toilet is immediately disabled once an abnormality is detected; before the emptying operation is performed after the operation stops, the abnormal pressure in the pipeline is released first to eliminate the power conditions for backflow.

[0048] Figure 1 This is a flowchart of an anti-backflow control method for a vacuum toilet system for rail vehicles, according to one embodiment of this application.

[0049] This application proposes a method for preventing backflow control in a vacuum toilet system for rail vehicles, such as... Figure 1 As shown, it includes the following steps S1 to S3.

[0050] Step S1: Before the rail vehicle starts running, the control unit performs a vacuum test on the sealing status of the valve of the sewage inlet hose connected to the sewage transfer box inlet. If the test result is qualified, the control unit controls the vacuum sewage collection system to enter the standby state, and the rail vehicle is ready to run.

[0051] Step S2: During the operation of the rail vehicle, the control unit monitors the closing status of each toilet's drain valve in real time and disables the faulty toilet corresponding to the abnormal state of the toilet's drain valve to prevent the faulty toilet from backflowing. The sewage in the toilet is transported to the sewage transfer box through the pipeline.

[0052] Step S3: After the rail vehicle stops running, the control unit controls the release of abnormal pressure in the pipeline to prevent backflow, and controls the application of positive pressure to the sewage transfer box to empty the sewage.

[0053] According to an embodiment of this application, before the rail vehicle operates, the control unit performs a vacuum test on the sealing status of the sewage inlet hose valve. Only after passing the test is the vacuum toilet system allowed to enter standby mode. This prevents the rail vehicle from operating with a defective sewage inlet valve, reducing the risk of backflow from the source. During operation, the control unit monitors the closing status of each toilet's drain valve in real time. If an abnormal closing of a drain valve is detected, the corresponding faulty toilet is immediately disabled to prevent it from becoming an outlet for sewage backflow during subsequent use or when the vacuum toilet system is emptied. After the vehicle stops operating, the control unit first releases the abnormal pressure in the pipeline, and then applies positive pressure to the sewage transfer box to empty the sewage. This sequence ensures that even if the drain valve or sewage inlet valve is slightly not tightly closed, the sewage cannot be backflowed because there is no positive pressure in the pipeline. Through the coordination of the above three steps, the probability of backflow in the vacuum toilet system can be systematically reduced, improving the reliability of the rail vehicle toilet and passenger comfort.

[0054] According to an embodiment of this application, the sealing status of the inlet hose valve connected to the inlet of the waste transfer box is detected, including: First, the control unit controls the vacuum generator to perform a vacuuming operation on the waste transfer box until the vacuum switch installed on the waste transfer box outputs a vacuum establishment signal; Second, in response to the vacuum establishment signal, the control unit shuts off the vacuum generator and the inlet hose valve, and after a first preset time delay, controls the opening of the toilet drain valve, wherein the first preset time is 3 seconds; Finally, within a second preset time after the toilet drain valve is opened, if the vacuum establishment signal output by the vacuum switch disappears, the control unit determines that the inlet hose valve has a sealing failure and issues a fault command, and the vacuum waste collection system is unusable, wherein the second preset time is 2 seconds.

[0055] According to embodiments of this application, by first establishing a stable negative pressure reference through vacuuming, then shutting off the vacuum source and opening the toilet drain valve, the objective criterion of whether the vacuum switch signal disappears quickly can be used to accurately identify whether the inlet hose valve has a fault of not closing tightly or failing to seal. This detection logic does not require the addition of an additional high-precision pressure sensor; it can be implemented using only the existing vacuum switch in the system, reducing hardware costs. This detection is performed before vehicle operation; once a seal failure is determined, the system is prohibited from operation or a maintenance procedure is initiated, thereby intercepting the potential risk of backflow before the vehicle starts.

[0056] In some specific embodiments, if the inlet hose valve is well sealed, when the toilet drain valve is opened, outside air can only enter the pipeline from the toilet side. Since the diameter of the toilet drain valve is usually small and the pipeline is short, the vacuum will not be lost instantly. Conversely, if there is a leak in the inlet hose valve, outside air will rush into the waste transfer box from the valve side, causing the vacuum switch signal to disappear within a short time (e.g., 2 seconds).

