Machinery installation best practices

Follow these steps to avoid downtime, poor product quality, reduced capacity and high operating costs.

By Keith Mobley, contributing editor

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Proper machine installation is critical in maximizing reliability and minimizing life cycle costs. Conversely, improper installation is a chronic source of downtime, poor product quality, reduced capacity and high operating costs. While installation requirements vary depending on the type of machine and its function, there are basic best practices that must be followed.

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Foundation

Determine whether the support structure (foundation) has sufficient mass and stiffness to permit the machine to operate in or near a state of equilibrium. Lack of mass and/or stiffness causes normal operating forces to generate abnormal vibration levels that reduce useful life and increase the frequency of maintenance.

The foundation must be capable of carrying the applied load without settlement, flexing or crushing. Foundations for heavy machinery are usually concrete or structural steel structures. For these installations, an independent concrete pad is poured that has sufficient mass and stiffness to support the machine-train and absorb the forces generated by normal operations. The total foundation mass and its related support structures should be at least five times the total rotating or moving mass of the machine-train.

Some machines must be mounted on a mezzanine. In general, these machines do not have an adequate support structure. Also, direct mounting on concrete or deck plate floors introduces a resonance problem. Normal operating forces are transmitted directly into the floor, which acts as a soundboard and amplifies these energies. In the best case, these amplified energies only result in higher than normal noise levels. In many cases, they coincide with one or more natural frequencies of the machine or foundation and can result in serious, chronic problems.

Anchoring

Anchor bolts secure the machine to its foundation. The use of proper methods ensures a rigid, permanent mating of parts. When machines are anchored to a concrete foundation, J-bolts are fixed into the concrete as it is poured. Size bolts to ensure adequate holding torque and to prevent them from loosening over time. Exercise care when selecting the grade of bolt, and determine if the mounting pattern will be rigid enough to lock mounting plates to the foundation. The use of hydraulic concrete and straight mounting bolts is not recommended because these bolts tend to loosen with time.

For machines mounted on mezzanines or upper floors, anchor bolt selection and configuration is even more critical. In this case, the anchor bolts must perform two critical functions: they must fix the machine in place so it cannot flex, bend or deflect; and they must isolate the machine from the foundation to prevent transmission of generated energies into the foundation.

Isolation

Proper machine installation is critical in maximizing reliability and minimizing life cycle costs.

– Keith Mobley, contributing editor

Machinery generates energy (vibration) that must be either absorbed by the foundation or trapped within the machine. Cross talk, in which energy generated by one machine is transmitted into another machine, is a chronic source of reliability problems. This is especially true in plants having multiple continuous process lines such as paper machines, high-speed printing and metal processing lines.

When a machine is mounted on a concrete pad, the pad should be independent from the surrounding floor. Normally, the pad is formed and poured directly on bedrock and has a ?-in. to 1-in. separation between it and the surrounding floor to ensure isolation. This allows energies generated by the machine to be absorbed and prevents outside sources of vibration from entering the machine.

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