CN102662084A

CN102662084A - Performance sampling verification method for propeller current meter

Info

Publication number: CN102662084A
Application number: CN2012101418097A
Authority: CN
Inventors: 杨汉塘; 周冬生; 杨立丽; 王为朴
Original assignee: Nanjing Water Conservancy and Hydrology Automatization Institute Ministry of Water Resources
Current assignee: Jiangsu Nanshui Technology Co., Ltd.
Priority date: 2012-05-08
Filing date: 2012-05-08
Publication date: 2012-09-12

Abstract

The invention discloses a performance sampling verification method for a propeller current meter. According to the method, a relation of propeller helical angles alpha, an inner friction moment M of a rotary supporting component and the verification performance of a propeller current meter is established, and aiming at mass production, the values of the alpha and the M are precisely determined; the alpha values are finely grouped, and according to a method of non-random quota sampling for the totality, random sampling for groups and weighted statistics for a result, a sample machine is precisely verified under a still water condition; meanwhile, theoretical calculating values are supplemented in verification for analysis and reference for correcting errors in time; through the measures, the total precision of the sample machine is guaranteed to be high; meanwhile, medium high and low speed standard linear formulas are used to ensure that the use of a hydrological testing current meter is precise and convenient; in production, the defects of the traditional mass production are overcome, and the workloads of verification works, labor intensity, power consumption, equipment overhaul and maintenance, and the like are reduced by 2/3; and the operation of verification procedures is scientific and normative and conforms to a modern production mode and a national standardized technical policy, so that the method has the advantages of better scientific, social and economic benefits.

Description

A kind of propeller type current meter performance sampling calibration method

Technical field

The present invention relates to a kind of rivers hydrologic survey propeller type current meter performance sampling calibration method.

Background technology

1, current meter performance calibrating

Current meter is used to measure river waterflow speed, and its performance calibrating is to use the relative motion of object principle: suppose that river waterflow is static water body, during flow measurement, the current meter that is fixed on the measuring point then is movable body.The calibration equipment of design is the long tank of a straight line open channel in view of the above, lays track in both sides on the bank at it, and current meter is installed in the measuring point depths on the calibrating car measuring staff, with a series of speed V _TOperation detects current meter simultaneously and exports corresponding rotation speed n, supposes calibrating vehicle speed V _TBe standard input V, i.e. V _T=V, through the velocity rating flume calibrating, confirm high speed performance calibration equation:

V=a+bn (1)

In the formula: a is a constant; B is a propeller type current meter waterpower pitch.Annotate: this paper experimental formula is calculated and used: C, K represent.

In the formula (1), the decurrence part of straight line formula because the hydrodynamic(al) moment that flow velocity is low, the oar running is revolved in promotion is little, produces the motion of trackslipping so revolve oar, forms the low speed curve; China uses the low speed graphical representation at present, and Germany uses the near linear formulate.

2, the problem of the calibrating of current meter large-lot production at present existence

It is many to produce calibrating instrument quantity in enormous quantities, is the timely production task of accomplishing, the calibrating of all must working overtime, add some points, and instrument frequently moves, and the disturbance hydrostatic evokes wave.According to Newton third law: acting force and reacting force produce simultaneously, interdependence; The wave action that evokes when instrument to around during cell wall, can reflex to instrument, through repeatedly stack; Situation is very complicated; Do not meet current meter hydrostatic vater tand inspection principle and instrument static demarcating principle, therefore, verification system is the legal precision of tool country metering not; Also promptly can not guarantee the current meter calibration accuracy, have following problem:

(1) systematic error: the current meter calibrating is a random measurement, has stochastic error and systematic error, when water fluctuation is big, regular strong, promptly forms systematic error, and mean square deviation can not reflect, also is difficult to represent calibration accuracy;

(2) judge the achievement standard: limit with technical target of the product; According to Mathematical Statistics Analysis; Three types of flase drops are arranged: a) in the limit certified products by the flase drop rising limit, according to special manufacturer statistics, sulculus (wide * length=2m * 85m) false drop rate be 10%～20%, vat (wide * length=5m * 200m) false drop rate is 5%～10%; This type flase drop can find in time that heavily inspection is corrected; B) certified products flase drop in the limit, maximum error can reach 8.3%; C) the unacceptable product flase drop is gone into limit.B) type and c) error, the quantity of type flase drop statistics of all having no way of, in the maintenance calibrating, once find to some extent;

(3) assignment deviation: different slots, same groove have certain difference in the calibrating achievement assignment of different time, and unfavorable flood control, irrigation, national economy water resource are utilized and the reorganization of hydrology flow;

(4) labour intensity: produce calibrating by batch, all must work overtime, add some points, work is tired, for accomplish the job rate on time; Worker's time of having a rest is short, even must on the calibrating car, have a dinner the neurolysis of working overtime the late into the night, high speed traveling; Stress, labour intensity is big, and car accident once takes place;

(5) production efficiency: calibrating speed is 0.04～4m/s, has 16 measuring points, after calibrating is accomplished at a high speed, after palpus waits " water body is tranquil ", carries out the low speed calibrating again, and production efficiency is low;

(6) work condition state: " water body is tranquil " is merely individual's sensation, lacks strict technical indicator and corresponding monitoring means;

(7) power consumption: calibrating car group weighs 0.3～11 ton, and power is 4～364 kilowatts, and energy consumption is big;

(8) operation cost: the calibrating measuring point is many, and road speed is high, and calibrating, hydrostatic time are long, and production efficiency is low, and management, running cost are big, the cost height.

3, the calibrating of current meter sampling both at home and abroad situation

(1) international standard ISO 2537-1974 " rotary cup and propeller current meter " 7.5 sampling calibratings, sampling observation is to be based upon one group of current meter to have on the consistent mechanical property basis, it is enough that sample size is wanted; 7.7 precision, calibrating curve measuring point should be normal distribution haply, and as the inspection of calibrating curve fitting goodness, the calibrating achievement should be explained the standard deviation of upper and lower limit and middle minimum two points, and degree of confidence is 95%.

