Background technology
Accurately the core technology of irrigating is to develop the equipment of irrigating the different water yields according to the block-shaped needs of crop or ground at diverse location, except the equipment that on irrigation sprinkler, is equipped with GPS (GPS) and Geographic Information System (GIS), comprise that mainly variable executes water Irrigation shower head, controller and variable delivery pump.Wherein the most key equipment should belong to variable and execute the true Irrigation shower head of crystal, variable sprayer can be regulated flow and range automatically according to the block-shaped needs of crop and ground, it is controlled realize to spray territory and sprinkling amount, spray and phenomenon such as sprinkling out-of-bounds occur respraying, leaking, with the conserve water resource with avoiding.
The research of variable sprayer and application are existing for many years, there is the variable sprayer of many types report and patented claim are also arranged in succession more, as China Patent No. is 01265799.9,00257672.4,00215392.0,03218591,96212526.1,98232884.2,03114528.0,03218591.x, U.S. Patent number is 1637413,2582158,2780488,3952954,3261552,4198001,6079637,4277029, British Patent No. is 2094181A, 2094181A, european patent number be among 0395230A1 etc. disclosed shower nozzle can realize spraying the territory and the sprinkling amount controlled, its implementation substantially all is to adopt certain sprinkling territory and the controlled device of sprinkling amount on the basis of former circular sprinkling territory nozzle structure, realizes variable spray.The article that the present inventor delivers on publications such as Transactions of the Chinese Society of Agricultural Engineering, agricultural mechanical journal " profiling is sprayed variable and executed the true irrigation technique progress of crystal " (2004 the 1st phases) and " the non-circular sprinkling domain variable is executed the true Irrigation shower head Review Study of crystal " has been done comparatively detailed argumentation to structure, principle of work and the performance characteristics of domestic and international variable sprayer in (2004 the 5th phases).
The actual sprinkling territory shape of variable sprayer is the key factor of variation sprinkler performance.With the square spray field variable sprayer is example, and the shape that the square spray field shower nozzle in the practice sprays out is not entirely square, may between circular and square between.But in above-mentioned disclosed patent, do not relate to variable sprayer is sprayed metric parameter and the Measurement Study thereof that the territory shape realizes precision.
Summary of the invention
Spray defective or the deficiency that regulation and control performance measurement aspect, territory exists at above-mentioned variable sprayer, the objective of the invention is to, a kind of assay method of square coefficient of square spray domain variable spray head is provided.
To achieve these goals, the present invention takes following technical scheme:
A kind of assay method of square coefficient of square spray domain variable spray head is characterized in that, by increasing the range regulator, the shape in the sprinkling territory of square spray field variable sprayer is changed into square from original circle.Square square after changing fully for meeting n in the former circle, the theoretical range on the square zenith directions of n is the range of former circular shower nozzle, the theoretical range on the mid point direction of the square sideline of n should be former circular sprinkler pattern range
Doubly, be the shortest range of theory of n square spray field variable sprayer, its theoretical variable quantity is the former circular territory sprinkler pattern range that sprays

Doubly.In the shower nozzle spray test, measure the variable quantity of measured sprinkler range on the sideline mid point direction of actual n square spray field variable sprayer product by the radial arrangement rain gage bucket.Ratio with the variable quantity variable quantity theoretical with it of measured sprinkler range defines block coefficient, sprays the territory and changes square change degree into from circle as weighing.Therefore, the circular block coefficient that sprays the territory shower nozzle is 0% (promptly not changing fully), and the block coefficient of n square spray field variable sprayer is 100% (promptly changing fully) fully.Usually, the block coefficient of square spray field variable sprayer product is between 0~100%, and measured sprinkler range variable quantity variable quantity theoretical with it is approaching more on the mid point direction of sideline, and the degree from circle to square change is big more, the block coefficient value is also big more, shows approaching more square.
The square coefficient of square spray domain variable spray head that method of the present invention determines can clearly be described the shape of spraying the territory and change into square change degree from original circle, outstanding square spray field and the circular contrast effect that sprays the territory improve practicality, operability and the intuitive of block coefficient in application in practice.
