103 results about "Negative pressure wave" patented technology

A control system for a high frequency oscillating ventilator (HFOV) includes and oscillator controller and a mean airway pressure (MAP) controller. The HFOV includes a reciprocating piston which is adapted to generate positive and negative pressure waves for delivery to a patient airway. The oscillator controller comprises a pair of closed loop control circuits including an oscillator pressure loop and a centering loop which are collectively adapted to regulate frequency and amplitude of piston reciprocations and centering of the piston. The MAP controller comprises a closed loop control circuit that is adapted for regulating MAP at the patient utilizing feedback in the form of patient circuit pressure. Likewise, the oscillator controller utilizes patient circuit pressure as well as piston displacement feedback in order to regulate movement of the piston.

Provided is a high frequency oscillating ventilator comprising a housing assembly, a linear actuator, a linear coil, a piston mounted on a pushrod, a diaphragm dividing a housing into a first and second side and having an opening formed on the second side that is fluidly connected to the patient's airway for delivering gas thereto. The linear actuator is fixedly mounted to the housing assembly and has a linear coil coaxially disposed therewithin. A pushrod supports the linear coil on the linear actuator to allow relative axially sliding therebetween. The piston is directly mounted to the diaphragm such that reciprocation thereof as effectuated by the linear coil cooperating with the linear actuator alternately produces positive and negative pressure waves in the gas in the patient's airway.

The invention provides a system and a method for monitoring pipeline vibration. The system comprises a plurality of pipeline vibration monitoring devices arranged on pipeline monitoring points and a central control device connected with each pipeline vibration monitoring device, wherein each pipeline vibration monitoring device comprises a detection device, a conversion device, a connection device, an acquisition device and an analysis processing device which are connected in turn. The method comprises the following steps: establishing a background frequency spectrum; acquiring and processing signals; determining event attribute; determining a fault point and giving an alarm. The method has the advantages that the method detects pipeline state by acquiring pipeline noises, and does not have the disadvantages of a negative pressure wave detection method which is susceptible to low pressure, temperature change and transported substance density; moreover, as for noise influence, the method is only sensitive to noises with the intensity and frequency equivalent to those of an occurring event, and noises at other frequency do not generate greater influence on the method.

The invention relates to a leakage monitoring system, method and device for a pipeline and a server. The method includes the steps that infrasonic signal, pressure, temperature and flow data in the pipeline are obtained; infrasonic leakage detection is performed according to an infrasonic signal so that the leakage state and the leakage occurrence time of the pipeline can be obtained; negative pressure wave leakage detection is performed according the pressure and temperature data so that the leakage state and the leakage occurrence time of the pipeline can be obtained; flow balance leakage detection is performed according to the flow data so that the leakage state of the pipeline can be obtained; the leakage occurrence time obtained according to infrasonic leakage detection and/or leakage occurrence time obtained according to negative pressure wave leakage detection are/is output to the server. The leakage monitoring device integrating the three leakage monitoring methods achieved through infrasonic waves, negative pressure waves and flow balance can achieve the effects that the methods are complementary, the leakage alarming rate is increased, and the error alarming rate and the missing alarming rate are reduced.

The invention provides a method for locating the leakage position of an ore pulp conveying pipe, relates to a conveying control method, in particular to the method for determining the leakage position when the conveying pipe is blocked in the long-distance iron concentrate ore pulp conveying process. According to the method, by the adoption of a negative-pressure wave method, when the iron concentrate pulp pipe generates leakage, concentrate pulp at a leakage point flows away rapidly due to the difference between the internal pressure and the external pressure of the pipe, and pressure drops down; liquid on both sides of the leakage point is supplemented to the leakage point due to the pressure difference; the above processes are sequentially passed to an upstream pump station and a downstream pump station through the concentrate pulp pipe, that is, negative-pressure waves propagating at a certain speed are generated at the leakage point; and the position of the leakage point can be worked out according to the time difference generated when negative-pressure weaves generated at the leakage point are propagated to the upstream pump station and the downstream pump station and the propagation speed of the negative pressure waves in the pipe. The method has the beneficial effects of being less in required devices, low in operation cost, simple in operation and the like and is superior to an existing method for determining the leakage position of the pipe.