(2) GB/T 11826 " rotating element current meter " of China's formulation in 2002, regulation: " in stable manufacturing process, frock is perfect, and crudy is reliable, and enterprise has quality assurance system, and has under the sufficient test basis, the calibrating of can sampling." owing to lack concrete grammar, fail so far to carry out.

China's current meter and performance calibration equipment thereof all have excellent precision at present, examine and determine by standard when strictness, and hydrostatic is good, can reach 0.10 grade; Current meter parts (promptly individual) precision is high, and high conformity for the sampling calibrating provides good basis, as long as the sampling observation method is correct, is guaranteed the hydrostatic operating mode in the calibrating, can guarantee overall accuracy; Yet China dealer always thinks that to the understanding of current meter calibration accuracy too " rigorous " seeing is believing, feels at ease by the frame calibrating, and precision is reliable.

(3) Britain, the U.S. are in the fifties in last century, and current meter is produced 2537 regulations according to ISO in batches, adopts the sampling calibration method to examine and determine.

British standard (BS) BS 3680 " open-channel flow measurement-rotor current meter " 11.5 sampling calibratings when instrument is made, strict control of material, size, error, and to guarantee the consistance of parts, the quantity of sampling calibrating is no less than 10.Based on a large amount of testing data analyses that Britain, the U.S. did, during 95% confidence level, current meter list frame with the limit of error of sampling calibrating is:

Flow velocity is respectively m/s:0.10,0.15,0.25,0.50;

Single frame gauging error is respectively %:5.0,2.5,2.0,1.0;

The sampling gauging error is respectively %:10,5.0,4.0,3.0.

The understanding that the U.S. examines and determine sampling: the standard deviation of sampling calibrating mainly is the calibrating stochastic error, the error that it causes much larger than manufacturing accuracy difference between the current meter; Its error character is at random with system; In the total error of flow measurement, have only a very little part, or indifference; The sampling calibrating is the same with requiring by its adaptation flow measurement of frame calibrating; Aborning, formulate strict standard and set up the quality control method calibrating of just can sampling.

4, sample population precision analysis

Theoretical according to mathematical statistics, the sample population precision is relevant with the individual precision and the methods of sampling; The methods of sampling can be divided into random sampling and nonrandom Quota Sampling.

(1) individual precision: precision is high for U.S.'s current meter part (promptly individual), and its part is assembled into glass rotor part that revolves of current meter transducing part, and then precision is not enough.Revolving a glass rotor part is to be dressed up by six beaker flask soldering group; Each beaker flask mutual alignment is difficult to accurately in three-dimensional coordinate; Also be difficult for measuring, more can not accurately examine and determine through tank, it is closely related to confirm to revolve the middle principal parameter b (being K) of glass rotor part characteristic parameter and formula (1); Therefore, the individual precision of its reflection instrument main performance is relatively poor; As through 2 of this product of the U.S. are revolved cup parts, carry out the performance calibrating at tank, deviation reaches 4.82% therebetween.

(2) assembly precision: current meter assembles the sensitivity relation of finished product to instrument performance, particularly the low-speed detection performance.Present special manufacturer both domestic and external all lacks necessary moment instrument accurately to be detected, and blows through personal mouth, only confirms low precision by rule of thumb; To the cleaning of precision instrument ball bearing, to roll in the gas and oil box through both hands and to wash, cleanliness are poor; Bearing moment is changeed through the quick bullet of finger, judge moment values with rotational time; To instrumental sensitivity is to blow with mouth, confirms by rule of thumb; Technology is owed standard, influences the apparatus working performance to a certain extent, promptly individual precision.

(3) methods of sampling: U.S.'s calibrating current meter is to adopt random sampling, because the problem that above-mentioned individual precision exists, so its overall accuracy is relatively poor.But by above-mentioned English, beautiful a large amount of testing data analyses of being done, by 95% degree of confidence, its error all can satisfy its current meter national standard technical requirement.

(4) tank calibrating: international standard ISO 2537 confirms that the current meter calibrating is a kind of random measurement, has stochastic error and systematic error.Go up according to this individual precision, and the problem of current meter large-lot production calibrating existence, can not guarantee individuality, overall accuracy by at present simple arbitrary sampling method.Like the different time of an instrument at same calibrating groove, or the different slots calibrating, its principal parameter b value deviation maximum can reach 5.73%.

Summary of the invention

Goal of the invention: in order to overcome the deficiency that exists in the prior art; The present invention provides a kind of performance sampling calibration method that is applicable to that current meter in enormous quantities is produced, and when guaranteeing calibration accuracy, enhances productivity, improves working conditions, streamlining management; Can practice thrift a large amount of human and material resources, time, electric power; To reduce operating cost, current meter calibration equation and low speed curve are adopted the subitem calibration method, and will examine and determine achievement and adopt average statistical as normalized form.

