System Redesign Optimizes Hydraulic Elevators for Heavy-Duty Drum Dumping

In industrial processing environments, handling and dosing large volumes of liquid or semi-solid chemicals into high-capacity blenders is a critical operation. For a global food and beverage manufacturer, this task became a significant engineering challenge.

Their fruit preserve processing system used a hydraulic elevator system designed to lift and pour the contents of two 55-gallon drums of preservative into a 40-foot-high blender. Reliant on linear hydraulic cylinders, the existing design experienced recurring mechanical failures and operational instability, posing safety risks and costly, unplanned downtime.

An engineering team from Motion Repair & Services identified this as an opportunity for the manufacturer to optimize its operations. They successfully addressed these issues by creating a custom hydraulic system that resulted in improved throughput and cost savings.

This case study explores the challenges encountered in the initial hydraulic elevator design and analyzes how success was achieved through innovative mechanical redesign and hydraulic circuit improvements.

Hydraulic Elevator Experiences Persistent Maintenance and Performance Issues

The original hydraulic elevator was tasked with lifting two standard 55-gallon drums filled with preservative up 40 ft. and tipping the contents into a blender situated at this height. To accomplish this, the system employed a pair of linear hydraulic cylinders to control the tipping action, rotating the drum carriage approximately 120 degrees into the blender.

Frequent mechanical failures occurred primarily due to the force vector dynamics of the linear actuators relative to the tipping action. The linear cylinders generated force along an axis misaligned with the rotational tipping motion required. This misalignment caused only a small component of the cylinder’s force to contribute effectively to tipping. The larger component of the actuator-generated force imposed significant loads on the bearing and torque tube assembly, which were not optimized to withstand these stresses. This led to premature mechanical wear and failure.

The net effect was inefficient force transmission, excessive stress on structural components, and frequent breakdowns that disrupted production.

Beyond mechanical failure, the hydraulic control system exhibited critical circuit problems, including uncontrolled hydraulic flow. Control-valve failures allowed hydraulic fluid to flow unrestricted, causing the elevator carriage to move abruptly or “catapult” during operation. This sudden, uncontrolled motion posed safety hazards and risked damage to the drums and equipment.

The other main issue was a lack of flow regulation and motion control. The original circuit was missing the components required to modulate the flow, speed and acceleration of the actuators. These are essential features for controlled and safe dumping operations, especially when handling varying product viscosities from liquids to solids.

Hydraulic System Redesign Addresses Performance Challenges

To address the challenges Motion’s customer was experiencing with its hydraulic elevator, the Motion engineering team initiated a comprehensive redesign focused on optimizing the elevator system’s mechanical actuation and hydraulic control.

Switching From Linear Hydraulic Cylinders to Rotary Actuators

The key advancement creating the “magic” was in the creation of a new circuit design. This involved replacing the elevator’s pair of linear hydraulic cylinders with rotary actuators specifically selected and configured to improve tipping force and motion.

Some advantages realized with the rotary actuators included:

• Direct Rotational Force Delivery – Rotary actuators provide torque directly around the rotation axis needed for tipping the drums. This alleviated the force vector inefficiencies seen in the prior system.
• Reduced Bearing Load – By delivering torque without relying on off-axis force components, the stress on bearings and torque tubes markedly decreased.
• Compact and Durable Design – Rotary actuators often have more compact footprints and fewer linkage parts than linear cylinders using complicated lever arms, reducing mechanical complexity and potential failure points.

The new carriage design integrated the rotary actuators precisely aligned with the rotational bearing assembly. This arrangement ensured three key things — smooth, controlled tipping motions with optimally applied torque; improved mechanical robustness through balanced loading; and simplification of mechanical linkages, reducing maintenance demands.