All Hammers shipped from the factory now are equipped with a Valve Liner. When the Valve Seat area is worn the Valve Liner can easily and quickly be replaced. This eliminates the old time consuming and expensive remachining of the Valve Seat. The Liner also allows Valve timing in the field with field tools and less than an hour’s time.
Old style Vulcan Hammers can be machined to fit the new Liner. Contact the factory for instructions.
Note: Retrofitting a cylinder for a valve liner is an operation requiring a high degree of precision and should be left to a specialist. If you want to know whether your Vulcan hammer was equipped with a valve liner from the factory, information on this is found in Vulcan Offshore Tip #7.
The Cylinder Valve Liners were developed not as much to deal with wear but to solve a manufacturing problem. In the process of casting the cylinders, the sand cores that shaped the ports to the valve liner would float in the molten metal. Since the port location required some precision, each and every hammer would have a different angular lineup of ports, which meant that the keyway for the trip in every valve stem had to be custom positioned. The valve liner insured that the ports would be in the same position on every hammer.
Below, the problem illustrated:
Raymond had already developed the precursor to this with the steam chest bushing. These were simply cast iron tubes with the surfaces and slots machined. A steam chest bushing was lightly pressed into the cylinder, as opposed to the close sliding fit of the Vulcan liner. As the tip indicates, in both cases it simplified the timing of a Vulcan or Raymond hammer considerably.