[0057] In some specific embodiments, setting the first preset time to 3 seconds and the second preset time to 2 seconds is a reasonable value that is matched with the pipeline volume, valve response characteristics and vacuum switch sensitivity. This can effectively distinguish between normal pressure relief and abnormal leakage, and avoid misjudgment due to too short a response time or failure to detect fault due to too long a response time.

[0058] According to an embodiment of this application, real-time monitoring of the closing status of each toilet drain valve includes: detecting the closing position information of the toilet drain valve in real time by a position sensor installed on each toilet drain valve, and outputting an abnormal signal to the control unit if the toilet drain valve is not strictly closed.

[0059] According to embodiments of this application, a position sensor is independently installed on each toilet drain valve, enabling direct and real-time detection of the mechanical closed position of each valve, rather than relying on indirect signals (such as air pressure changes or time estimations) to determine the valve status. When the drain valve fails to close properly due to foreign object obstruction, mechanical wear, or return spring failure, the position sensor immediately outputs an abnormal signal to the control unit. This mechanism achieves immediate fault detection. Compared to periodic inspections or manual checks, this method allows for continuous monitoring without stopping the system and can issue an alarm at the first sign of a fault, buying time for subsequent fault isolation. Furthermore, the position sensor directly detects the actual physical position of the valve, unaffected by environmental factors such as pipeline pressure fluctuations or media adhesion, resulting in more reliable detection results and effectively reducing the risk of backflow accidents due to misjudgment or missed judgment.

[0060] According to an embodiment of this application, disabling a faulty toilet corresponding to an abnormal toilet drain valve includes: first, in response to an abnormal signal, the control unit closes the abnormal toilet drain valve; second, if the control unit receives an abnormal signal again, it controls the faulty toilet to repeatedly perform multiple flushing actions; finally, after a predetermined number of flushing actions, if the control unit still receives an abnormal signal, it determines that the abnormal toilet drain valve has malfunctioned, the control unit outputs a fault signal and isolates the faulty toilet.

[0061] According to the embodiments of this application, firstly, upon receiving an abnormal signal, the control unit immediately attempts to close the toilet drain valve. This initial intervention helps resolve the issue of the toilet drain valve being partially closed due to control signal interference or slight valve jamming. If another abnormal signal is received, it indicates that simple closure has failed. In this case, the faulty toilet is controlled to repeatedly perform multiple flushing actions. The water flow impact and valve disc reciprocating motion during the flushing process may wash away or dislodge any jammed foreign objects, allowing the valve to return to normal. Only if the abnormal signal persists after a predetermined number of flushing actions does the system ultimately determine it as a hardware fault and perform isolation operations, prohibiting the toilet from further use. This progressive logic processing method effectively distinguishes between temporary recoverable faults and permanent hardware failures, avoiding unnecessary equipment downtime caused by directly cutting off the toilet due to momentary foreign object jamming. At the same time, once a permanent fault is confirmed, it is decisively isolated, eliminating the risk of the faulty toilet becoming a backflow channel during subsequent system emptying, achieving a good balance between system availability and safety.

[0062] In some specific embodiments, the predetermined number of times is 5.

[0063] According to an embodiment of this application, the isolation operation includes: the control unit prohibits the faulty toilet from performing flushing and sewage discharge actions, closes the drain valve of the abnormal toilet, and outputs a fault alarm signal.

[0064] According to the embodiments of this application, the isolation operation's prohibition of flushing and sewage discharge directly prevents the user or system from subsequently using the faulty toilet, avoiding the risk of backflow caused by attempting sewage discharge again when the toilet's drain valve cannot be closed normally. Even though the valve is determined to be faulty, the control system still issues a closing command to place the toilet drain valve in the most closed position possible, reducing the cross-sectional area of ​​the passage for sewage or gas to flow back. The output of a fault alarm signal promptly notifies the crew or ground maintenance personnel of the specific location and nature of the faulty toilet, facilitating subsequent repairs or temporary closure of the toilet. Through the above isolation operation, the faulty toilet is completely separated from the vacuum sewage system, neither affecting the use of other normal toilets in the same carriage nor eliminating the potential for the faulty point to become a weak link in the entire system's emptying process.

