Rotary valves need to be in premium condition to keep the system operating safely and smoothly. Should you encounter a problem with your rotary airlock feeder, the system must be halted to perform repairs, taking significant time and expense. However, with proper and regular rotary valve maintenance, you can avoid these costly repairs and downtime. This not only results in smoother conveying operations, but also better valve performance.

What Is A Rotary Valve?

Rotary valves (also known as rotary airlocks, rotary feeders, etc.) are pneumatic valves that handle and meter the flow of granular bulk or powders. Material is fed into the valve via a hopper or other inlets, handled through the valve rotor, and then deposited onto a conveyor system in discrete packets, all with minimal pressure loss. They are most often used in air conveyer systems to minimize the loss of pressure across the valve, but rotary valves are also used to meter materials at a controlled feed rate. They work almost exclusively in air systems and function as airlocks, explosion/flame barriers, and process isolators, among others. They can move dry to slightly sticky products, and find many applications in chemical, food, pharmaceutical, plastic, and other manufacturing markets. Below are easy to follow maintenance steps to help you care for your rotary valves and prevent costly downtime.

Visually Inspecting The Valve Interior

Check blade-to-housing and blade-to-head plate clearances and the condition of the rotor, rotor blades, flexible seal strips, housing, and head plates. You can inspect the valve either through an access door (if the valve is so equipped) or by partially dismantling the valve.

Checking The Shaft Seals For Tightness

Check the condition of the rotor shaft support bearings for excessive play and smooth operation. Replace them regularly before they are severely worn as this can affect rotor position in the housing and lead to damage from metal-to-metal contact. Check at least monthly.

Checking The Speed Reducer Oil Level

Improper lubrication is among the leading causes of gearbox failure. Thus, it makes sense that proper lubrication plays a key role in achieving satisfactory performance and extending the life of gear (or speed) reducers.

Adjusting The Drive Chain And Sprockets While Ensuring The Guard On The Drive Chain Is In Place

When inspecting the rotary valve, adjust the drive chain and sprockets to make sure the sprockets are aligned, and the chain is correctly tensioned. This ensures the guard on the drive chain is in place before completing the maintenance.

Why Purchase A Rotary Valve Rotor Contact Detection System?

Rotary valve rotor contact detection systems have been getting more popular in recent years. Many of the leading sanitary rotary valve manufactures now offer a system that monitors electrical isolation of the valve’s rotor to the housing, alarming when rotor to housing contact occurs. This device continuously monitors the electrical isolation between the rotor and valve housing, giving an immediate warning of any rotor contact, or presence of a metal shaving lodging between rotor and body. Theses system are a great investment for preventing expensive damage to your rotary valves and feeders.

Make Sure Your Staff Is Trained In The Specific Rotary Valves At Your Plant

As simple as rotary valves may seem, each manufacturer’s design is different and requires in depth knowledge of proper maintenance and repair.  Make sure you train your operators and maintenance technicians on your particular rotary valve.  Make sure everyone who touches the rotary valves knows what they are doing.  Conduct routine training with a qualified representative or technician to show how to properly clean the valves, how to properly disassemble the valve and how to prevent damage to the sensitive rotor tips and housing surfaces.

How often you should perform each step depends on how many hours or shifts your system operates per week and the maintenance schedule for the rest of your conveying system and other plant equipment. Work with your valve manufacturer and maintenance workers to establish a schedule that’s practical for you. Also plan to document the procedures so you have a record of when maintenance steps have been performed.