February Meeting 2020

My Life in Oil - David Field

David began by saying that he had been in engineering all his working life.    Leaving Kingston Technical School with the appropriate qualifications he gained an apprenticeship at Vickers Armstrong’s (Aircraft Ltd) Weybridge factory working significantly in two departments.      The first being the Aircraft Laboratories where he tested to destruction various component test pieces and the secondly the Flight Test at Wisley, a small satellite airfield near-by.    Here he worked with engineers who tested systems in flight with what would now be considered to be Stone Age equipment taking down the readings from gauges to produce graphs.        The gauges were arranged in banks on racks and a camera would take shots at short intervals – these were very important for the safety of the aircraft.      On another occasion at Upper Heyford USAF Airfield he worked on the prototype P 1127 Harrier Jump Jet testing the newly invented Maxarat Anti-Skid device.   

On finishing his apprenticeship he worked in the Instrumentation Drawing Office as a section leader, producing all manner of instrumentation drawings connected with test flights including the attachment points for a water spray device on the tail plane of the VC 10.    Later, working in the systems Test Department and now classed as a Development Engineer his main task, along with others, was to develop the Hydraulic System for the Cargo Doors open and close mechanism on the VC10.     Later he also helped to develop, on a mock- up of the VC 10, Mechanical and Hydraulic systems which operated the landing gear, flaps, slats and ailerons etc.

When the aircraft industry was reorganised David joined Fairey Engineering Ltd in 1964 and was employed in the Development Department where the main focus was on Filtration of Hydraulic Oil used in Aircraft and Industrial Systems.       There was also some work being done, with the nuclear industry, on a Sintered Bronze Element to filter cooling water from the reactors.      The team tested all manner of filters including those of their competitors for their contamination capacity, their efficiency at removing contaminants and also pressure tested them to failure.

Every hydraulic system in whatever industry depends on filters to remove unwanted particles so as to prevent erosion of working components such as pumps, valves and cylinders.    These filters can be in one of four locations, suction filter to protect the pump, high pressure filters to protect the system components, return line filters to trap all the generated particles from the system and case drain filters to enable pump wear to be checked.          The main focus, as a company producing high pressure filters, was on filters to protect the valves, cylinders and motors which were crucial to the safe and long life of the system.        In order to determine the cleanliness of the system it was necessary to take samples and analyse the number of particles in it.      The team therefore developed a clean room and a dark room containing a back projection microscope.     The clean room was for cleaning all equipment necessary for the removal, containment and extraction of the particles.

      It is worth, at this point, defining the size of these particles.    Aerospace systems demand cleanliness down to 5 microns and industrial systems down to 25 microns.    A micron is one thousandth of a millimetre and is difficult to see without a microscope.        It was necessary to clean the glass slides on which the membranes caught the particles and it was necessary to clean the bottles in which the sample was taken.    It was also necessary to filter the cleaning fluid, Isopropyl Alcohol and check that.    All the cleaning fluids used were passed through a membrane and the particles counted on the back projection microscope.     Typically the aim would be for no more than 100 particles larger than the standard for that type of filter.    When the sample had been taken it was diluted with Isopropyl Alcohol in equal measures and drawn through a very fine membrane under vacuum to trap all the contaminates. 

     David sat on the industrial committee which set the standards for cleanliness and it was even found that the plastic coated card insert in the cap of the sample bottles to be a problem and these were replaced by a plastic film which was shown to be very effective.          Even the way on which a sample was obtained from a system had its difficulties as the act of loosening a coupling generated unwanted particles.          To this end a sampling valve was developed which allowed them to be taken from a live system without causing significant particles to be generated.          This contained a labyrinth which slowed down the flow and reduced the pressure.      However, the valve had to be flushed before taking the sample.          Eventually an electronic system for counting particles was developed in America which proved useful and simplified the system. 

HIAC  was a device which passed the sample through an orifice across which a light beam was passed.        The device measured the light interruption and after calibration was able to count the particles.        There was a degree of scepticism about this process and the industrial committee decided to make comparison tests.         David volunteered to carry these out and exhaustive tests showed there to be a good degree of comparison between the microscopic results and those of the electronic device.       As a result of this he became an ambassador for the machine and was asked to join the company.       His job was to demonstrate, sell and where successful install the device.

       Unfortunately the owners of the company decided to move and centre  the European operation in Brussels and David, using his contacts in the industry, was soon able to find another good position with Danfloss, a Danish Company.        The Company had international connections and manufactured and sold all sorts of control equipment which included oil burning heating controls, central heating controls, condensers for refrigeration and hydraulic motors and steering valves and pumps.           He was employed by the hydraulic division and was responsible for sales in the South of England.

        He was with the company for 25 years and later moved into the office to become Internal Sales Manager and then into a position to support the Major Customers.    Here he was responsible for the development of a Sales Forecast System which enabled the area Sales Managers to input their sales forecasts on line.          In doing this he recorded the sales results and prepared sales graphs etc for meetings both in the UK and Denmark.        When the company merged with another hydraulic company and moved to another location he received a good redundancy package and has found many interest to keep him occupied in retirement.

Questions were put to him by Colin Kyte and john Demont and Acting President David Richardson thanked David for a very interesting and detailed talk which had been very much enjoyed by the Club.

                                                                              Report by David Field


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