[0065] According to an embodiment of this application, the control unit controls the release of abnormal pressure in the pipeline, including: in response to a positive pressure venting command issued by the control unit to the waste transfer tank, the wastewater drain valve of the wastewater tank is opened, so that the pipeline between the toilet drain valve and the inlet hose valve is connected to the atmosphere through the wastewater transfer tank, thereby releasing the abnormal positive pressure in the pipeline.

[0066] According to an embodiment of this application, after the control unit issues a positive pressure venting command for the waste transfer tank, venting is not performed immediately. Instead, the wastewater drain valve of the wastewater tank is opened first. The wastewater tank is originally used to collect washing wastewater, and its drain valve is open to the outside atmosphere. When the wastewater drain valve is opened, the pipeline between the toilet drain valve and the inlet hose valve is connected to the atmosphere through the wastewater tank. If there is abnormal positive pressure in the pipeline, it will be naturally discharged into the atmosphere. This design does not require any additional valves or pipelines for pressure relief; it can be achieved simply by reusing the existing wastewater tank and wastewater drain valve in the system.

[0067] In some specific embodiments, the pressure relief action is triggered after the positive pressure evacuation command is issued but before the actual application of positive pressure. This ensures that the pipeline pressure is actively adjusted to a safe range before the positive pressure evacuation operation of the waste transfer box is performed. Even if there is a slight mis-closure of the toilet drain valve or the waste inlet hose valve, since there is no positive pressure inside the pipeline, the waste cannot obtain the power to be ejected in reverse, thus eliminating the physical possibility of backflow from the pressure condition itself.

[0068] According to an embodiment of this application, applying positive pressure to the waste transfer box to empty the waste includes: after the abnormal positive pressure is released, the control unit opens the drain hose valve of the waste transfer box and applies positive pressure to the waste transfer box so that the waste in the waste transfer box is transferred to the waste tank.

[0069] According to an embodiment of this application, opening the drain hose valve and applying positive pressure directly acts on the waste transfer tank, using the external positive pressure to push the temporarily stored waste into the waste tank. During the depressurization phase, only the wastewater discharge valve is opened; during the dredging phase, only the drain hose valve is opened and positive pressure is applied. The depressurization and dredging actions are strictly separated in sequence, and the two pathways do not interfere with each other, avoiding the risk of positive pressure leakage or waste entering the wrong pipeline due to opening multiple pathways simultaneously.

[0070] In some specific embodiments, the drain hose valve is opened and positive pressure is applied to the sludge transfer box only after the abnormal positive pressure has been completely released. This sequence ensures that the positive pressure downstream of the sludge transfer box is not transmitted back to the pipeline area between the drain valve and the inlet valve during the entire emptying process, thereby minimizing the risk of backflow.

[0071] In some specific embodiments, compared to evacuation methods that rely on gravity or negative pressure suction, positive pressure evacuation has a stronger driving force and a faster evacuation speed, making it particularly suitable for the bottom space of rail vehicles with long pipelines or bends.

[0072] According to an embodiment of this application, after the waste is drained, the wastewater discharge valve is controlled to close after a delay to ensure that the residual positive pressure in the pipeline is released.

[0073] According to embodiments of this application, during positive pressure evacuation, a small amount of residual positive pressure may remain in the pipeline that has not been completely released. If the wastewater drain valve is closed immediately after evacuation, the pipeline is once again isolated from the atmosphere, and the residual positive pressure will be trapped inside the pipeline. If a small gap appears in the toilet drain valve or the inlet hose valve in the subsequent system, this residual pressure may still cause slow leakage or instantaneous backflow of waste. By delaying the closure of the wastewater drain valve, keeping the pipeline connected to the atmosphere for a period of time, it can be ensured that the pressure inside the pipeline completely returns to the ambient atmospheric pressure, thereby eliminating any residual back pressure.

[0074] In some specific embodiments, the duration of the delayed closure can be preset based on factors such as pipeline volume and valve response characteristics, ensuring complete pressure relief while avoiding excessive delays that could affect system efficiency. This measure, as the final step in the pressure relief process, forms a closed loop with the pressure relief opening action; that is, the pressure relief channel is opened first, and then closed last, ensuring a complete and thorough pressure relief process without leaving any hidden dangers.