Technical scheme: for realizing above-mentioned purpose, the technical scheme that the present invention adopts is:

A kind of propeller type current meter performance sampling calibration method, this method comprises the steps:

(1) the rotating bearing component inner friction moment M of detection propeller type current meter judges whether M is up to standard;

(2) if M is not up to standard in the step (1), then rotating bearing component and ball bearing are cleaned, return step (1);

(3), then confirm the current meter speed V that runs up if M is up to standard in the step (1) ₀

(4) detect and to revolve the oar pitch angle alpha will, reject and be positioned at the oar that revolves that oar and appearance have defective that revolves that revolves beyond the oar helix angle critical field upper limit, the lower range, remainingly treat that sampling observation revolves oar;

(5) confirm group apart from Δ α, and will treat that apart from Δ α sampling observation revolves oar and be divided into the N group and revolve oar by group, the helix angle base value that the j group is revolved oar is α _j, 1≤j≤N wherein; In general, we can reject revolves the grouping that the oar number is less than 2 or 3, and the number of N is to have rejected these to revolve the later number of grouping that the oar number is less than 3;

(6) confirm that total number that statistical weight that j group revolves oar and this group revolve oar is identical, be designated as i _j

(7) will revolve the helix angle base value α of oar _jSubstitution experimental formula K _j=709.353tan α _j-577.121tan ²α _jIn, calculate j group propeller type current meter waterpower pitch K _jEmpirical value;

(8) all groups being revolved oar adopts nonrandom quota method, each group is revolved the inner p% that adopts method of random sampling to extract total quantity of oar revolves the oar sample as high speed; And it is installed on the rotating bearing component of propeller type current meter; Constitute the high speed model machine, the number that the j group is revolved the oar extraction is R _jIndividual, 0＜p≤100 wherein;

(9) extract q% in the high speed model machine from step (8), the q%p% that promptly revolves the oar total quantity is as the low speed model machine, and the total number of low speed model machine is R', wherein 0＜q≤100;

(10) carry out calibrating of high speed performance and low-speed performance calibrating:

(10-a) high speed performance calibrating

(a-1) by the sampling vertification regulation high speed model machine is descended water detection, according to formula V _Gjk=b _Gjkn _Gjk+ a _Gjk, calculate the calibrating achievement b that j organizes k high speed model machine _GjkIn the formula, V _GjkBe high speed district water velocity, b _GjkBe the high speed district propeller type current meter waterpower pitch of tank by the frame calibrating, n _GjkFor revolving oar rotating speed, a in the high speed district _GjkBe instrument constant, 1≤k≤R _j

(a-2) to the b of all high speed model machines _GjkK with correspondence _jCompare, calculation deviation and analyze reason, draw high speed performance verification result;

(10-b) low-speed performance calibrating

(b-1) by the sampling vertification regulation low speed model machine is descended water detection, according to standard revision value speed straight line formula V _Dk'=(b _Gk'-Δ b) n _Dk'+ (a _Gk'+ Δ a) is analyzed all fronts error of fitting E of k' frame low speed model machine _Dk'In the formula, V _{Dk '}Be low regime water velocity, b _Gk'(with the b in the step (a-1) _GjkIdentical) be the high speed district propeller type current meter waterpower pitch that tank is examined and determine by frame, n _Dk'For low regime is revolved oar rotating speed, a _Gk'(with a in the step (a-1) _GjkIdentical) be instrument constant, Δ b and Δ a are the revision value, 1≤k'≤R'.

Do not divide into groups during the detection of low speed model machine, six measuring points of every calibrating, through Δ b and Δ a match speed straight line formula, all fronts error of fitting is E _Dk'

(b-2) to the E of all low speed model machines _Dk'Carry out statistical study, draw the low-speed performance verification result.

Preferably, the calibrating of the high speed performance in the said step (10-a) is after the low-speed performance calibrating, to carry out or after natural hydrostatic surpasses 2h, carry out immediately following (disregard and calculate the words of time fully accurately); Low-speed performance calibrating in the said step (10-b) is after natural hydrostatic surpasses 15h, to carry out.

Preferably, in the said step (1), M scope up to standard is M≤3 scale values (moment instrument balancing point angles).Rotating bearing component is assembled by parts such as two cover ball bearings and turning axles, and ball bearing moment detects through bearing moment appearance checkout equipment, and its value up to standard is M'=0.4～0.5gcm; Because payload and the direction of bearing moment during with its detection is relevant, for singly overlapping ball bearing, loading is 100g; Loading direction is that axially moment values is 0.4～0.5gcm, and after dressing up complete machine; Because working load is for radially, the moment values difference is for fear of obscuring; Rotating bearing component inner friction moment M detects with propeller type current meter starting rotating speed checkout equipment, representes with its balancing point angular dimension, and this also is an instrument industry method for expressing commonly used.

Preferably, in the said step (5), group is apart from Δ α=0.01 °.

Preferably, in the said step (5), the scope of N is N=18～20.

Preferably, in the said step (8), p=30; In the said step (9), q=30.

Preferably, in the said step (10-a), if the calibrating achievement b of high speed model machine _GjkThan corresponding K _jBig by 0.8%, then the calibrating of high speed performance is carried out at the scene again.

Preferably, in the said step (10-b), if E _{Dk '}＞3%, then analyze b _Gk'And a _Gk'Value whether correct, if incorrectly then adopt correct b _Gk'And a _Gk'Value recomputates; If correct then the rotating bearing component of this low speed model machine is cleaned to M again up to standardly, and under hydrostatic condition, carry out the low speed calibrating again; a _Gk'A=0.008m/s compares with standard value, b _Gk'With corresponding K _jCompare.

Preferably, in the said step (10-a), b _GjkAverage statistical do

K _jPopulation mean do

b ₀With respect to K ₀Deviation be not more than 0.8%.

Preferably, said instrument constant a, revision value Δ b and Δ a adopt standard value: a=0.008m/s, Δ b=0.0094m, Δ a=0.0043m/s.