Embodiment
Referring to Fig. 1, the present invention is a kind of assay method of square coefficient of square spray domain variable spray head, and the step of this method comprises:
Step 1: radial arrangement rain gage bucket
With the nozzle position is central point, radial arrangement rain gage bucket on the line direction of square spray field variable sprayer sideline mid point and central point.N square spray field variable sprayer need be arranged n bar radial line, and Fig. 1 is square spray domain variable spray head, therefore arranges four radial line at OG, OH, OI and OJ four direction.
Step 2: measure the shortest range of shower nozzle
Carry out spray test, read the water depth value of the rain gage bucket of radial arrangement on the shortest range direction after the been sprayed, determine the range of variable sprayer according to national standard.The shortest range of n square spray field variable sprayer is respectively r
i(i=1,2 ... n).For square spray domain variable spray head among Fig. 1, n=4.
Step 3: calculate the most short-range mean value
For n square spray field variable sprayer, the most short-range mean value of n bar radial line upper nozzle actual measurement is
R wherein
iIt is the actual measurement range of i bar radial line direction upper nozzle.The most short-range mean value of square spray domain variable spray head actual measurement is the mean value of range on OG, OH, OI and the OJ four direction among Fig. 1, promptly
Step 4: determine the shortest range of theory
The shortest range of theory of variable sprayer is the distance of sideline mid point to shower nozzle.For n square spray field variable sprayer, its theoretical bee-line should be
The theoretical bee-line of the square spray domain variable spray head among Fig. 1 is
Step 5: determine theoretical and actual measurement range variable quantity
The range variable quantity of variable sprayer is divided into actual measurement variable quantity and theoretical variable quantity.Theoretical range variable quantity is former circular territory sprinkler pattern range and the most short-range difference of theory of spraying, and uses Δ r
0Expression.Actual measurement range variable quantity is former circular territory sprinkler pattern range and the difference of surveying the shortest range mean value of spraying, and r represents with Δ.Actual measurement range variable quantity between 0 and theoretical range variable quantity between, i.e. 0≤Δ r≤Δ r
0For n square spray field variable sprayer, theoretical range variable quantity is
Actual measurement range variable quantity
Its value exists
In the scope.The theoretical range variable quantity of the square spray domain variable spray head of Fig. 1 is
Actual measurement range variable quantity
Its value exists
In the scope.
Step 6: calculate block coefficient
The definition block coefficient is represented with η for the ratio of actual measurement range variable quantity and theoretical range variable quantity.For n square spray field variable sprayer, block coefficient
The shortest range measured value of shower nozzle that substitution is initial:
By following formula as can be known, work as r
i(i=1,2 ... n)=and during R, η=0, it be circular that the territory is sprayed in expression, promptly sprays territory not change fully; When
The time, η=100%, it is square that the territory is sprayed in expression, promptly sprays the territory and changes fully.Usually, the block coefficient of square spray field variable sprayer is between 0~100%, and the degree from circle to square change is big more, and the block coefficient value is big more, shows approaching more square.
The block coefficient of square spray domain variable spray head shown in Figure 1 can calculate with following formula:
Fig. 2 and Fig. 3 are respectively the three-dimensional water distribution figure of square spray domain variable spray head and the isogram of the invention process example, with the realizability and the accuracy of proof the inventive method.Its measuring object is the square spray domain variable spray head that repacking forms on former rain bird 30PSH nozzle structure basis that the present inventor researches and develops, this shower nozzle maximum range, the range R=18 rice of promptly former rain bird 30PSH shower nozzle.Table 1 is to adopt radially water distribution data of following four of measuring of rain gage bucket arrangement described in the assay method of the present invention, and rain gage bucket is by equidistantly laying every 90 degree, and working pressure is 0.3Mpa.
Water distribution data on the shortest range direction of the square variable sprayer of table 1
Determine that the shortest range of four direction upper nozzle all is 13 meters, substitution formula (2), block coefficient η=94.8% that must this variable sprayer.The three-dimensional water distribution figure of edition with parallel text example measured data and isogram as can be known, assay method of the present invention can determine the block coefficient of square spray field variable sprayer exactly.