148 results about "Flow curve" patented technology

A technique for determining pump flow without using traditional sensors features steps and modules for creating a calibrated power curve at closed valve conditions at several speeds; calculating coefficients from a normalized power curve based on a pump's power ratio; and solving a polynomial power equation for flow at the current operating point. The calibrated power curve may be created by increasing the speed of the pump from a minimum speed to a maximum speed and operating the pump with a closed discharge valve. This data is used to correct published performance for shutoff power and best efficiency point power at rated speed in order to determine the pump's power ratio. It is also used to accurately determine closed valve power at the current operating speed. The pump's power ratio is determined by the equation: P_ratio=P_{shutoff @100%}/P_{BEP<sub2>—</sub2>corr}. The polynomial power equation may, for example, include a 3rd order polynomial equation developed using coefficients from the normalized power versus flow curve, and corrections may be made for speed, hydraulic efficiency and specific gravity in the polynomial power equation. Complex roots may be determined to solve the 3rd order polynomial equation using either Muller's method or some other suitable method, and the calculated actual flow may be determined for a specific operating point.

The present invention provides protection for centrifugal pumps while differentiating between dangerous operating conditions (e.g. dry running, minimum flow and runout) and/or conditions where transient conditions (e.g. closed valve operation) may occur and the protection can be revoked once the condition clears. The methodology utilizes a calculated flow value which can be mathematically determined from a calibrated closed valve power vs speed curve and/or various pump and motor parameters such as speed, torque, power and/or differential pressure or from calibrated flow curves stored in the evaluation device. The calculated flow value is then compared to threshold values of flow associated with these adverse operating conditions.

The invention relates to a method for predicting the dynamic mechanical property of a material based on a BP artificial neural network, aims at achieving the prediction of the dynamic mechanical property of the material through the BP artificial neural network, and belongs to the testing field of the dynamic mechanical property of the material. The principle of the method comprises the steps: collecting stress-strain data through employing a high-speed tensile test method, and obtaining a training sample set after normalization preprocessing; building a BP artificial neural network model through designing an input layer, a hidden layer and an output layer, and selecting a proper transfer function, a training function, and a learning function; carrying out the iterative training of the BP artificial neural network through employing the training sample set, and obtaining an optimal prediction network. The above prediction method can be used for the prediction of the dynamic mechanical property of the material, can achieve the quick prediction of a flow curve of the material at different strain rates in a short time, and can provide enough sample data for automobile safety simulation.

The invention provides an adjustment method for steam turbine control valve flows in a thermal power plant. The adjustment method includes the following steps that step1, a control valve optimization experiment is performed, all experimental data are determined, and a load up-and-down experiment needing to be performed for a current valve curve linear relation, a high control valve flow characteristic experiment, and determining on maximum strokes and sequence valve curves of all high control valve equalizing valves, sequence valve curves after on-line inspection and modification and maximum flow point positions of intermediate control valves are sequentially performed; step2, a control valve flow curve optimization scheme is obtained through calculation and analysis performed on control valve flow curve experimental data. The adjustment method can effectively improve the flow characteristic of steam turbine control valves, improve load variation and primary frequency modulation performance of a generator set, effectively improve adjustment quality of the generator set, and improve running safety and service life of high control valves and the intermediate control valves and economy of the set.

Tea leaves is used as raw material, by using water or solvent, to extract tea-polyphenol, then settle, centrifugal separation, column absorbing, extracting by ethyl acetate, vacuum concentrating, drying to obtain crude tea-polyphenol. Said crude product is then dissolved in water, absorbed by resin column, washed-off by agent gradient adding-in, based-on standard flowing curve to obtain 7 monomer catechins with purity>99%. For this purpose, full automatic absorbing resin column is equiped with metering pump to adjust fed-in of water, solution and solvent, HPLC real-time monitoring and pick-correcting to washing-off liquid is achieved by proportional flow-splitter. Automatic back-wash and resin-exchanging are achieved by being equiped with over-flow hole, resin discharging hole and others.