K _jValue in theory should be for through being α with a collection of helix angle _jRevolve oar and be assembled into model machine after, in reference current metre calibrating groove, hydrostatic condition is examined and determine down and the achievement of average statistical preferably, precision is higher, generally can pass through experimental formula K _j=709.577tan α _j-577.097tan ²α _jCalculate, adopted the computing method of experimental formula in this case; b _GjkValue be through the achievement of tank by frame calibrating, big because of producing in the calibrating water fluctuation in enormous quantities, b _GjkThe error of value maybe be bigger, even exceed standard.Suppose K in this case _jBe standard, and verify b in view of the above _Gjk

In this case: confirm the method and the equipment thereof of propeller type current meter waterpower pitch K value, can confirm the method and the equipment thereof of hydralic pitch K value of propeller hydrodynamometer with reference to Chinese patent 0.2137974.2; Standard revision value speed straight line formula can be with reference to the method for designing of Chinese patent 200810023206.0 rotary oar current meter norm edit value slow speed straight line formulas; The current meter speed V that runs up ₀Mensuration, can be with reference to Chinese patent 02263174.7 propeller type current meter starting rotating speed checkout equipment; The detection of Friction Moment of Ball Bearings can be used the Friction Moment of Ball Bearings measuring instrument with reference to Chinese patent 200720040306.5 propeller type current meters; The semi-automatic cleaning equipment of ball bearing can be with reference to Chinese patent 200720040307.X propeller type current meter ball bearing cleaning equipment and cleaning quality checkout equipment.

Beneficial effect: propeller type current meter performance sampling calibration method provided by the invention has advantages such as calibration accuracy height, calibrating is reliable, workload is few, labour intensity is low in producing calibrating in enormous quantities; Its technology operation science, standard, the National standard technical policy; This method is convenient to management simultaneously, and running cost is low, has science, society, economic benefit preferably; More as shown in table 1 with the benefit item by item of prior art:

Table 1 the present invention and the prior art odds ratio on projects

Embodiment

Do the relevant explanation explanation with regard to the theory of this case below, provide the piecemeal explanation of this case preferred version, provide the checking result in conjunction with instantiation.

Theoretical relevant explanation explanation

1. propeller type current meter waterpower pitch K

If instrument does not have inner frictional resistance, derive propeller type current meter equation of motion principal parameter with Hydrodynamics Theory:

K={[C _Y/(C _X-C _Y)tan ²α]+[C _X/(C _Y-C _X)]}πDtanα (2)

In the formula: C _XFor revolving oar skin resistance coefficient; C _YFor revolving paddle type structural drag coefficient; Tan α measures the section tangent of helix angle for revolving oar; The number of scraping is represented with B for revolving the oar resistance coefficient greatly; π Dtan α representes with H for revolving the oar geometrical pitch; So following formula is reduced to:

K=BH (3)

In the formula: B characterizes and to revolve oar and promote down at current, revolves in the oar rotating operation process obstruction to current, and the generation slip level and is revolved oar resistance coefficient C _X, C _YThe oar pitch angle alpha will is relevant with revolving; So it is slow partially than theoretical rotational speed to revolve the oar actual speed.Resistance coefficient B representes to revolve oar and revolves and turn around, and waterpower pitch is than the big several times of geometrical pitch; For the oar that revolves of approved product, π D is a definite value, C _X, C _YBe constant, change directly decision K value so revolve the oar pitch angle alpha will.

Testing under equipment, the hydrostatic condition preferably, formula (2) set up experimental formula:

K=709.353tanα-577.121tan ²α (4)

Visible by formula (4), revolve the oar pitch angle alpha will as long as record, can calculate the empirical value of K, in sampling, calibrating, can be for reference, analyze, with calibration accuracy and the overall accuracy of guaranteeing to sample.

2. low speed curve

The low speed curve is formula (a 1) straight line formula decurrence part, and its flexibility is decided by to revolve oar and accepts the current expulsive force, and the instrument inner frictional resistance; China's propeller type current meter performance has greatly improved at present, and declinate is merely 0.58 ° between the middle high, low speed straight line formula slope angle, fully available universal rotary oar current meter norm edit value slow speed straight line formula:

V ₁=(b-Δb)n ₁+(a+Δa) (5)

In the formula: V ₁Be the low regime water velocity, b is a high speed district propeller type current meter waterpower pitch, n ₁For low regime is revolved the oar rotating speed, Δ b and Δ a are the revision value, wherein Δ b and Δ a with revolve paddle structure, catchment area ω is relevant with instrument inner friction moment M; For approved product, change very for a short time, can think a constant; Up to standard when instrument rotating bearing component inner friction moment M detection, can adopt standard value; Following starting rotating speed V ₀, instrument constant a value also is-appearance.

3. instrument starting rotating speed V ₀

Starting rotating speed V ₀Be used to overcome the hydrodynamic(al) moment P of instrument inner friction moment M, according to fluid mechanics Ai Feier experimental formula, can try to achieve and act on the hydrodynamic(al) moment of revolving on the oar is P:

P=0.5ζρV ₀ ²ωR (6)

In the formula, ζ is for revolving oar resistance to water-flow coefficient; ρ is a water-mass density; V ₀Be water flow velocity; ω is for revolving the oar frontal projected area; R is for revolving the average radius of gyration of oar.At present the instrument manufacturing accuracy is high, and inner frictional resistance is little and stable, so ζ, ρ, ω, R can be considered constant.Through computing, abbreviation, can try to achieve starting rotating speed V ₀Formula:

V ₀=μ(M） ^0.5 (7)

The V of current meter tank calibrating at present ₀During value, because water fluctuation is big, do not meet current meter groove inspection principle and meter calibration principle, error is big, and according to statistics, maximum error can reach 62.3%; Can directly record starting rotating speed V through propeller type current meter starting rotating speed checkout equipment ₀Value, precision is better.

4. instrument constant C

The dimension of instrument constant C is [L], [T] ^-1, i.e. velocity head is used to overcome the kinetic energy of the inside and outside frictional resistance of instrument; Thereby, adopt the experiment statistics average by mathematic(al) theory of statistics, will have higher precision, and can avoid by water detection under the frame instrument, influenced by water fluctuation and produce the assignment error.

