Most of the time I have written about lift maintenance but as this winter and last proved, snowmaking is a very critical component of making the mountain work. So I thought I’d share a piece about the real engines behind snowmaking and their related maintenance.
Have you noticed diminished performance from your snowmaking pumps this season? Pumps that are putting out less pressure and/or running fewer guns than they could in the past? Perhaps the pumps are vibrating more than normal or their packing boxes or mechanical seals are not working well.
Due to the nature of the ski industry and snowmaking pumps, it is very critical that the condition of snow pumps be evaluated at the close of every season. Snowmaking pumps are very high performing pieces of rotating equipment and their performance can significantly deteriorate over time simply due to normal operational wear. The time required to pull, re-build and re-install these pumps will normally take a number of months and it must always be accomplished during the relatively short off-season.
Components Critical to Performance
Vertical turbine snow pumps are actually fairly simple machines with a few critical tolerances that must be within specification for the pump to function and perform properly. The components most critical to pump performance and reliability are:
- wear rings
- mechanical seals or packing boxes
The wear rings are the sealing mechanism that prevents the high pressure water coming off the impellers discharge ports from re-circulating internally back to the low pressure intake side of the impeller. The wear rings are simply statically mounted rings in the pump bowl within which the rotating rings on the intake side of the impellers run. The clearance between these static and rotating rings in a snow pump is normally in the range of .016” to .018”. If wear ring clearances opens up by as little as 25% performance will begin to deteriorate.
The sleeve bearings in the pump bowls which support and locate the shaft run even tighter clearances, typically .009” to .010” to the shaft. When the pump bowl bearings start to wear the shaft starts to move around and allow the impeller wear rings to rub against the bowl wear rings, which results in accelerated wear ring wear.
Finally, typically when the bearings and wear rings in the pumps bowls become worn, oftentimes the mechanical seal or packing box on the top end of the pump has also worn out.
Fortunately, vertical snow pumps, much like heavy diesel engines, are made such that they can be very effectively re-built over and over. Critical pump components such as shafts, bearings and wear rings can be repaired or replaced and performance will be restored, and for significantly less money than purchasing a new pump.
‘Tis The Season for Repairs
Whether your snowmaking equipment was made by Ratnik, Omnicron, Snowlogic, HKD, T/A, SMI, Demac, Lenko, York or Sufag, one thing to never overlook is the specialized high pressure pumps that power them. Ski resorts throughout the country are assessing snowmaking equipment for efficiency and to determine what needs to be repaired and replaced.
Note: This is reprint of an article found on the web. Its relevance speaks to time, now is the time to plan you pump maintenance. Call your pump supplier or your service provider to schedule the appropriate maintenance this summer, leaving plenty of time to pressurize your system in late summer/fall prep for winter and hopefully avoid any possible larger problems, which may take extended time to repair.