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The Anatomy Of A Centralized Lubrication System: Series Progressive (Or Single Line Progressive) Systems
"Arguably the best engineered of all lubrication systems, the Series Progressive (or Single Line Progressive) system pumps oil or grease in either a cyclical (total loss) or continuous (recirculative) manner. Engineered to positively deliver an exact displaced amount of lubricant to every single bearing point, the divider block design is capable of operating in severe environments and accommodating upwards of 200 delivery points in a single pump system.
Today, most lubrication OEMs offer a version of this popular system type. The original model—designed and developed in the U.S. by the Lubriquip organization in the early part of the 20th century and marketed under the Trabon name—continues to be sold today.
How This System Works
A lubricant pump is connected to an engineered network of series progressive divider blocks, and via a controller is allowed to pump lubricant in a continuous or controlled cyclical systematic manner to each divider block.
Divider blocks, which are built in a modular style, contain a series of lapped, hydraulically actuated spool valves sized for varying displacements. The ability to "cross-port" a valve results in "doubling" the delivery of lubricant on one side of the valve only. The valves are progressively linked together in series, causing them to "shuttle" over to one side of the block in a progressive pattern, then to "shuttle" back to their original positions as the lubricant continues to be pumped through the block. Because of its hydraulic nature, as a valve is shuttled back and forth, it displaces a lubricant charge on one end of the valve to the bearing point, while simultaneously filling the void on the other side of the valve in preparation for displacement once the valve "shuttles" back.
Monitoring The System
To ensure every point has delivered a charge of lubricant, the first valve in the divider block can be attached to a cycle pin indicator that visually indicates the block has completed one full cycle by moving in and out one time. Attaching a counter/timer control to the cycle pin will indicate if no delivery has taken place within a given time period and signify a broken main delivery line.
Blocked and crimped lines can be visually detected via simple mechanical overpressure indicators connected at the secondary delivery-line block outlet. Whenever a "restriction"-caused hydraulic backpressure is sensed, a visual indicator pin "pops" up to indicate the exact line/bearing point requiring maintenance. If no electronic alarm sensors are used, operations and/or maintenance must perform regular visual checks for alarm indications."
-Excerpt taken from the book "Lubrication for Industry"
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