The piecemeal explanation of preferred version

This case sample mode: the high speed part, adopt nonrandom Quota Sampling to each big group, to the inner random sampling pattern that adopts of each group, extract and revolve the oar sample; The low speed part is examined the performance of revolving the oar rotating bearing component entirely; Method of random sampling is adopted in the speed straight line formula calibrating.Entire method roughly is divided into following several:

A. low-speed performance detects, and detects rotating bearing component inner friction moment M

A1) detect ball bearing moment M' through propeller type current meter with the Friction Moment of Ball Bearings measuring instrument, and judge according to M'=0.4～0.5gcm whether it is up to standard;

A2) adopt propeller type current meter ball bearing cleaning equipment to clean repeating step a1 to ball bearing not up to standard), until up to standard;

A3) detect rotating bearing component inner friction moment M through propeller type current meter starting rotating speed checkout equipment, and judge according to M≤3 scale values whether it is up to standard; If the M value is not up to standard, return step a1);

A4), confirm starting rotating speed V according to the M value to M value person up to standard ₀

A5) confirm that instrument constant a, revision value Δ b and Δ a adopt standard value: a=0.008m/s, Δ b=0.0094m, Δ a=0.0043m/s.

B. the high speed Performance Detection is used propeller type current meter blade helix angle checkout equipment to detect and is revolved the oar pitch angle alpha will

B1) detect: detect the size of pitch angle alpha will, confirm that its critical field is α=41 ° ± 0.15 °;

B2) divide into groups: divide into groups by the pitch angle alpha will size, group is apart from Δ α=0.01 °, group amount Z=3, group number N=13～16;

B3) reject: greater than 41.15 ° with less than 40.85 °, and reject with the oar that revolves that appearance has defective Z≤2 with pitch angle alpha will.

C. sampling

C1) all groups are revolved oar and adopt nonrandom quota method, each group revolved oar is inner to be adopted method of random sampling to extract 30% of total quantity to revolve the oar sample as high speed, and it is installed on the rotating bearing component of propeller type current meter, constitute the product complete machine;

C2) therefrom high speed performance is examined and determine 30% quantity that extracts wherein in the model machine and is examined and determine model machine as low-speed performance.

D. tank model machine calibrating

Strict GB/T 21699-2008 " the rotating element current meter calibration method in the straight line open channel " rules of pressing are examined and determine, and the calibrating arrangement of time is following:

The low-speed performance calibrating: natural hydrostatic one night (more than the 15h), the hydrostatic calibrating is claimed in mornig shift calibrating in second day;

High speed performance calibrating: carry out after the low-speed performance calibrating, each one class of morning and afternoon, more than the middle natural hydrostatic 2h, claim hydrostatic calibrating preferably.

E. on-the-spot calculating, analysis

E1) high speed performance calibrating: for b _GjkValue is greater than the corresponding calculated value K of formula (4) _jReach 0.5%, then should analyze reason, and resurvey, heavily examine;

E2) low-speed performance calibrating: greater than 2.0%, then should analyze reason for speed straight line formula (5) error of fitting, and resurvey, heavily examine;

E3) current meter performance gauging error is analyzed: the current meter calibration equipment is-the length tank groove width 3.5m * depth of water 1.5m * long 200m, groove bank both sides laying track; Current meter be installed in the calibrating car on, place the predetermined depth of water, the calibrating car with a series of speed V along rail travelling crane; Then current meter just produces linear relative movement with impounded body, and its speed is V (promptly examining and determine the speed of a motor vehicle), simultaneously current meter output speed n; According to a series of measuring points (V, n), high speed part (16 measuring points) but a match accepted way of doing sth (1); Low speed part (6 measuring points) but a match accepted way of doing sth (5); It is impounded body that the calibrating principle requires water body, and in fact, after calibrating several times, water fluctuation is big, with the standard input V of calibrating speed V as calibrating _BCertain deviation is just arranged, thus with the formula (1) of tank calibrating match, formula (5) just with standard speed V _BBetween have error.

F. data statistics analyse

F1) according to formula (4) calculating K _jValue, and by each group instrument quantity weighting, statistics population mean K ₀

F2) b that examines and determine according to the tank sampling _GjkValue is calculated and is respectively organized b _GjkWeighted mean, and statistics overall average b ₀As normalized form;

F3) calculate b ₀With K ₀Between deviation E, like E≤0.3%, the checking b ₀Normalized form is correct, and has very high calibration accuracy;

F4) calculate each instrument groove inspection b _GjkValue and its corresponding K _jThe deviation of value is to find flase drop;

F5) calibration equation a value, the average statistical conduct is to normalized form a ₀The checking of value;

F6) standard revision value speed straight line formula calculates average error and starting rotating speed V completely ₀Error.

Case verification

This example detects, samples to examine and determine to a collection of totally 86 propeller type current meter tanks and tests; Full inspection is adopted in this sampling calibrating experiment, so that analyze the gauging error source, helps to explain the necessity and the feasibility of sampling calibrating.The current meter mechanical property detects carries out under the measuring room condition, and it is high that it detects the achievement precision, stable, reliable, and repeats easily; The calibrating of current meter performance is carried out in straight line open channel water body, and its operating mode is complicated, and is difficult to monitoring.For this reason, the sampling calibrating procedure is preferably arranged double shift, to reach hydrostatic condition preferably; But be the completion of speed production task, this experiment is arranged by Fourth Shift's system of routine, because the water fluctuation influence is bigger, achievement is not good enough.

The achievement analysis of facing detection, sampling and the calibrating of this experiment is down explained, proves the feasibility and the necessity of current meter production in enormous quantities calibrating employing sampling calibration method simultaneously.

