Why McLanahan Horizontal Screens?
McLanahan’s MAX Horizontal Screen is a triple-shaft screen that can be used in a portable plant application or as a stand-alone product in fixed plants. It is typically used in finer screening applications that are horizontal. The McLanahan MAX Horizontal Screen provides you with a screen design that sizes and separates material more accurately and efficiently than an Inclined Screen.
The McLanahan MAX Horizontal Screen line continues on the strength of the MAX Inclined Screen. These high G-force, triple-shaft, oval stroke machines are known for their efficiency and reliability. With features like high-strength steel side sheets, strong fixture-welded screen decks, easy change springs, and quick knockouts for wet screen applications, the MAX Horizontal Screen is the next level in triple-shaft, oval-stroke screens.
Additionally, Horizontal Screens typically offer better efficiency (accurate particle sizing) than Inclined Screens because the material is retained on the screen longer, with a slower travel rate to the end of the screen. This allows more properly sized material to fall through the screen openings. In a stationary plant setup, they are more often seen as tertiary (third stage) and/or finishing screens. Horizontal Screens are also often specified for portable plants because of their low profile.
How Horizontal Screens Work
Horizontal Screens are utilized as a low height aggressive action screening device. They are built with a dual shaft (creating a straight line action at approximately 45 degrees to the horizontal) or a triple shaft (creating an oval action with adjustable stroke angle typically between 30 and 60 degrees from horizontal). A primary feature of the Horizontal Screen is its aggressive action in applications where blinding or plugging of the screen media openings can occur.
Horizontal Screens operate at zero degrees, but can be adjusted to about 10 degrees in either direction, allowing them to function at a lower overall height than inclined screens. They can have two or three shafts located within the screen box’s center of gravity, with timing gears and counterweights designed to provide either an oval or a linear motion, or they can provide linear motion via out-of-balance motors or geared exciters, within which eccentric weights are mounted onto both ends of a shaft located above the screen box’s center of gravity to provide vibratory motion. Horizontal Screens provide high G-forces to vibrate and move the material down the length of the screen.
Facts About Horizontal Screens
- Flat screens operate at zero degrees.
- Provide a lower profile height for increased suitability on portable plants.
- Generates more G-force required to dislodge particles that might potentially blind incline screens.
- Produces an oval stroke pattern that can be adjusted to suit the application for increased flexibility through manipulating stroke length and timing angle.
- Triple-shaft design distributes the load over a larger area and utilizes smaller bearings that can run faster and provide a longer operating life.
- Produces a consistent material travel speed along the entire length of the deck. The screen can also be configured to enable a slower travel speed than Inclined Screens for higher efficiency.
- The relationship of the trajectory to the screening media is at a true right angle, where Inclined Screens essentially reduce the amount of open area. Inclined Screen operators often compensate for this by installing cloth with slightly larger openings than the desired top size.
Benefits of McLanahan Horizontal Screens
- Easy stroke adjustment
- Grade 50 side plates are two times stronger than standard steel
- Rugged, computer-optimized decks with full-length bracing
- Simple to use and simple to maintain rubber snubbers
Frequently Asked Questions
How do I calculate screen efficiency?
Screen efficiency is the ratio of the material that passes through a screen opening to the amount of carryover that passed through.
What efficiency should I expect from my screen?
Do not always expect to get maximum screening efficiency on multiple deck screens because a multiple deck screen is always a compromise. If we set the stroke coarse for the upper deck, it may be too coarse for the lower decks. Also, on multiple deck screens, the lower deck will not see material down the entire area of the deck. By the time the material passes through the upper decks to reach the bottom deck, we may have lost as much as 20% of the lower deck.