[0075] According to an embodiment of this application, the aforementioned anti-backflow control method further includes: before vacuum detection, the control unit controls the wastewater discharge valve of the wastewater tank to open to release residual positive pressure and avoid residual positive pressure interfering with vacuum detection.

[0076] According to an embodiment of this application, if there is an abnormal positive pressure in the pipeline between the toilet drain valve and the inlet hose valve before vacuum testing, this positive pressure will flow back into the waste transfer tank when a vacuuming operation is subsequently performed. This causes a time delay in the vacuum switch's output vacuum establishment signal or even prevents the establishment of a stable vacuum, resulting in a misjudgment of the sealing test. The inlet hose valve, which was originally well-sealed, may be misjudged as leaking due to interference from the initial positive pressure. By actively opening the wastewater drain valve before vacuuming, the pipeline is connected to the atmosphere, and the pressure in the pipeline is pre-adjusted to the ambient atmospheric pressure, eliminating uncertain initial pressure factors.

[0077] Figure 2 This is a schematic diagram of the structure of a vacuum waste collection system in one embodiment of this application.

[0078] In another aspect of this application, a vacuum waste collection system for rail vehicles is also disclosed, such as... Figure 2 As shown, it includes a toilet, a wastewater tank, a waste transfer tank 4, a waste tank 5, a vacuum generator 6, and a control unit (DTC). The toilet is designed to collect waste, and its outlet is equipped with a drain valve to control waste from the toilet into the pipeline. A wastewater tank is designed to collect washing wastewater 32, and its outlet is equipped with a wastewater drain valve 31 to control the discharge of wastewater from the tank and gas from the pipeline. A waste transfer box 4 is designed to temporarily store waste, and its inlet and outlet are equipped with a waste inlet hose valve (HOSE valve) 41 and a waste outlet hose valve (HOSE valve) 42, respectively, to control the entry or exit of waste into or from the waste transfer box 4. A waste tank 5 is designed to store final waste. A vacuum generator 6 is connected to the waste transfer box 4 via a vacuum hose valve (HOSE valve) 61, and is designed to generate vacuum and positive pressure. A control unit is located on the rail vehicle and is electrically connected to the toilet drain valve, waste inlet hose valve 41, wastewater drain valve 31, waste outlet hose valve 42, and vacuum generator 6, respectively. The control unit executes the aforementioned anti-backflow control method.

[0079] According to embodiments of this application, the vacuum waste collection system is equipped with multiple dedicated containers: a toilet bowl for collecting waste, a wastewater tank for collecting washing wastewater 32, a waste transfer tank 4 for temporary waste storage, and a waste tank 5 for final storage. This hierarchical storage architecture separates the paths for waste collection and wastewater collection, avoiding cross-contamination of pipelines caused by the mixing of different media. The toilet bowl drain valve, wastewater inlet hose valve 41, wastewater drain valve 31, and wastewater outlet hose valve 42 are respectively arranged at key positions in each channel, each controlled by a control unit, forming multiple independently operable switching nodes. The control unit is electrically connected to all valves and the vacuum generator 6, executing the aforementioned anti-backflow control method. This means that the entire system not only has the hardware foundation to complete basic waste collection and discharge functions, but also incorporates a complete process control logic from detection and monitoring to pressure relief.

[0080] In some specific embodiments, the vacuum toilet system can determine whether the inlet hose valve 41 is properly sealed before operation via vacuum detection; disable faulty toilets by monitoring the status of the drain valve during operation; and release abnormal pressure through the wastewater drain valve 31 after shutdown before performing positive pressure venting (positive pressure is introduced into the vacuum toilet system through the positive pressure inlet 7). These functions do not rely on external detection equipment or manual intervention, but are automatically completed by the control unit using existing resources such as the vacuum generator 6 and vacuum switches in the system. Therefore, while meeting basic sewage discharge functions, the vacuum toilet system integrates a relatively complete backflow prevention capability, which helps reduce the probability of the rail vehicle toilets being out of service due to backflow failure.

[0081] In some specific embodiments, the vacuum toilet system includes multiple toilets and their drain valves, such as a first toilet 1, a first drain valve 11, a second toilet 2, and a second drain valve 21.