One, low-speed performance detects, examines and determine

(1) the instrument low-speed performance detects

1) detects ball bearing moment M' through propeller type current meter with the Friction Moment of Ball Bearings measuring instrument, and judge according to product standard M'=0.4～0.5gcm whether it is up to standard;

2) adopt propeller type current meter ball bearing cleaning equipment to clean repeating step a1 to ball bearing not up to standard), until up to standard;

3) detect rotating bearing component inner friction moment M through propeller type current meter starting rotating speed checkout equipment, and judge according to M≤3 scale values whether it is up to standard; If the M value is not up to standard, return step a1);

4), confirm starting rotating speed V according to the M value to M' value and M value person all up to standard ₀

5) instrument calibration equation constant all adopts standard value: high speed straight line formula constant a=0.008m/s; Low speed standard revision value straight line formula Δ a=0.0043m/s, Δ b=0.0094m.

(2) instrument low-speed performance calibrating

The hydrostatic calibrating, natural hydrostatic one night (more than the 15h), first shift calibrating the next morning:

1) instrument starting rotating speed V ₀=0.03～0.04m/s, the product technology standard is 0.05m/s;

2) standard revision value speed straight line formula all fronts error of fitting E: average out to 0.79%, minimum is 0.40%, is 1.99% to the maximum, much smaller than product technology standard 3%, GB 5%;

The calibrating of non-hydrostatic, i.e. second～Fourth Shift calibrating because water fluctuation is big, big to the influence of low speed calibrating achievement, error is big, visiblely has the sufficient time hydrostatic because sampling instrument quantity is few, can guarantee to examine and determine the achievement precision, and is significant to reality;

3) calibrating performance analysis: water fluctuation is to instrument starting rotating speed V ₀Big with the influence of low speed curve, like table 2, shown in 3.

Table 2 have, under the no hydrostatic condition, propeller type current meter calibrating achievement error character value statistical form

Table 3 have, under the no hydrostatic condition, propeller type current meter low speed curve calibrating achievement comparison sheet

(3) the low speed curve error is analyzed

In the table 3, № 09245 instrument is that water fluctuation is big, has bigger systematic error: 8.01% in last calibrating at night; Curve is that manual work is drawn along the measuring point rule by rule of thumb at present; And big systematic error is regular strong, and line smoothing, precision height are seen in the surface, has caused big problem of present low speed calibrating also; And the product technology standard lacks corresponding systematic error technical indicator, and method of discrimination.In fact, during rotating bearing component inner friction moment M≤3 lattice, the instrument operation is very stable; Under M value situation up to standard; The instrument of extraction 9% carries out the hydrostatic calibrating, adopts standard revision value speed straight line formula, promptly can reach very high precision; Have favorable economic benefit, and produce, use all very convenient.At present, hydrographic survey is all used the low speed curve map under the wind and rain condition in the open air, and it looks into and read, calculates all inconvenient, and error is big.

Two, high speed Performance Detection, calibrating

1) detect and sampling:

(1) detect: use propeller type current meter blade helix angle checkout equipment to detect and revolve the oar pitch angle alpha will, its critical field is α=41 ° ± 0.15 °;

(2) arrange: arrange from small to large by pitch angle alpha will;

(3) reject: greater than 41.15 ° with less than 40.85 °, and group amount Z≤2 reject with the oar that revolves that appearance has defective with pitch angle alpha will, remainingly treat that sampling observation revolves oar;

(4) divide into groups: ° will treat apart from Δ α=0.01 that by group sampling observation revolves oar and be divided into the N=14 group, the helix angle base value that each group is revolved oar is α j, wherein 1≤j≤N; This N component group is to have rejected to revolve the oar number and be less than number after 3 the grouping (this is because the very few group of number is representative poor);

(5) flexible strategy: confirm that total number that statistical weight that j group revolves oar and this group revolve oar is identical, be designated as i _j

(6) calculate: α _jSubstitution calibration equation K _j=709.353tan α _j-577.121tan ²α _jIn, calculate j group propeller type current meter waterpower pitch K _jEmpirical value;

(7) sampling: revolve oar quantity by every group and confirm sampling number; At first revolve oar quantity t divided by 3 with every group; Quotient decimal place to t/3 is gone into principle with 3 houses 7, revolves oar with every group and is divided into some basic group, in each is organized basically, extracts one again and revolves oar (example: if t=4; Then t/3=4/3=1.3 is divided into a basic group; If t=5, then t/3=5/3=1.7 is divided into two basic groups; If t=7, then t/3=7/3=2.3 is divided into two basic groups; If t=8, then t/3=8/3=2.7 is divided into three basic groups; ), extract 23 altogether and revolve oar.

2) high speed performance calibrating:

(1) calibrating: by the sampling vertification regulation high speed model machine is descended water detection, according to V _Gjk=b _Gjkn _Gjk+ a _Gjk, calculate the calibrating achievement b that j organizes k frame instrument _GjkAnd a _Gjk

(2) deviation: calculate j organize k frame instrument b _GjkK with correspondence _jDeviation δ _Gjk

(3) statistics: calculate totally 23 model machines 14 groups times, represent the K of overall 69 the instrument high speed samples of this batch through weighting _jPopulation mean K ₀And b _GjkAssembly average b ₀

(4) analyze

(4-a) visible by table 4, for 23 model machines of 69 model machine simulated sampling calibratings, b _GjkMean value be 195.1mm, K _jMean value be 195.04mm; To all 86 instruments of this batch, the mean value of b is 195.0mm, and the mean value of K is 194.99mm; In the practicality, adopt three figure places by the GB regulation, promptly 195mm is then all identical;

(4-b) to standard value deviation average out to: δ _b=0.75%, δ _k=0.14%;

(4-c) the maximum error scope is: tank is-1.03%～1.49% by frame calibrating b, totally 6, accounts for sum 7%; Calculated value K is 0～0.85%, adopts the sampling observation mode, and big error will be avoided;

(4-d) above-mentioned flase drop instrument can be analyzed, heavily examine in the scene, thereby the flase drop that can avoid conventional calibrating to be difficult to avoid.

