1 Is the amount of watering as large as possible?
In the process of buying watering vehicles and users, users always hope that the amount of water to be sprayed is better, but in practical applications, the idle watering distance is short, the frequency of water addition is increased, the fuel consumption for idle driving and reentry operations is increased, and the expenditure for funds is increased. Poor social economy.
The main role of sprinkler operations is to reduce heat, cool dust, and clean air. If the amount of water sprayed is too large, partial water will accumulate due to the unevenness of the ground. A part of the water will flow along the road into the sewer, causing water resources and economical waste. If there is much mud on the ground, muddy mud will easily form. Due to the adhesive tape of the vehicle tires, As a result of the extension of ground pollution, after the ground is dry, a larger area of ​​dust is formed and polluted.
The resulting topic is that the wine operation should be carried out after the floor has been cleaned, and if the heavily polluted ground is sprinkling water, it is more difficult to clean, and the amount of water sprayed is not good.
(The sprinklers manufactured by Cheng Li can freely adjust the amount of water. In addition, the high-pressure device of Cheng Li's sprinkler can clean the front of the road and sprinkle it with water after spraying. This will not allow water and miscellaneous As things get mixed up, sanitation workers only need to clean the two sides of the road.)
2 Quantitative analysis of watering volume
In view of the above, the sprinkling of water by the sprinkler is not good, and the small amount of sprinkling does not have a significant effect.
So, how to determine the practical and economic sprinkler sprinkler? Now take Dongfeng EQ1092 (or EQ1092F19DJ) type 5t sprinkler as an example for calculation and analysis.
Performance parameters:
Engine speed range ne 1200-3000 r/min
Transmission speed ratio ik
One file i1 7.31
Second gear i2 4.31
Third gear i3 2.45
Power take-off ratio iT l.373
Pump
Rated speed nP 1450 r/min
Flow rate Q 60 m3/h
Head H 60 m
Shaft power N 16 kw
Calculated according to the rated speed of the pump:
Engine speed n 1991 r/min
One speed of travel Y1 7.22 km/h
Second gear speed Y2 12.24 km/h
Third gear speed Y3 21.53 km/h
The technical speed of the sprinkler truck is 5-20km/h and the actual applications are all in the l-3 range. Therefore, the amount of drinks at high speed is not calculated.
Under the rated speed of the pump, full load 5t, sprinkler operation time t:
t=5min
Under the rated speed of the pump, the full-scale sprinkler sprinkler operation distance S:
One file S1=602m
Second gear S2=1020m
Third gear S3 = 1794m
Under the rated speed of the pump, full load sprinkler width 14m, its average
Sprinkler q: One file q=0.59L/m2
Second gear q=0.35L/m2
Third gear q=0.20L/m2
At the rated speed of the pump, the amount of water sprayed is only proportional to the flow of the pump.
The average amount of sprinkled water in one file is the smallest.
Table 1 Comparison of pump flow rate and watering volume in first gear
Pump flow (m3/h) | Watering volume (L/m2) |
40 | 0.39 |
50 | 0.49 |
60 | 0.59 |
80 | 0.79 |
100 | 0.98 |
203 | 2 |
The average watering by the third grade is the smallest, and the accounting comparison is shown in Table 2.
Table 2 Comparison of Pump Flow and Sprinkling at Third Stage
Pump flow (m3/h) | Watering volume (L/m2) |
40 | 0.13 |
50 | 0.17 |
60 | 0.20 |
80 | 0.27 |
100 | 0.33 |
203 | 0.68 |
3 Analysis of watering standards
According to the requirements of QC/T2911-93 Technical Specifications for Sprinklers, when the sprinkler width is ≥14m, the amount of water sprayed is 0.2-2L/m2, that is, the water column height per unit area is 0.2-2mm2. It has been calculated previously that when the watering volume is 2L/m2 and the sprinkler width is 14m, the pump flow rate is as high as 203m3/h. Such a high flow rate is not present at home or abroad. Obviously, the standard watering volume is 2L/m2 maximum. Too high is not realistic. If the maximum amount of watering is positioned at 1L/m2, then the water pump flow rate equivalent to 100m3/h can achieve such a requirement, but it is not economical, and if it is actually applied, a 1mm high water is formed in the urban hardening road sprinkling area. In the area, these waters cannot be attracted or evaporate all the time, and the formation of surface water will cause chaos, which will cause waste of water resources.
