Ball valves

When they talk aboutball valves, many people immediately imagine simple shut-off valves - they say, what’s so complicated about it? But in practice, it turns out that the selection and operation of these units in drip irrigation systems has a lot of nuances that become visible only after several seasons of operation. For example, in the projects of Shandong Linyao Intelligent Agriculture Technology LLC, we initially used standard brass valves, but quickly encountered a problem - in water with a high salt content, they began to leak within six months.

Design features of ball valves

If we take it specifically for agricultural systems, then the main difference is the material of the seals. Teflon ones are good for clean water, but in the presence of small abrasive particles (sand, silt) they wear out quickly. In our projects we switched to EPDM seals, although they also have restrictions on the chemical composition of water.

I noticed an interesting detail: many manufacturers indicate operating pressures of up to 16 bar, but do not specify that when constantly operating at pressures above 8 bar, the service life of the rotating mechanism is sharply reduced. This is especially critical for systems with frequent starts/stops.

By the way, about the sizes - in catalogs they usually indicate DN15-DN50, but in practice for long irrigation lines it is better to take a size larger. This reduces hydraulic losses and compensates for possible overgrowing of the seats.

Installation and operational problems

The most common mistake installers make is installationball valveswithout taking into account the direction of flow. Although they are structurally symmetrical, if the orientation is incorrect, the force on the handle increases. They tested it at a facility in the Krasnodar Territory - the difference in turning force reached 40%.

Winter preservation is a separate topic. If you do not drain the water completely, freezing destroys not only the body, but also deforms the ball. Moreover, visually this may not be noticeable until the first launch. There were cases when the valves looked normal after wintering, but let water through in the “closed” position.

Another point is the connection of electric drives. Many people think that they can install any compatible drive, but gaps in the connections lead to backlash and inaccurate positioning. We in Shandong Lingyao have developed the technology for selecting and installing drives, now the operating error does not exceed 2-3 degrees.

Compatibility with automation systems

For remote control, it is important to consider not only the moment of operation, but also the speed of rotation. Rapid opening/closing causes water hammer, especially in long pipelines. We had to develop stepwise control algorithms - first we open it slightly by 25%, then smoothly until it opens completely.

Integration with SCADA systems requires the installation of position sensors. Non-contact Hall sensors have shown optimal reliability indicators, but their cost is higher than limit switches. In budget solutions we use a combined scheme.

An interesting incident occurred at a facility in the Rostov region - during the simultaneous opening of a groupball valvesthe pressure in the line dropped. It turned out that the problem was the insufficient diameter of the supply pipeline. I had to recalculate the hydraulics of the entire system.

Maintenance and repair

Maintenance regulations are often underestimated. At least once a season you need to check the ease of movement of the handle - if the force exceeds 5-7 Nm, then there are already problems with the seals or bearings.

Replacing the O-rings seems like a simple operation, but there is a caveat: you cannot use silicone lubricants, they destroy EPDM. Only special compounds based on Teflon. We found this out after seals at one of the facilities failed en masse after the first maintenance.

Calibration of electric drives is another important point. It is impossible to make precise adjustments without special equipment. We use portable testers that allow you to set rotation angles with an accuracy of 0.5 degrees.

Promising developments and modernizations

Now we are experimenting with anti-vandal design - installing protective covers on handles and electric drives. In field conditions, this turned out to be in demand - the number of unauthorized interventions decreased.

We are testing models with a double seal - an additional Teflon ring on the stem side. So far, the results are encouraging: the service life has increased by approximately 30% compared to standard versions.

For particularly critical areas, we are considering the option of leakage sensors - they are installed directly on the housingball valveand respond to drip seepage. However, the cost of such a solution is still high for mass use.

Integration into complex systems

In the projects of Shandong Linyao Intelligent Agriculture Technology LLCball valvesrarely operate in isolation - usually part of a distributed irrigation control network. Therefore, compatibility with various communication protocols is important. Modbus RTU and Profibus proved to be the most stable.

When designing large systems, we take redundancy into account - critical lines are equipped with paired valves with automatic switching. This increases the reliability of the system as a whole, although it increases the cost of the project.

The latest development is integration with weather stations. The valves automatically adjust the operating mode based on the precipitation forecast. Water savings reach 15-20% compared to traditional timer control.