Three, flase drop analysis

Visible by subordinate list 1, the tank calibrating has the b of 6 instruments _GjkCorresponding relatively K _jDeviate δ _jGreater than 1%.Detect, arbitrate because of present country still has STANDARD MEASURING APPARATUS FOR, we are the movement mechanism of first analytical instrument normally, arbitrates through the method afford of calibrating again again.

(1) movement mechanism analysis

Visible from subordinate list 1, these 4 instruments respectively 4 not on the same group in, the error of other instruments is all very little in its respective sets, on average is respectively 0.3%～0.54%, obviously deviation greater than 1% instrument be in calibrating, receive the water fluctuation influence comparatively strong due to.

(2) detect the α value again with revolving oar helix angle checkout equipment, recomputate deviation average out to E by formula (4) _K2=0.33%, as shown in table 4 to the achievement that the flase drop instrument is identified again.

(3) calibrating again

1) earlier in the calibrating of A groove, its achievement is b3,4 instrumental bias average out to E _B3=5.08%, up 5.73%;

2) examine and determine again at former inspection B groove, its achievement is b2 again, and 4 instrumental biass are on average from the E first time _B1=1.26%, reduce to E _B2=0.32%;

By above revolve the analysis of oar operation mechanism and resurvey, rerun and heavily inspection show that these 4 instruments calibrating achievements are flase drop.

The flase drop instrument is examined and determine outcome table again in the calibrating of table 4 propeller type current meter tank

The above only is a preferred implementation of the present invention; Be noted that for those skilled in the art; Under the prerequisite that does not break away from the principle of the invention, can also make some improvement and retouching, these improvement and retouching also should be regarded as protection scope of the present invention.

Subordinate list 1 propeller type current meter sampling standard verification formula calculating achievement table

Explain:

1. this batch instrument is totally 86, at first with revolving oar helix angle checkout equipment by the angle-offset method measuring principle, detects two blade standard radius R sections and revolves oar helix angle difference: △ Z1, △ Z2; Calculate spiral shell angular difference value: △ a1, △ a2, average helix angle a calculates and revolves oar geometrical pitch H; According to testing under the hydrostatic condition preferably; Confirm to revolve oar resistance coefficient B, calculate waterpower pitch K value, with formula (4): K=709.353tana-557.121tan ²A, checking computations, mean deviation is 0.00033%.

2. hypothesis is with in the experiment down of hydrostatic condition preferably, and the K value through theoretical analysis, calculating is a standard, b value and its deviation δ that the calculating tank is examined and determine.

3. deviation δ=1.07%～1.51% is totally 7, analyzes 11, No. 99162 instrumental bias δ=1.51% of sequence number №; This group № 9～12 totally 4 instruments, revolve vane angle degree: a=41.0219 ° identical, 3 instrument tanks calibrating b deviations are 0.03%～0.49%; Obviously, deviation 1.51% is a flase drop.Other deviation is greater than also identical in 1% 7 groups.

4. for checking is because the flase drop of the big generation of water fluctuation revolves oar helix angle a to 4 instruments to detect again, calculate, and instrument is examined and determine again with the upper deviation, all obtain proof, see text table 4 for details.

5. current meter calibration equation principal parameter b (K) value overall average is: b=195.0mm; K=194.99mm.Both are consistent.In view of the above, can adopt normalized form: b=195.0mm.

6. match system deviation :+0.01%, system deviation frequency :+49.8%.Show that match is correct, and have very precision.

Explain:

1. this batch simulation sampling observation instrument is totally 86, divides into groups totally 14 groups by revolving oar helix angle a=0.01 degree.

With a value have only 1,2 revolve oar totally 16 removals, substantial amt is 70.

3. every group is 3～8, by every group of quantity Quota Sampling: 3, take out 1 for 4, take out 2 for 5,7, take out 3 for 8.

4. before the instrument calibrating, every revolves oar by a, and with experimental formula (4) calculating K value, instrument all descends water detection, confirms the b value.

5. sample mode is maximum with respect to the error of K value by the b value, shows that the sampling condition is the poorest.Actual sampling is at random.

6. average statistical: groove inspection: b=195.1mm, calculate: K=195.04mm.The value of settling the standard: b ₀=K ₀=195mm.To standard value deviation: b is 0.31%～1.49%, average, 0.75%; K is 0～0.35%, and is average, 0.14%.

7. groove inspection error is more greatly because by 4 classes of traditional system calibratings, and water fluctuation causes greatly, other analysiss of putting on record, and the inspection of laying equal stress on is arbitrated.

8. large quantities of sampling calibratings will be adopted 2 classes of systems, and the sampling observation instrument is 30%, and hydrostatic condition is good, can obtain better achievement.

Subordinate list 3 rotary oar current meter norm edit value slow speed straight line formula match achievement △ α=0.0043m/s; △ b=0.0094m

Explain:

A kind of precision bearing moment instrument that generally uses in the world, its principle is: use gas velocity V ₀The airflow moment that produces overcomes ball bearing inner friction moment M, accurately confirms bearing friction moment M in view of the above.This patent is used this institute propeller type current meter starting rotating speed checkout equipment patent of principle development in view of the above, can accurately she confirm instrument starting rotating speed V ₀Value.Last illness that has not attacked the vital organs of the human body is bright as long as examine and determine under hydrostatic condition by this patent equipment 9.0% instrument of sampling, and just can guarantee instrument starting rotating speed V ₀Value, and low-speed performance.

Last table starting rotating speed V ₀Error: 5.04%～14.31%, totally 32, accounting for sum 31.4% all is the achievement of under the 2nd～4 class of big situation of water fluctuation, examining and determine.