A water-soluble interjacent complex that includes a first water-soluble polymer and one or more water-soluble monomers polymerized to form a second water-soluble polymer in the presence of the first water-soluble polymer. The water-soluble interjacent complex forms a solution in water that is free of insoluble polymer particles. The interjacent complexes may be used to treat a waste sludge by adding an effective amount thereof to the waste sludge. The interjacent complexes may also be used in making paper by adding an effective amount thereof to a pulp or a forming sheet at a suitable location on a paper making machine. The interjacent complexes may further be used as a rheology modifier in aqueous systems by adding an effective amount thereof to an aqueous medium to effect a desired viscosity, rheology, or flow curve property.

The invention discloses a method determining a controllable vibration source best low-frequency scanning signal. Equal-frequency scanning signals are adopted, vibration source output force is increased gradually to carry out excitation, the least square method is used for carrying out matching on measured vibration source low-frequency sampling point actual output maximum output force, a controllable vibration source low-frequency output curve is determined according to a fitting heavy punch maximum displacement curve and the focus of a system flow curve, a low-frequency section scanning time length is calculated, the frequency, amplitude and phase of each sampling point of the low-frequency section are calculated, a scanning signal is generated to carry out practical testing on the vibration source, and the best low-frequency scanning signal is obtained until a vibration result does not exceed heavy hammer displacement limitation or the flow limitation. According to the method determining the controllable vibration source best low-frequency scanning signal, the low-frequency components of the controllable vibration source scanning signal are significantly enhanced, the method determining the controllable vibration source best low-frequency scanning signal is suitable for an existing controllable vibration source, can exert the maximum potential of the low frequency of the controllable vibration source, the low frequency signal is small in signal distortion, the output frequency spectrum of the controllable vibration source is smooth and white-noised, and the controllable vibration source can be protected well.

The invention discloses a method for acquiring thrust limiting rules of big and small accelerators of an aircraft engine. The method comprises the following steps: calculating a state deviation valueof the engine, and determining whether the engine is in an acceleration state according to the state deviation value; if the engine is in the acceleration state, acquiring a low-pressure rotor conversion rotational speed control rule curve of the engine when parameters of the aircraft meet the first preset condition; and determining a low-pressure rotor conversion rotational speed corresponding toa first preset time in the low-pressure rotor conversion rotational speed control rule curve, and calculating a fuel oil flow curve of the engine according to the low-pressure rotor conversion rotational speed. By utilizing the control method implemented in the invention, the supply amounts of the fuel oil flow during the actions of the big and small accelerators of the engine can be independently controlled, and the requirement of the thrust change rate is realized.

The invention discloses a steam turbine flow curve identification and optimization method based on power value calculation. The method includes the following steps that firstly, a plurality of sampling test points are set, and real-time working condition data are collected; secondly, vacancy working condition data and abnormal working condition data are deleted; thirdly, an output power value, a main steam pressure value and a total valve position value are selected to continuously stabilize the real-time working condition data of a plurality of sampling periods, and mean value treatment is carried out on various parameters; fourthly, a target data set is mined through the K-central point algorithm; fifthly, on the basis of power value calculation, a steam turbine adjustment valve bank flow characteristic curve under specific main steam pressure is identified; and sixthly, a steam turbine adjustment valve bank flow characteristic curve under rated main steam pressure is extracted, and a sector with unreasonable linearity is analyzed and optimized. The steam turbine flow curve identification and optimization method can be used for identifying the actual flow characteristic curve under the specific main steam pressure of a steam turbine adjustment valve bank, so that the specific adjustment valve bank flow characteristic curve is consistent with the actual curve, and safe and stable operation of a steam turbine unit is guaranteed.

A PVC pipe connector for underground sprinkler systems has one or more curved sections with a long low angled curve conducive to smooth laminar flow. The smooth flow curved section is incorporated in stretched elbow, curved Y, and curved T pipe connectors.

