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HH Roberts Machinery Ltd
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Hauerwas valve grinding machine logo
Hauerwas Valve Repair Machines

HH Roberts Machinery sold the first Hauerwas valve grinding and lapping machines to Ontario Hydro about 1970.
Hauerwas is the world leader in portable machines to repair valve seats on pipes in-situ.
display of Hauerwas valve reipair machines
The machines are available in 2 basic categories

  • mobile or portable units to be mounted on valves in position in the pipe system allowing repair without the need to remove the valve

  • stationairy models for repair and/or production of valves.

    • The technology of the planetary discs:

    The Hauerwas planetary disc is a carrier for different working tools mounted onto swivel holders These can be:
    • steel carrier discs for attaching self-adhesive grinding sheets- or discs
    • lapping discs made from cast iron, for working with lapping paste
    • high performance grinding discs coated with CBN or diamond, for high material removal
    • honing stones
    planetary disc sets for valve regrinding
    Expanded and contracted positions of a planetary disc
    cutting path of the planetary discs
    This illistrates the path traces for the tools on the discs. 
    Assembly of the planetary discs for valve re-grinding
    The planetary disc on the left has a steel disc set for adhesive backed a abbrasives

    On the right cast iron set of lapping discs are fitted for use with lapping compounds
    Click for a larger image
    Assembly of the planetary discs
    Click on the image for a larger view
    On the left is a view of the planetary disc from the drive side.  The seat of the ball mandrel can be seen.  One spindle has it's protective cap on, the others are removed to expose the bearings.  

    On hte right the individual adjustable arms can be seen. In this case they are fitted with high performance CBM grinding discs.
    Click for a larger image
    side view of the assembly of the planetary discs
    Assembly drawing of the planetary discs.

    Planetary Discs
    The base of the planet discs is made from steel or aluminium. On the circumference there are location holes for swivel arms in accordance with the diameter of the base. There are ball bearings in the swivel arms which serves to receive the desired machining discs. As a result of their individual rotary motion, these produce a surface appearance similar to cross grinding. The swivel arms can be swung out progressively. In this way, different diameter ranges can be machined with one planet disc.

    Pay attention to the following when adjusting:
    • The swivel arms must always be mounted so that, in the case of a collision in the valve casing, they do not unlock but can safely fold in the direction of rotation. This prevents possible damage to the machine and the casing which can arise due to inattention.
    • The swivel arms should, ideally, be adjusted so that the centre point of the machining disc lies slightly within the centre line of the valve seal surface. In this way, the machining discs are forcibly moved in a rotary motion and the bearing load remains small.

    Exchanging the machining discs:
    in accordance with the assembly instructions.
    For changing the working disc the red locking cap must be dismounted with a sharp screw driver and with a socket wrench SW 10 the underlying hexagonal nut has to be unscrewed. Now the working disc can be pulled from the swivel holder. The mounting of another working disc has to be done in inverse order. For the best working results the bearing of the swivel holders has to be inspected from time to time. Bearings which are loose have to be exchanged.
    Click for a larger image