Subordinate list 4 usefulness normalized form checking computations experimental formula calculating K values and tank calibrating b error

Explain:

1. it is average to go up table statistics instrument calibration equation principal parameter: K=194.99, b=19.50mm, can adopt b in view of the above ₀=195.0mm is as normalized form.In the practical application, adopt three figure places: i.e. normalized form b by the hydrologic survey requirement ₀=195mm; Formula mean square deviation m≤1.5%, conformance with standard requirement fully.

2. analyze each frame instrument assignment deviation:

A. experimental formula calculating K value, luffing: 194.08～196.65mm, deviation :-0.01%～+ 0.85%, mean deviation 0.18%;

B. the current meter tank is examined and determine the b value, luffing: 192.9～197.9mm, and deviation: 0.00%～+ 1.49%, mean deviation 0.44%.

3. employing normalized form: b ₀=195mm.Each frame instrumental bias δ >=1%: with the K value that experimental formula is calculated, deviation is all less than 0.85%;

The b value of current meter tank calibrating ,-1.03%～+ 1.49%, totally 6,

Account for sum 8.82%.

4. by present case sampling observation principle: 16 of the representative difference in removal group amount Z≤2 revolve oar, and its error is 0.29%～0.85%, remaining meet that sampling observation requires revolve totally 70 on oar, after it is mounted to complete machine, adopt its error of normalized form to be merely 0.12%～0.35%.

5. current meter calibrating achievement and calibration equipment, characteristic, factors such as cell body size are relevant, present case be at present whole nation specialty calibrating groove preferably it-, its calibrating achievement still has error as above, and for the calibrating as the arbitration property, deviation reaches 5.73% unexpectedly.

6. divide folding to show by present case experiment achievement, this patent is applied and can be guaranteed current meter calibrating achievement precision, be not for a long time people generally believe: every instrument must all will descend water detection, and " soon for for real " just can guarantee to examine and determine the precision of salty fruit.

7. produce in enormous quantities in the calibrating, water fluctuation is big, violates current meter tank calibrating principle and meter calibration principle, can't guarantee to examine and determine the achievement precision, and this patent aims at exactly and addresses this problem and develop.

Claims

1. propeller type current meter performance sampling calibration method, it is characterized in that: this method comprises the steps:

(2) if M is not up to standard in the step (1), then rotating bearing component is cleaned, return step (1);

(5) confirm group apart from Δ α, and will treat that apart from Δ α sampling observation revolves oar and divide into groups by group, remove the group of group amount Z≤2, remaining N group is revolved oar, and the helix angle base value that the j group is revolved oar is α _j, 1≤j≤N wherein;

(10-a) high speed performance calibrating

(a-1) by the sampling vertification regulation high speed model machine is descended water detection, according to formula V _Gjk=b _Gjkn _Gjk+ a _Gjk, calculate the calibrating achievement b that j organizes k high speed model machine _Gjk, in the formula, V _GjkBe high speed district water velocity, b _GjkBe the high speed district propeller type current meter waterpower pitch of tank by the frame calibrating, n _GjkFor revolving oar rotating speed, a in the high speed district _GjkBe instrument constant, 1≤k≤R _j

(10-b) low-speed performance calibrating

(b-1) by the sampling vertification regulation low speed model machine is descended water detection, according to standard revision value speed straight line formula V _Dk'=(b _Gk'-Δ b) n _Dk'+ (a _Gk'+ Δ a) is analyzed all fronts error of fitting E of k' low speed model machine _Dk', in the formula, V _Dk'Be low regime water velocity, b _Gk'Be the high speed district propeller type current meter waterpower pitch of tank by the frame calibrating, n _Dk'For low regime is revolved oar rotating speed, a _Gk'Be instrument constant, Δ b and Δ a are the revision value, 1≤k'≤R';

2. propeller type current meter performance sampling calibration method according to claim 1 is characterized in that: the high speed performance calibrating in the said step (10-a) is after the low-speed performance calibrating, to carry out or after natural hydrostatic surpasses 2h, carry out; Low-speed performance calibrating in the said step (10-b) is after natural hydrostatic surpasses 15h, to carry out.

3. propeller type current meter performance sampling calibration method according to claim 1, it is characterized in that: in the said step (1), M scope up to standard is M≤3 scale values.

4. propeller type current meter performance according to claim 1 sampling calibration method is characterized in that: in the said step (5), group is apart from Δ α=0.01 °.

5. propeller type current meter performance sampling calibration method according to claim 1, it is characterized in that: in the said step (5), the scope of N is N=18～20.

6. propeller type current meter performance sampling calibration method according to claim 1 is characterized in that: in the said step (8), and p=30; In the said step (9), q=30.

7. propeller type current meter performance sampling calibration method according to claim 1 is characterized in that: in the said step (10-a), if the calibrating achievement b of high speed model machine _GjkValue than corresponding K _jCalculated value exceed 0.8%, then high speed performance calibrating is carried out at the scene again.

8. propeller type current meter performance sampling calibration method according to claim 1 is characterized in that: in the said step (10-b), if speed straight line formula all fronts error of fitting E _Dk'＞3%, then analyze b _Gk'And a _Gk'Value whether correct, if incorrectly then adopt correct b _Gk'And a _Gk'Value recomputates; If correct then the rotating bearing component of this low speed model machine is cleaned to M again up to standardly, and under hydrostatic condition, carry out the low speed calibrating again.

9. propeller type current meter performance sampling calibration method according to claim 1 is characterized in that: in the said step (10-a), and b _GjkAverage statistical do K _jAverage statistical do

b ₀With respect to K ₀Deviation be not more than 0.8%.

10. propeller type current meter performance sampling calibration method according to claim 1, it is characterized in that: said instrument constant a, revision value Δ b and Δ a adopt standard value: a=0.008m/s, Δ b=0.0094m, Δ a=0.0043m/s.