Vibration isolation for pumping systems

~ The importance of quality engineering for effective pump isolation ~

Low-price acoustic products may have their appeal, however if they are not correctly engineered the consequences of failure could be devastating. In hazardous industries where safety is of the utmost importance, getting the vibration isolation right from the outset is paramount. Here Steve Hart, director at industrial vibration control specialist Mason UK, discusses the key considerations for effective pump isolation. 

The global industrial pumps market was valued at USD 60.21 billion in 2020 and is expected to grow at a compound annual growth rate (CAGR) of 3.9 per cent through to 2028. Pumps are used in water supply processes to move fluids throughout the pipe runs within a building, or series of buildings.  

The impeller within the pump creates regular pulses that can be transmitted through the water column within the pipework. The frequency of the pulses is determined by the pump speed and the design of the mechanism. These pulsations can sometimes coincide with the natural frequency of sections of pipework. Should this occur, it causes the pipework at that location to resonate and introduces noise and vibration into the building structure which in turn can cause disturbances throughout the building. In high precision Blue Chip companies for instance, these disturbances can affect production output by increasing failure rates in the production of expensive microchips.

If pumps aren’t isolated properly, resonances in the pipework can also lead to the fatigue of joints within pipe runs, increasing the risk of failure and the release of fluids into the building environment. If a serious leak occurs, it’s possible that the whole plant room may need to shut down, leading to costly maintenance works or major safety concerns. From damage to equipment to severe injury — the repercussions could be huge. 

To ensure that vibration caused by pumping applications is unable to pass into the main building structure, the disturbing forces should be isolated at source using suitable vibration control products. At Mason UK we’re often called upon to provide retrofit support for vibration isolation projects that have gone wrong. But how do you ensure the vibration isolation is right in critical pump applications the first-time round? 

Don’t compromise on quality  

The key to effectively isolating pump equipment is to isolate the vibration producing equipment at source from the main building structure. This would normally involve a combination of inertia bases, flexible pipe connectors and acoustic hangers. 

The first step involves isolating the pump from the building structure. The usual procedure for reducing structure borne noise and vibration levels is for the pump to be installed on concrete inertia bases mounted on high deflection spring mounts. The inertia base provides an air gap between the equipment and the structure, and the springs are normally selected to provide at least 95 per cent isolation efficiency from the main disturbing frequency of the pump.

The second step is to provide flexible pipe connectors or expansion joints at the inlet and outlet joints of the pumps. The main misconception is that these connectors accommodate differential movement and misalignments between pumps and the adjacent pipe work. While this is true to some extent, the main benefit of flexible pipe connectors is to interrupt the vibration pulses within the fluid created by the pump. When the pulses hit the arched construction of the connector the regular frequency of these pulses is changed into random patterns. With random frequencies passing through the fluid, there is no opportunity for coinciding resonances between fluid and pipework.

For piping systems, we recommend opting for flexible pipe connectors and acoustic hangers. To suspend the piping, you will need to use durable hangers. The selection of which will depend on load, frequency and other system specifications.  

Some applications require the flexible pipe connectors to be able to accept hot water, steam or chemicals passing through them at high pressure and elevated temperatures. Cheaper variations of flexible pipe connectors are generally moulded using EPDM with nylon reinforcement, and can become brittle if heated water passes through, leading to premature failure. 

In contrast, Mason Industries’ flexible pipe connectors offer superb durability and can be tailored to suit each project. The Mason Safeflex range offers unparalleled protection against failure. Every connector is pressure tested in the factory to 150 per cent of rated pressure prior to release. The special design features include a uniquely robust flange design with Kevlar reinforcement, which has fantastic heat resistance, wrapped around a solid steel ring preventing pull out failures.

Pump isolation often requires an engineered solution. We cannot stress enough the importance of getting vibration isolation right the first time around. The first step to effective pump isolation is partnering with experienced acoustic engineers. These industry specialists will be able to specify quality vibration isolation products that can be tailored to your project and will last the test of time. 

Are you looking for vibration isolation support for your pump application? Get in contact with Mason UK today to discuss your project’s requirements.