Metrological technical characteristics of large diameter mechanical water meters

Abstract: The current water meter market is increasingly competitive, and the shape and characteristics of the products are getting closer, so the quality of the products has become a key point of competition. Large-diameter water meters are generally used in the main pipe of water pipelines, which plays a role in measuring the total water volume. The importance is self-evident. Once the quality problems of large-diameter water meters appear, it is not only troublesome to change tables, but more importantly, users who affect water use. And it is not a problem that can be solved in a moment. If you want to make a water meter, you must understand its technical characteristics. Only in this way can you really make a good water meter.

 

Keywords: water meter, screw wing, characteristics

 

The large-diameter mechanical water meters currently on the market are mainly divided into a rotary wing type and a screw-wing type from the mechanical principle, and their main difference lies in the shape of the impeller. The rotor-type impeller blades are the same as the small-diameter impeller blades, and belong to the evenly distributed plate-like blades, while the screw-wing blades belong to the same uniformly distributed spiral blades, which give them water in the water meter. The forces are very different. Let's analyze their respective metering characteristics.

 

1. Rotor-type large diameter mechanical water meter

At present, the rotary-wing large-diameter mechanical water meter on the market is mainly horizontal-rotor type. The metering principle is that water enters the water meter from the water inlet, and then the impeller is rotated by the filtered water net and the impeller box. Finally, the gear of the counter is driven by the gear above the impeller. Count it. The whole process affects the flow of this water meter mainly by the impeller box, and the impeller box has three aspects that affect the flow.

 

（1）Flow hole

The main function of the flow orifice is to regulate the flow. It can play a fine-tuning effect on the flow of the water meter and is an important place to calibrate the flow. Another characteristic of the flow hole is the inclination of the hole. The magnitude of the inclination can directly control the impact force of the water on the impeller, thereby affecting the rotational speed of the impeller.

 

（2）Impeller steering hole

The impeller steering holes are generally distributed around the impeller box. There are two main functions. The first is to control the direction of rotation of the impeller, and the other is to control the flow of water. This controlled water flow is the accuracy of controlling the approximate overall flow of water. The accuracy is adjusted by the flow orifice, so this is a very important place. Once the deviation is too large, the flow orifice cannot calibrate the flow.

 

（3）the tip of the impeller box

The role of the tip of the impeller box is to adjust the upper and lower gaps of the impeller and the height of the impeller and the impeller box. Although these two effects also have an effect on the flow, its main function is not to control the total amount of flow, but to control the influence of the flow rate on the flow in certain intervals, which plays an important role in regulating performance.

 

2、screw-wing large diameter mechanical water meter

The screw-wing large-diameter mechanical water meter is generally divided into a horizontal screw wing type and a vertical screw wing type from the structural principle. The horizontal screw-wing metering principle is that water directly impacts the impeller through the rectifier, the impeller rotates through the worm drive to drive the helical gear shaft, and finally the central gear on the helical gear shaft drives the transmission gear on the counter to count, while the vertical screw-wing metering The principle is basically similar to that of the rotor type, except that the shape of the impeller is different. The impeller blades of the screw-wing water meter are spiral, and the main performance of the screw-type water meter is the rectifier, the impeller and the regulating piece, and their functions are also different.

 

（1）Rectifier

It is not difficult to see the effect of the rectifier from the literal side, that is to play the role of rectification. Before the water enters the water meter, the first step is to pass the rectifier. Only after the rectifier hits the impeller, the water will strike evenly. The force on the impeller will be basically uniform, and the friction of the impeller will not be biased to one side, which will not cause wear. Parts are not wear resistant.

 

（2）Impeller

The most important part of the performance of the screw-type water meter is the impeller. Its blades are spiral, and the difference between the rotation angle and the rotational distance of the blades has a great influence on the performance. Only after many trials can we find the best point, so the performance of the screw-type water meter should be It is better to say that it is necessary to make its impeller blades.

 

（3）Adjustment sheet

The role of the regulating piece is the same as that of the flow-type hole of the rotor-type meter. It also acts to fine-tune the flow rate and is used to correct the total flow of the water meter.

The above is the part of the rotor-type mechanical water meter and the screw-wing mechanical water meter that affect the flow, but there is an important part to really make a large-diameter mechanical water meter, that is, wear-resistant parts. Because the large-diameter water meter has a fast flow rate, a large flow rate and a strong impact force, the quality of the wear-resistant parts determines the correct metering life and even the service life of the watch to a certain extent.

In fact, large-diameter mechanical water meters in addition to the above important parts, there are many small places to pay attention to, such as the cooperation between parts, the gears between the gears, etc., all need to be carefully designed and calculated. We only need to consider all the places and do our best, and good products will naturally be born!

 

References:

[1]GB/T 778.1-XXXX 《饮用冷水水表和热水水表第一部分：计量要求和技术要求》

[2][1] GB/T 778.1-XXXX "Drinking cold water meters and hot water meters - Part 1: Quantitative requirements and technical requirements"