Disc valve with spheroidal graphite cast iron dn80 wafer/flange version

When you hear about valves made of nodular cast iron, you immediately remember how many times you had to explain to customers the difference between wafer and flange designs. Especially with DN80 - the same diameter where many people mistakenly believe that they can save on seals. Last month, they were just redoing a unit at a pumping station, where they installed a wafer version without taking vibration into account - six months later it started leaking down the rod.

Features of material and execution

Nodular graphite in cast iron is not just marketing. In 2021, at the facility of Shandong Lingyao Intelligent Agriculture Technology LLC, three conventional cast iron valves had to be replaced with spheroidal graphite versions. The reason is constant water hammer in the drip irrigation system. After analysis on the website https://www.lyzhihuinongye.ru, we chose exactly this solution for smart agriculture projects.

The wafer design often seems easier to install, but if the flanges are not properly machined, misalignment is guaranteed. Once at a heating station it was necessary to dismantle the entire assembly due to a millimeter displacement. Although flanged is heavier, it provides more opportunities for adjustment, especially when the pipeline is assembled with a “reserve” in length.

DN80 is the same diameter where serious calculations for deflection are already needed. I remember that in 2019, valves were installed at a water filtration facility without additional supports - six months later a leak appeared in the places where the drive was attached. Now I always check the design diagram of the pipeline before choosing a design.

Installation practice and common mistakes

I constantly encounter one mistake with wafer valves - installers tighten the studs without a torque wrench. As a result, the saddle becomes warped and the disc begins to jam after the first year of operation. Particularly critical for variable frequency systems where positioning must be precise.

In agricultural automation projects such as those implemented by Shandong Linyao LLC, temperature expansions are often forgotten. Once I had to redo a unit in an intelligent greenhouse complex - in the summer at +35°C, the wafer valve jammed due to stress in the pipeline.

The flange version, although more expensive, makes it possible to install additional seals. At one of the facilities for remote control of valves, paronite gaskets with metal reinforcement were used - the result exceeded expectations, even with vibrations from pumping equipment.

Operational Observations

Over 12 years of work, I remember an incident at a filtration station, where DN80 wafer valves operated at 40-60% opening. Two years later, erosion appeared on the discs. It turned out that cavitation was due to incorrect selection of pumping equipment. Now I always advise customers to calculate operating modes.

In fertilizer systems, it is important to consider the chemical composition. Once we installed standard valves in the ammonium nitrate supply line - six months later problems began with the rod seal. I had to switch to specialized models with EPDM protection.

For water treatment projects, it is important to consider the presence of abrasive particles. At one hydraulic construction site, three valves had to be replaced in one year due to seat wear. Then we switched to versions with reinforced rings - the problem was solved.

Compatibility with automation systems

When integrating with frequency converters, a problem with disk 'bounce' often arises. This is especially noticeable on diameters such as DN80, where the masses are already significant. Last year, we set up the system at the facility of Shandong Linyao LLC - we had to modify the control algorithm for smooth operation.

Electric actuators for flange versions require more powerful brackets. I remember how at one of the agricultural facilities they saved money on fastening - after a month the drive came off along with part of the flange. Now I always check the calculation for torque.

For remote control, it is important to consider signal delays. In smart irrigation systems, I sometimes observed desynchronization when using wireless modules. We decided to install local controllers directly at each gate.

Maintainability and maintenance

Wafer valves are more difficult to repair - often you have to disassemble a section of the pipeline. At one service facility, an entire section had to be cut out to replace a seal. With flanged ones it is easier - they can be dismantled separately without affecting adjacent equipment.

Replacing the stuffing box seal is a common procedure. I noticed that on DN80 it is better to use stacked stuffing box packings rather than standard rings. Especially in systems with pressure differences, there is less likelihood of leaks along the rod.

During routine maintenance I always check the condition of the saddle. Somehow I missed a microcrack on the wafer valve - six months later, during hydrotesting, we got a rupture in the body. Now I use the endoscope for internal examination without dismantling.

Economic aspects of choice

The cost of installing a DN80 wafer valve may be lower, but if you take into account possible repairs in the future, it is not always profitable. On large projects like those being built by Shandong Lingyao LLC, the total cost of ownership is considered, not just the initial investment.

For long-life projects, such as smart agricultural parks, it is important to consider the availability of spare parts. Flange versions usually have a better repair base, especially for drives from European manufacturers.

When integrating into existing systems, there is often a need for adaptation. I remember a case when I had to redo the fasteners to install a flanged valve instead of a gate valve - the additional work amounted to almost 30% of the cost of the equipment.