The invention discloses a method for calibrating a nonlinear proportional valve of a respirator. The method is achieved through a calibration unit on the respirator, after a proportional valve calibration mode is entered in, the closing effect of the proportional valve is detected first, if the proportional valve passes the detection, calibration is continued, then the calibration unit detects and records the minimum valve opening point voltage value Vmin and the maximum valve opening point voltage value Vmax of the proportional valve, a stepping value f is calculated and recorded, then the calibration unit drives the proportional valve by using the stepping valve f as steeping output drive voltages Vn, the flow values Qn flowing through the proportional valve under all driving voltages Vn are detected through a flow sensor, at last, the calibration unit generates a voltage-flow table according to detected data, the data in the voltage-flow table are fit to be n fitting straight lines to be stored, and calibration is achieved. According to the method, the voltage-flow curve of the nonlinear proportional valve is locally linearized, the voltage-flow relation of the nonlinear proportional valve can be well matched, the calculation process is simplified, and the accuracy of the calibration process is improved.

A technique for determining pump flow without using traditional sensors features steps and modules for creating a calibrated power curve at closed valve conditions at several speeds; calculating coefficients from a normalized power curve based on a pump's power ratio; and solving a polynomial power equation for flow at the current operating point. The calibrated power curve may be created by increasing the speed of the pump from a minimum speed to a maximum speed and operating the pump with a closed discharge valve. This data is used to correct published performance for shutoff power and best efficiency point power at rated speed in order to determine the pump's power ratio. It is also used to accurately determine closed valve power at the current operating speed. The pump's power ratio is determined by the equation: Pratio=Pshutoff @100%/PBEP<SUB2>-</SUB2>corr. The polynomial power equation may, for example, include a 3rd order polynomial equation developed using coefficients from the normalized power versus flow curve, and corrections may be made for speed, hydraulic efficiency and specific gravity in the polynomial power equation.

The present invention provides protection for centrifugal pumps while differentiating between dangerous operating conditions (e.g. dry running, minimum flow and runout) and/or conditions where transient conditions (e.g. closed valve operation) may occur and the protection can be revoked once the condition clears. The methodology utilizes a calculated flow value which can be mathematically determined from a calibrated closed valve power vs speed curve and/or various pump and motor parameters such as speed, torque, power and/or differential pressure or from calibrated flow curves stored in the evaluation device. The calculated flow value is then compared to threshold values of flow associated with these adverse operating conditions.

The invention relates to the technical field of natural gas exploitation and in particular relates to a building method and an application of a three parameter-gas well drainage gas recovery technology optimizing model. A difficulty of rapid selection of drainage gas recovery technology for water-producing gas well is solved. The building method comprises steps of first, collecting production parameters of a water-producing gas well of a gas field, then calculating different daily gas production of a given oil pipe aperture and natural gas critical liquid carrying flow under a water-gas ratio at different well depths, drawing out natural gas critical liquid carrying flow curves (a,b) of maximum and minimum oil pipe apertures on daily gas production, water-gas ratio and well depth three-dimensional model, and drawing out a curve (c) with liquid production amount being 95m<3> on the three-dimensional model. The natural gas critical liquid carrying flow calculated by the method meets on-site production condition in a better way; and the building method is advantaged by quick determination of gas well drainage gas recovery technology based on simple parameters such as daily gas production, water-gas ratio and the well depth.

The invention relates to a bandwidth optimized multimode fiber and a manufacturing method thereof. The multimode fiber comprises three parts, including a fiber core, a quartz glass cladding and a coating with graded index profile. By adopting the method of optimizing the impurity gas flow curve, the refractive index profile parameter of a fiber core is controlled to optimize the optimal bandwidth of the fiber at the communication window of 850nm.The largest change of the differential mode time delay of the fiber is less than 0.22ps/m, the over-filled launch bandwidth is larger than 3,500MHz.km and 500MHz.km respectively at 850nm and 1,300nm and the valid mode bandwidth is larger than 4,700MHz.km and 500MHz.km respectively at 850nm and 1,300nm.The multimode fiber of the invention decreases the chromatic dispersion between modes and the time delay and increases transmission bandwidth, thereby not only meeting the application requirement of a low speed network, but also meeting the application requirement of a gigabit high speed broadband network.

