Efficient sealing systems in fluid power applications

26 September, 2017

Even the smallest of leaks in hydraulic and pneumatic systems can cause appalling damage, so adequate protection against this potential problem is a top priority for fluid technology manufacturers. Here, high-performance adhesives and sealants are the key to success, offering a huge boost to efficiency and cost structure in the production of hydraulic and pneumatic components such as pumps, compressors, cylinders and valves.

Be it for thread-locking, thread-sealing, structural adhesion, retaining, cleaning or metal pre-treatment applications, fluid technology OEMs are able to access a broad plethora of solutions.

For instance, 100% leakage safety can be provided through high-performance anaerobic thread-locking, thread-sealing, retaining and gasketing. Similarly, lower cost is evidenced simply by comparing inexpensive liquid thread-lockers with mechanical fasteners, and liquid gaskets with O-rings. Another clear market need is for lighter and therefore more energy-efficient systems, where the use of structural adhesives can replace welds and deliver lightweight designs.

The benefits of such products in hydraulic and pneumatic applications are wide-ranging, and include not just locking and sealing functions, but compensation for relative movement and impact loads, corrosion protection, increased load transfer, structural integrity and uniform stress distribution.

Bonding and sealing also offers lower inventory versus mechanical fasteners and enhanced design freedom, while the potential for fully automatic dispensing makes for cost effective and fast production.

To provide an application example, consider a hydraulic pump. Here, can be found a number of thread-locking tasks on the centring and flange bolts (into the housing), as well as the use of retaining compounds for keyway to shaft and inner bearing ring to shaft applications. Fluid power OEMs can also benefit from the use of liquid gasketing on the rear flange to housing joint, bonding the radial shaft seal into the housing and thread-sealing of the outlet/inlet connections and plugs.

More potential applications

A hydraulic cylinder has perhaps even more potential applications for thread-sealing (oil inlet/outlet connections, barrel to cap end), retaining (oil impregnated bronze bushes), thread-locking (ball head to rod end, piston to piston rod, cap end head, rod end head), bonding (identification plate) and gasketing (cap end head, rod end head). There also exists the potential to take advantage of metal pre-treatment solutions for the rod end head, cap end head and rear spherical housing.

Further application examples include valve blocks, lock valves, flow control valves, directional valves, pneumatic screw compressors, hose connectors, sensors, oil filters, air dryers, water/oil drains, pressure vessels and pipes, to list but a few.

Among Henkel’s advanced product solutions are retaining compounds, which find favour in fluid technology applications for a number of reasons. For instance, they offer high load transfer and prevent fretting, corrosion and micro-movement. They are also vibration and impact resistant, and give the designer the opportunity to eliminate mechanical fasteners (thus saving costs), and use slip fits rather than interference fits.