By Bradley Kramer
Vacuum excavators are versatile machines that can aid in a variety of construction jobsite applications, from safe digging around facilities to spoils removal. However, there are a number of critical components of the trailer and truck-mounted vacuum excavators to keep an eye on to get the most out of your machine.
In addition to daily maintenance check points, such as fluids and filters, the key maintenance points are the blower, water pump, hydraulic system, chassis, grease points and air flow system, according to Ben Schmitt, Westech Vac Systems General Manager.
Craig Svandrlik, West Coast Industrial Sales Manager for RamVac, provided a quick checklist of key items to check:
- Final filter needs to be free of debris to breathe air through the blower.
- Check oil on chassis, blower, transfer case and water pump.
- Inspect cyclones for material and keep them cleaned out.
- Inspect transition from boom into debris tank and be sure it’s free of rock or other debris.
- Inspect boom and rear door seals for vacuum leaks due to poor sealing.
Maintain your equipment regularly and service issues as they happen, Svandrlik adds.
Schmitt and Svandrlik sat down and provided a number of tips to help vacuum excavator owners and operators keep their machines running strong.
Why is regular maintenance important for vacuum excavators?
Svandrlik: To prolong the life of your investment and ensure the unit works at its peak performance. Your excavator is the tool which allows you to do your job every day. If your truck is not working as efficiently as possible, you are losing money due to decreased productivity.
Schmitt: A vacuum excavator is like a fire truck, when it’s called on, it’s usually very important and the equipment must be functional. In order for the equipment to be reliable and ready at a moment’s notice, the equipment must be maintained and inspected. Additionally, many of the components on a vacuum excavator are costly, and routine maintenance can prevent a small problem from turning into a large, expensive problem. Routine maintenance also ensure the equipment lasts as long as possible and preventing premature failure.
Schmitt: The blower is the heart of the vacuum system. It is responsible for creating the air flow and vacuum for the vacuum excavator to do work. Blowers work on very tight tolerances to create the high vacuum levels blowers are known for. Any degradation to these tight tolerances will degrade blower performance over time. We like to teach users that a blower will never be as good as it was the first day as their performance slowly deteriorates overtime due to wear and tear of the lobes. The better protected the blower lobes are from wear, the long and better performing the unit will be. Additionally, blower turn at a high rate of speed to create the high airflows. Because of this, the rotating components must be adequately lubricated with oil. It’s imperative the blower oil levels are kept in the optimal range and blower oil changed at regular maintenance intervals. Much like your car engine, blower oil loses its viscosity and provides less protection to the rapidly turning components over time.
Svandrlik: Do not let material or water pass through your filters or the blower. Protect your blower, do not overload your truck. Overloading can be avoided by utilizing machine options the help alert the operator when the debris tank is full and other features that automatically cut off your vacuum when the debris tank is full.
Svandrlik: Do not crank down on unloader valves to increase water pressure, instead use a nozzle the allows for higher GPMs.
Schmitt: The water pump on the hydrovac need to have their oil levels checked as well as ensuring the water flow to them is sufficient. Any restriction in the water flow to the water pump can cause the water pump to cavitate. Water pump cavitation causes excess wear and ultimately failure of the water pump overtime. The water pump oil lubricates the moving gears that control the piston pumps. Much like your automobile, this oil will break down overtime and need to be changed. Routine oil changes should be performed.
Schmitt: The filtration system of a vacuum excavator typically is composed of a particle separation device, such as a cyclone, and a fine filter media such as paper filters. Blower systems used in vacuum excavators work on very tight clearances and tolerances. Vacuum is produced by the blower’s lobes rotating in close proximity to each other – this space is often less than the thickness of a piece of paper. Any material that passes through the blower will cause wear and degradation of the blower lobes, thus enlarging the clearance and reducing the vacuum capability of the blower. Because of this, the filtration system of the blower must be routinely cleaned and maintained. The cyclone should be cleaned and emptied daily. Additionally, the cyclone should be inspected for any wear or damage. Cyclones, by their nature, are high wear components and can wear through over time. Any wear through will effectively negate the benefit of the cyclone and cause the material to carryover into the paper filters. Furthermore, any damage to the cyclone, dent, crack, etc, will impact the efficiency of the cyclone causing more material carryover.
The last line of defense for the blower is the paper filter, usually mounted right at the blower intake. The filter is designed to filter any small debris particles left in the air stream after the cyclone. These filters usually have filtration ratings down to 5 micron and sometimes even less which protect the tight clearances of the blower. Damage to this filter can allow larger particles of debris to become vacuumed into the blower and cause performance degradation and, even worse, catastrophic failure of the blower.
Svandrlik: Strong airflow makes all the difference if you want to pull from great depths or lift great weight. This is the difference between drinking through a standard drinking straw or a coffee stirrer.
Svandrlik: Rotate and change the position of your vacuum hose. This keeps debris from wearing a hole in a single location and extends the life of your vacuum hose.
Schmitt: Most importantly for vacuum hose is to periodically rotate the hose to change the wear pattern and extend the life of the hose itself. Additionally, routinely checking for any bulges, cuts, or sign of failure is recommended. A damaged hose can lead to many additional issues.
Svandrlik: Leave the rear door open over the weekend or during longer periods of time between jobs. This will allow the rear door seal to rest and help dry out the debris tank.
Schmitt: The most important areas to maintain are the rear door seal and float ball cage and seat. The rear door seal should be checked daily and cleaned after every load of debris is offloaded. Damage to the rear door seal could/will result in a leaky rear door. Additionally, the float ball cage and seat should be inspected and cleaned after each offload as well. The float ball and seat ensure that when the debris tank is full that vacuum shuts off and does not continue vacuuming material over into the cyclone, final filter and then the blower.
Handguns and Water Lances
Schmitt: Hydrovac units operate on high pressure, as high as 3,000 PSI and higher in some applications which can be dangerous when used improperly or if there is a component failure. The handgun is equipped with a shutoff that will automatically shut the high-pressure water off when the handle is released. This prevents the wand from spraying water without the operator having control of the wand. Should there be an issue while working and the operator drops the wand, the water system will shutoff protecting the operator from additional danger.
Water lances should be inspected and cleaned. The connections can become dirty or corroded over time making them more difficult to connect and disconnect. On a jobsite where time is the essence, ensuring the lances are able to be quickly connected and disconnect will save time and frustration.
Svandrlik: Inspect handguns for cracks in the plastic handle to avoid injury. Also, try to avoid hitting large rocks with the head of the rotating nozzles, as it could jam the tip and limit rotation.
Bradley Kramer is a contributing staff editor to Utility Contractor.Tags: Vacuum Excavators