Self-levelling Hydropneumatic Suspension of the Citroen DS
You may remember the a famous application of hydraulic seals in the hydropneumatic vehicle self-levelling suspension. This was a new technology element of the iconic Citroen DS car that was manufactured between 1955 and 1975. This ground-breaking technology was, believe it or not, a novel “hydraulic seal” application at it’s launch. Continue reading
There are many applications where pumping high temperature water and aggressive fluids such as petrol, jet fuel, solvents, bleaches and other caustic solutions, dyes, liquefied gases and acids are part of the process. In a lot of these applications, it is impracticable to lubricate the mating and sliding surfaces or to contain the hot fluid using normal hydraulic seals without leakage. Continue reading
Hydraulic seal failure on site
In previous articles, we have referred to hydraulic seal failures and used the example of a plant hire mechanic up to his ears in site mud and surrounded by dust whilst repairing an errant digger hydraulic ram. Continue reading
Wiper Seals
Modern hydraulic seals are just as much constructed to close tolerances as the remaining hydraulic components for efficiency and longevity in service. Continue reading
I don’t know about you, but I am fascinated by aviation in all its forms, commercial, military and general. The need for security of hydraulic seals in this industry is absolute whether it relates to a massive state-of-the-art Rolls Royce Trent engine main bearing seal, the humble fuel transfer pump, the moving aerodynamic surface hydraulic actuation systems or the landing gear actuating systems. Any failure of hydraulic seals in any of these systems has the potential for major calamity and loss of life. Continue reading
The Hydraulic Seal industry has come a long way since the age of steam with the development of rubber piston seals, wiper seals and rod seals to ensure that hydraulic systems can deliver effective work with the minimum flow-by and leakage from the system. Our Victorian engineer forebears soon realised that hydraulic systems are a really effective and elegant solution both as a force multiplier and a means of transferring water and other fluids from one place to another. Continue reading
Typical North Sea Turbine
Alternative energy is certainly here to stay and some say it won’t be too long before it won’t be alternative as fossil fuels and nuclear energy are phased out. One of the most visible manifestations of this new energy are the forests of wind turbines that “grace” our hilltops and estuaries. The turbine designers and hydraulic seal manufacturers are finding a whole set of new challengers which will, no doubt, spawn many new developments. Continue reading
Now you like me would probably think that gearboxes with oil contained within them would just need hydraulic seals at the inlet and outlet shafts and good ring seals on the lube pump circuit pipes for a good seal to be maintained to keep the oil in. If you think of a car gearbox, this is what you get. The hydraulic seals are designed to resist the relatively modest temperature-induced pressure of the oil/vapour/air mix within the gearbox. Continue reading
I came across an interesting statistic from an industry expert that stated that over 70% of spare parts and hydraulic seals sold for hydraulic machinery are used to replace defective components. He goes on to say that the cause of some 90% of these defects can be traced to improper operation or maintenance. This seems to be an alarming statistic until one realises that that a good chunk of hydraulic machinery is of the mobile variety working on construction sites or in other challenging environments where piston arms get bent or dirt gets into the hydraulics. Continue reading
In our last article, we touched on a the use of a relatively new specialised raw material for hydraulic seals, DuPont’s new Kalrez Spectrum perfloroelastomer which is used for extreme low temperature applications as found in the depth of freezers and on pipeline installations in the wilds of Siberia and Alaska. We felt that it is timely to both remind the cognoscenti of hydraulic seals and inform newbies to this very specialised subject, of the different types of raw material in use today. Continue reading
