Electric disc valve

When it comes to electric disc valves, many people immediately imagine the simplest locking mechanisms, but in reality these are complex control devices where every millimeter of the disc stroke affects the flow rate. In our work with Shandong Linyao Intelligent Agriculture Technology LLC, we encountered the fact that some suppliers simplify the design by removing precision encoders, which leads to pressure floating in the lines.

Design features of disc valves

Unlike ball valves, where there is only an 'open-closed'electric disc valveallows you to smoothly regulate the flow by rotating the disk to a precisely specified angle. But there is a nuance: if there is sand suspension in the system, standard Teflon seals are worn out over the course of a season. You have to order ceramic coatings - it’s more expensive, but for projects like smart greenhouses it pays off.

I noticed that catalogs often do not indicate the actual service life at different pH environments. We once delivered a batch of valves to a facility with a high salt content - after three months, play appeared in the drive. We had to urgently change to models with an aluminum-bronze alloy, although the project initially provided for standard options.

Now for most of our projects, for example in the construction of hydraulic structures, we use valves with a double seal - the main one is silicone, the backup one is EPDM. This increases the cost by 15-20%, but reduces the risk of leaks in automated irrigation systems.

Integration into automation systems

When connecting to controllers, there is often a problem with zero point calibration. Especially in systems where frequency automatic equipment is used, the slightest shift in the settings leads to the fact that the valve either does not close enough or creates excess pressure. We have developed our own calibration technique using high-resolution pressure gauges.

An interesting case occurred at a facility in the Krasnodar region: when 12 valves operated simultaneously in one line, water hammers occurred. It turned out that the problem was different response times of the drives - even a discrepancy of 0.3 seconds caused pressure surges. We decided to install buffer tanks and synchronize through the main controller.

We are currently testing a new system for remote control of valves with feedback based on current consumption - this allows us to monitor the wear of the electric drive brushes and predict maintenance. There are plans to implement this at all facilities of Shandong Linyao LLC.

Practical aspects of installation

When installing in the field, the need for precise alignment is often overlooked. If the actuator axis is offset relative to the valve seat by only 1-2 degrees, this leads to uneven wear of the disc. We use laser centerers, although many contractors still work 'by eye'.

Another important point is the orientation of the valve in space. For vertical installation, additional support brackets are needed, otherwise the shaft will sag over time. In one smart agricultural park project, 30 valve mounts had to be redesigned due to this error.

Thermal expansion is a separate issue. When installing in regions with daily temperature changes of more than 15°C, it is necessary to leave thermal gaps. Once in the Astrakhan region the valves “stuck” after the first cold night - compensators had to be added.

Operational problems and solutions

The main problem is calcium deposits on the disc. Standard chemical flushing is not always effective, especially if the water has a high iron content. We have developed a combined method: first acid washing, then ultrasonic cleaning without disassembling the unit.

Electric drives are sensitive to voltage changes. In field conditions, stabilizers often fail, so we now install additional protection units with varistor protection. This increases system reliability by 30-40% according to our observations.

It is interesting that most failures do not occur at peak moments of operation, but during transient modes - start/stop. Therefore, we are now paying special attention to setting up smooth acceleration and braking of drives.

Prospects for technology development

Now I see a trend towards the intellectualization of simple mechanisms. New modelselectric disc valveare equipped with torque and temperature sensors, which allows predictive maintenance. At Shandong Lingyao Co., Ltd. we are testing a system where the valves themselves indicate the need to replace the seals.

At an exhibition in Moscow I saw interesting developments with magnetic couplings instead of mechanical gears - there are no wearing parts, but the price is still high. I think that in 2-3 years such solutions will become more accessible.

For high quality agricultural field projects we are currently experimenting with valves with a digital communication protocol instead of analogue 4-20mA signals. This reduces the positioning error to 0.1% versus the standard 1-2%.

Overall,electric disc valveturns from a simple locking device into an intelligent system unit. And this is logical - after all, the accuracy of irrigation directly affects the yield. In our projects we are already seeing a 15-20% difference in water efficiency when switching to smart closed-loop valves.