Therefore, it is necessary to formulate scientific and reasonable technical requirements in light of actual application conditions.
4Why does a sprinkler user always ask for more watering?
The user uses a flow rate of 80m3/h for watering, but he still needs to spray more water. What are the reasons? Through understanding, the number of sprinklers in various cities in China is insufficient. Most sprinklers also need to take care of greening and watering tasks. Due to lack of financial resources, even if water is sprayed on main lines, the amount of water sprayed is also required to be larger, and it is hoped that it will remain for quite a long time. It seems to have just spilled water, and this kind of sprinkler operation has also become an adornment to welcome the guests and leaders. Due to lack of financial resources,
Sprinklers often stop in the hot summer months and cannot work effectively. This situation must change, and it really makes the wine carts play a role in purifying and beautifying the city.
5 The opinion of increasing the width of watering should be supported
At present, the sprinkler width of domestic sprinklers is generally adjusted to 14-16m. However, with the widening of roads and the development of expressways, the requirement for sprinkler widths of more than 20m is a frequent voice heard by manufacturers. If only the lift of the pump is increased, the water is increased. The pressure to increase the width of watering will not only increase the cost, but also increase the user's fuel consumption. The social economy is not good.
The simple and practical way is to increase the height of the rear nozzle from the ground. According to the principle of flat-throwing motion, if the flow rate is constant, the distance of its ejection is proportional to the square root of the height from the ground. If the nozzle height is 0.7m, the double nozzle spray width is 14m; if the nozzle height is l. For 4m, the double nozzle sprinkling width can reach 19.8m; if the nozzle height is 2.8m, the double nozzle sprinkling width can reach 28m, but the sprinkling quantity at this time is also inversely proportional to the drop.
Raising the height of the nozzle from the ground not only can effectively increase the width of the sprinkler, but also has a more obvious effect on cooling, dust squeezing, and purifying the air. This practical and new type of elevated nozzle device will certainly be welcomed by the society.
6 Sprinkler System Pressure Estimation
According to the principle of fluid mechanics, head loss includes loss of local head due to head loss along the way. The head loss along the way is proportional to the square of the tube length and flow velocity, and the local head loss is proportional to the square of the flow velocity. Therefore, choosing the right pipe diameter to adjust the flow rate is the key to reducing the head loss.
After the flow rate is determined, refer to Table 3 to select the pipe diameter.
Table 3 Pipe Diameter and Maximum Flow Limit Table
Maximum flow (L/S) | Pipe diameter (mm) | The maximum flow rate (m/s) |
1 | 25 | 2.4 |
2.5 | 38 | 1.69 |
4.17 | 50 | 2.01 |
6.67 | 65 | 2.12 |
10.0 | 75 | 2.26 |
18.4 | 100 | 2.33 |
30.0 | 125 | 2.44 |
43.0 | 150 | 2.45 |
Remarks: Above this limit, the head loss is significantly increased
Straight pipe head loss can be found in Table 4
Table 4 100m straight pipe head loss table m
Pipe diameter (mm) | |||||||||||||
1 | 2 | 4 | 6 | 8 | 10 | 15 | 20 | 25 | 30 | 40 | 50 | 60 | |
25 | 32.7 | ||||||||||||
38 | 3.5 | 14 | 55 | ||||||||||
50 | 0.8 | 3.1 | 13 | 29 | |||||||||
65 | 0.8 | 3.2 | 7.1 | 13 | 20 | ||||||||
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