The invention provides a pipeline leakage detection method and device and relates to the field of pipeline leakage monitoring. The pipeline leakage detection method comprises the steps of obtaining anegative pressure wave signal caused by pipeline leakage; preprocessing the negative pressure wave signal to obtain the dynamic change sequence of pressure along a pipeline; determining the interval of a leakage point on the basis of the dynamic change sequence of pressure along the pipeline; and obtaining the position of the leakage point on the basis of dynamic change sequences of pressure at the two ends of the interval of the leakage point. According to the method and the device, the pipeline is detected in a segmented manner by multiple sensors arranged in the pipeline so as to determinethe interval of the leakage point, then the leakage point is positioned on the basis of the interval of the leakage point, the positioning precision is high, the site operability is high, and the method and the device can be widely applied to leakage detection of long oil and gas transmission pipelines and city water supply and heat supply pipelines.

The invention discloses an oil gas pipeline leakage detecting method based on pressure signal inflexion that belongs to pipeline monitoring technology. It includes the following steps: collecting the output value list of the entrance and exit of the pipeline from the pumping station pressure transmitter; sending to computer; taking conversion process to make the pressure signal wave mutation inflexion obvious; identifying the moment of the inflexion happening, and gaining time table; then, judging whether the pipeline is leakage. The advantage of the invention are simple, practical, and can effectively decreases the miss alarming rate, increases the location accuracy of leakage. It is suited for detecting the oil gas pipe in normal transferring condition.

The invention provides a pipeline leakage monitoring system and method based on sound wave and negative pressure wave hybrid monitoring, and relates to the technical field of pipeline risk prediction.The system comprises pressure sensors, sound wave sensors, lower computers, exchangers and upper computers which are located at the head end and the tail end of a pipeline, wherein the lower computers control the pressure sensors and the sound wave sensors to acquire pressure and sound wave data, preprocess the pressure and sound wave data and then send the pressure and sound wave data to the upper computers through the exchangers, and the upper computers execute leakage monitoring programs in the upper computers, receive and analyze the pressure and sound wave data transmitted by the lower computers through pressure and sound wave data integration and storage modules, carry out secondary filtering, dimensionless processing and semi-supervised Fisher discriminant analysis processing on the acquired data through data processing module, judge whether the pipeline leaks or not through pipeline leakage monitoring modules, and carry out hybrid positioning on the pressure signals and the sound wave signals. According to the pipeline leakage monitoring system and method, noise interference can be better shielded, when a signal source is changed, the accuracy of the restored signals afterfiltering can be guaranteed, and positioning of leakage points can be more accurate.

The invention provides a detecting system and method for leakage of a water supply pipeline of an urban underground pipe gallery. The detecting system comprises a head end pressure detection module, a tail end pressure detection module, acoustic detection modules and an upper computer, wherein the head end pressure detection module and the tail end pressure detection module are located at the head end and the tail end of the water supply pipeline correspondingly, are of the same structure and are each provided with a pressure sensor and a real-time data acquisition device in sequence; and the acoustic detection modules and the upper computer are distributed between the head end and the tail end of the water supply pipeline. The acoustic detection modules are used for detecting acoustic waves of water current in the water supply pipeline; the upper computer is used for conducting rough positioning according to declining inflection points generated by negative pressure waves in the water supply pipeline and obtained through the head end pressure detection module and the tail end pressure detection module, and for conducting accurate positioning through the acoustic waves detected by the acoustic detection modules. According to the detecting system and method for leakage of the water supply pipeline of the urban underground pipe gallery, the pressure sensors are firstly utilized for rough positioning for leakage points, then acoustic sensors are utilized for conducting accurate positioning, and fast positioning and accurate alarming for leakage of the water supply pipeline of the urban underground pipe gallery are achieved accordingly.

The invention discloses a pipeline leakage location calculation method based on pressure difference. The calculation method comprises the following steps: establishing a pipeline leakage model; calculating an equation of negative pressure wave edge pipe attenuation; and finally, deducing the relationship between the pipeline leakage position and the pressure changes before and after pipeline leakage. In a simulation experiment, a negative pressure wave time-domain curve model is established for the first time according to fluid dynamics, the model is capable of simulating an actual pipeline, and dividing the negative pressure wave into three parts, namely respectively a steady state before leakage, an unsteady state during leakage and a steady state after leakage. An ANPW positioning algorithm and the traditional positioning algorithm can be compared by virtue of negative pressure wave simulated analysis, and the advantages of the ANPW positioning algorithm are obtained.