[0082] In some specific embodiments, the wastewater transfer tank 3 is equipped with a water tank for collecting washing wastewater 32 and an overflow valve 33 to prevent wastewater from flowing out.

[0083] According to an embodiment of this application, the aforementioned vacuum waste collection system further includes a vacuum switch, which is disposed on the waste transfer box 4. The vacuum switch is suitable for detecting the vacuum level inside the waste transfer box 4 and outputting a vacuum status signal.

[0084] According to an embodiment of this application, when the vacuum level inside the waste transfer box 4 reaches a preset value, the vacuum switch outputs a vacuum establishment signal. By directly installing the vacuum switch on the waste transfer box 4, it can accurately reflect the pressure changes inside the waste transfer box 4, avoiding detection deviations caused by pipeline pressure loss or signal delay. Furthermore, the switching signal output by the vacuum switch does not require additional signal conditioning circuitry and can be directly connected to the input interface of the control unit. It has a fast response speed and strong anti-interference capability, which helps improve the accuracy and real-time performance of fault detection in the entire vacuum waste collection system.

[0085] In some specific embodiments, the vacuum signal is crucial for several key steps in the aforementioned control method. During the pre-operation sealing status detection of the inlet hose valve 41, the control unit needs to determine whether vacuuming is complete based on whether the vacuum switch outputs a vacuum establishment signal, and uses this as a benchmark to further detect valve leakage. In the self-test process or fault diagnosis scenario during operation, the vacuum status signal provided by the vacuum switch can also help determine whether there is abnormal air leakage in the system.

[0086] According to an embodiment of this application, the aforementioned vacuum toilet system further includes a position sensor disposed on the toilet drain valve, which is suitable for real-time detection of the mechanically closed state of the toilet drain valve and outputting a position signal.

[0087] According to embodiments of this application, the position sensor is directly installed on the valve body of the toilet drain valve, detecting the actual physical position of the valve disc or valve core, rather than relying on indirect methods such as pipeline pressure changes or time estimation to determine whether the valve is closed. This direct detection method can effectively eliminate misjudgments caused by factors such as system pressure fluctuations, media adhesion, and sensor drift, and the detection results are closer to the true mechanical state of the valve. The real-time output position signal allows the control unit to monitor every closing action of the drain valve. Once the valve fails to close completely, the signal changes immediately, and the control unit can detect the anomaly within the same control cycle without waiting for pressure anomalies or user feedback in subsequent operation stages. This instantaneous sensing capability provides a reliable data foundation for subsequent flushing attempts, fault confirmation, and isolation operations, enabling the control unit to proactively intervene before backflow conditions form and disconnect the faulty toilet from the system. In addition, the switching signal output by the position sensor has the same format as the vacuum switch signal, which facilitates unified processing by the control unit and reduces the complexity of the signal interface.

[0088] In some specific embodiments, the position sensor is installed on the toilet drain valve body. The sensor valve body has a threaded hole. After the sensor slides into place along the slide groove, the tightening screw is screwed in from above the threaded hole until the front end of the screw is pressed into the plastic valve body.

[0089] It should be noted that the described embodiments are merely some, not all, of the embodiments described in this application. Other embodiments obtained by those skilled in the art based on the embodiments described in this application without inventive effort are all within the scope of protection of this application.

[0090] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above descriptions are merely specific embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preventing backflow control in a vacuum toilet system for rail vehicles, comprising: Before the rail vehicle is put into operation, the control unit performs a vacuum test on the sealing status of the valve of the sewage inlet hose connected to the sewage transfer box inlet, obtains the test result, and if the test result is qualified, the control unit controls the vacuum sewage collection system to enter the standby state, and the rail vehicle is ready to run. During the operation of the rail vehicle, the control unit monitors the closing status of each toilet's drain valve in real time and disables the faulty toilet corresponding to the abnormal state of the drain valve, so as to prevent the faulty toilet from backflowing. The sewage in the toilet is transported to the sewage transfer box through the pipeline. After the rail vehicle stops running, the control unit controls the release of abnormal pressure in the pipeline to prevent backflow, and controls the application of positive pressure to the sewage transfer box to empty the sewage.