The invention relates to the field of mechanical property characterization, in particular to a virtual prediction method for a material hardening behavior under a large strain condition. The method comprises the following steps: obtaining force displacement and stress-strain data through a uniaxial tension test, fitting a stress-strain curve obtained through the test, establishing a finite elementmodel, simulating a uniaxial tension test process, comparing force displacement results of the simulation and the test, correcting model parameters according to a comparison result, and determining areasonable hardening model. According to the method, the mechanical behavior of the material in the plastic deformation process under the condition of large strain can be accurately predicted by utilizing a finite element method and a uniaxial tension test result. Due to the fact that the maximum strain often exceeds 0.5 in the body forming process, test data of the large strain cannot be obtained generally in the uniaxial tension test. By optimizing the parameters of the material hardening model, the flow curve of the material after epitaxy can be obtained, and the metal flow of the materialin the forging, extruding and rolling processes can also be predicted.

The invention relates to a loxiong viscosity behavior measuring method of a high-viscosity modified asphalt and an application thereof, which comprises the following steps: A. using the shearing rate scan test to obtain the viscosity-shearing rate flow curve of the high-viscosity modified asphalt at 60 DEG C; and B. fitting the curve obtained in the step A to obtain the 60 DEG C zero shear viscosity. The 60 DEG C zero shear viscosity obtained by using the method can be used for evaluating the viscosity behavior of the high-viscosity modified asphalt in a pavement structure. The invention is based on following references: the high-viscosity modified asphalt presents the characteristic of pseudo-plastic fluid at the shearing rate of 1.25*10<-5>s<-1>-1250s<-1>, the viscosity tends to be the zero shear viscosity in a first Newtonian region, and the common range in the first Newtonian region is completely matched with the shearing rate range in the pavement structure in the aspect of magnitude order, so the 60 DEG C zero shear viscosity can effectively reflect the viscosity characteristic of the high-viscosity modified asphalt in the pavement structure.

The invention discloses a highway traffic jam locating and searching method which is implemented on the basis of monitoring systems arranged on the way. The method includes jam area searching and jam point locating and searching. As for a monitoring system which is visual and can fully monitor road situations between two monitoring points, the jam area searching mode is adopted. As for a monitoring system which is visual but can not fully monitor the road situations between the two monitoring points and a non-visual monitoring system, the jam point locating and searching mode is adopted. The jam point locating and searching mode includes the steps that traffic flow data of multiple monitoring points of the upstream of the minimum traffic flow obtained through the monitoring system are fitted into an upstream flow curve; traffic flow data of multiple monitoring points of the downstream of the minimum traffic flow are fitted to form a downstream flow curve; the intersection of the two curves is obtained to serve as a jam point. By means of the method, specific positions of traffic jams and accidents and particularly blind areas between the monitoring points can be accurately located, and adverse effects of rainy and snowy days can be overcome.

The invention discloses a method for setting a valve flow characteristic curve of a steam turbine and belongs to the technical field of steam turbines. An overlap function is calculated by using datain single valve operation of a unit to obtain a new valve flow curve, and the reliability of a new characteristic curve is verified by using the data obtained in sequence valve operation of the unit.According to the method, valve flow characteristic parameters of the steam turbine can be completely and specifically set, so that switching between single valve and sequence valves is smooth, steam flow change is gentle during switching, load fluctuation is small, segment temperature and vibration do not greatly change and safe and stable operation of the unit is ensured; the response rate of AGCis optimized and the primary frequency modulation effect is improved; the overlap of regulating valves is reduced to improve the economy of the unit; and computation is simplified by using MATLAB programming.