A water-saving valve assembly has a base, a control valve device and a buffer device. The control valve device is mounted in the base. The water-saving valve assembly is mounted on an exit of a water pipe. Users can control the flowing out or stopping of water in the water pipe via the control valve device. The buffer device provides a gradual effect of switching off and can effectively reduce positive and negative pressure waves generated in the water pipe. Noises and damage to the water pipe are also prevented.

The invention relates to a distributed optical fiber multi-parameter pipeline leakage positioning and warning system and a leakage positioning method. The distributed optical fiber multi-parameter pipeline leakage positioning and warning system comprises a sensing optical fiber laid in the same ditch as a pipeline and a DTS system connected with the sensing optical fiber. At least two negative-pressure wave monitoring devices are arranged on the pipeline. A negative-pressure wave monitoring system and the DTS system are both connected with a monitoring center through communication interfaces and the Ethernet network. Each negative-pressure wave monitoring device comprises a pressure flow transmitter connected with the pipeline, and the pressure flow transmitter is connected with a data acquisition unit. The data acquisition units are connected with GPS timing antennas. The distributed optical fiber multi-parameter pipeline leakage positioning and warning system has the beneficial effects that the defects that a negative-pressure wave monitoring and infrasonic wave leakage monitoring system cannot conduct monitoring and cannot conduct accurate positioning due to small leakage and adistributed optical fiber temperature leakage monitoring system cannot monitor leakage due to a low-temperature difference are overcome; based on the temperatures, obtained by a distributed optical fiber temperature measuring system, of all points, the wave velocity is calculated and corrected accurately, and accurate positioning of the leakage position is achieved.

The invention relates to the field of ore pulp pipeline safety maintenance, in particular to a positioning and alarming system and method for ore pulp pipeline leakage. According to the technical key points of the positioning and alarming system and method, the positioning and alarming system comprises two or more pressure sensors, a first flow sensor, a second flow sensor, a datum processor and an alarming device; the two or more pressure sensors are connected with the outer wall of an ore pulp pipeline along the flow direction of the ore pulp pipeline, and the space between the adjacent pressure sensors is the same; the first flow sensor is arranged at the beginning end of the ore pulp pipeline; the second flow sensor is arranged at the tail end of the ore pulp pipeline; and the datum processor is connected with the pressure sensors, the first flow sensor, the second flow sensor and the alarming device. The negative pressure wave method and the flow balance method are combined, the problem that leakage positioning of an existing ore pulp pipeline is inaccurate is solved, and the problems that in practical application, the negative pressure wave method cannot accurately determine the time difference of an upstream pressure sensor and a downstream pressure sensor to receive the pressure wave, and thus false judging of the leakage point position is caused are solved.

The invention discloses an oil and gas pipeline burst detecting and positioning method, and belongs to the technical field of oil and gas storage and transportation. The method comprises the steps that a first pressure sensor, a second pressure sensor and a sound wave signal sensor are arranged in a valve chamber or a field station on a pipeline to be detected at a certain distance, a negative pressure wave signal and a sound wave signal are received, negative pressure wave signal characteristic value and sound wave signal characteristic value are extracted to calculate alarm characteristic value, whether the pipeline to be detected bursts or not is determined, and according to the negative pressure wave signal and the sound wave signal, the leakage position of the pipeline to be detectedis calculated. According to the oil and gas pipeline burst detecting and positioning method, in combination with advantages of multiple detection methods, the false alarm probability is reduced, alarminformation can be conveniently found in time, meanwhile, the oil and gas pipeline burst positioning method is provided, the leakage position of the pipeline to be detected can be positioned, and theneeded device is compact in mounting, convenient to operate and capable of achieving independent positioning.

A controlling valve includes an outer sheet, an end cap and a control valve group. The control valve group is disposed between a flowing bore in the outer sheet and a water bore in the end cap. The controlling water valve is connected with the outlet of a water tube. When the control valve group is pushed upwards, the water bore in the end cap and the flowing bore in the outer sheet are closed in a predetermined sequence, then the water in the tube will not flow out. When the control valve group is pushed downwards, the flowing bore in the outer sheet and the water bore in the end cap are opened, then the water will flow out. When the water is stopped, the occurring positive or negative pressure wave is lowered, and then the vibration and the raspy noise will be avoided.