2. The anti-backflow control method according to claim 1, wherein, The sealing condition of the inlet hose valve connected to the waste transfer box inlet is checked, including: The control unit controls the vacuum generator to perform a vacuuming operation on the waste transfer box until the vacuum switch installed on the waste transfer box outputs a vacuum establishment signal; In response to the vacuum establishment signal, the control unit shuts off the vacuum generator and the sewage inlet hose valve, and after a first preset time delay, controls the toilet drain valve to open, wherein the first preset time is 3 seconds; Within a second preset time after the toilet drain valve is opened, if the vacuum establishment signal output by the vacuum switch disappears, the control unit determines that the inlet hose valve has failed to seal and issues a fault command, rendering the vacuum toilet system unusable. The second preset time is 2 seconds.

3. The anti-backflow control method according to claim 1, wherein, Real-time monitoring of the closing status of each toilet's drain valve includes: The position sensor installed on each toilet drain valve detects the closed position information of the toilet drain valve in real time, and outputs an abnormal signal to the control unit if the toilet drain valve is not strictly closed.

4. The anti-backflow control method according to claim 3, wherein, The following toilets are considered faulty and require disabling the drain valve due to an abnormal state: In response to the abnormal signal, the control unit closes the toilet drain valve in the abnormal state; If the control unit receives the abnormal signal again, it will control the faulty toilet to repeat the flushing action multiple times. If, after a predetermined number of flushing actions, the control unit still receives the abnormal signal, it determines that the toilet's drain valve is malfunctioning, and the control unit outputs a fault signal and isolates the malfunctioning toilet.

5. The anti-backflow control method according to claim 4, wherein, The isolation operation includes: The control unit prevents the faulty toilet from performing flushing and sewage discharge actions, closes the drain valve of the toilet in the abnormal state, and outputs a fault alarm signal.

6. The anti-backflow control method according to claim 1, wherein, The control unit controls the release of abnormal pressure within the pipeline, including: In response to the positive pressure venting command issued by the control unit to the waste transfer tank, the wastewater drain valve of the wastewater tank is opened, so that the pipeline between the toilet drain valve and the wastewater inlet hose valve is connected to the atmosphere through the wastewater tank, releasing the abnormal positive pressure in the pipeline.

7. The anti-backflow control method according to claim 6, wherein, Applying positive pressure to the waste transfer box to empty the waste includes: After the abnormal positive pressure is released, the control unit opens the drain hose valve of the waste transfer box and applies positive pressure to the waste transfer box so that the waste in the waste transfer box is transferred to the waste tank.

8. The anti-backflow control method according to claim 7, wherein, After the waste is discharged, the wastewater discharge valve is closed with a delay to ensure that the residual positive pressure in the pipeline is released.

9. The anti-backflow control method according to claim 8 further includes: Before the vacuum test, the control unit controls the wastewater drain valve of the wastewater tank to open, so as to release the residual positive pressure and prevent the residual positive pressure from interfering with the vacuum test.

10. A vacuum toilet system for rail vehicles, comprising: A toilet bowl suitable for collecting waste, wherein the outlet of the toilet bowl is provided with a toilet drain valve to control the waste from the toilet bowl into the pipeline; Wastewater tank, suitable for collecting washing wastewater, the outlet of the wastewater tank is equipped with a wastewater discharge valve to control the discharge of wastewater in the wastewater tank and gas in the pipeline; A waste transfer box is suitable for temporarily storing waste. The waste transfer box is equipped with an inlet hose valve and a outlet hose valve to control the entry of waste into or exit from the waste transfer box. Waste bins are suitable for storing final waste. A vacuum generator, connected to the waste transfer box, is suitable for generating vacuum and positive pressure; The control unit is arranged on the rail vehicle and is electrically connected to the toilet drain valve, the sewage inlet hose valve, the wastewater drain valve, the sewage discharge hose valve and the vacuum generator respectively. The control unit executes the anti-backflow control method according to any one of claims 1 to 9.

11. The vacuum waste collection system according to claim 10, further comprising: A vacuum switch is installed on the waste transfer box. The vacuum switch is used to detect the vacuum level inside the waste transfer box and output a vacuum status signal.

12. The vacuum waste collection system according to claim 10, further comprising: A position sensor is installed on the toilet drain valve, which is suitable for detecting the mechanical closing state of the toilet drain valve in real time and outputting a position signal.

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