One of the regular challenges of operating a vacuum truck is getting the vacuum hose to the area that needs to be pumped. Operators regularly pull up to jobs with poor access to the work area and have to find solutions to get to it. Generally speaking – the closer the truck is to the thing being pumped – the easier it will be to pump. Typically, operators have used combinations of hoses varying in size and articulation to get to a work zone – but sometimes if the truck can be maneuvered close enough to the area – a boom mounted hose can be used. The boom mounted option has clear advantages to hose assemblies, mainly that the system can be operated using a remote control to move the boom and position the orifice where needed. As a result, we are seeing more boom mounted systems on vacuum trucks in many industries.
These boom mounted systems require a single, sealed, and rotating mounting point which allows the boom to turn without twisting the main hose or any of the attached device hoses or cords. This is where the boom swivel is required. It provides an extremely strong mounting point from which the entire boom assembly is attached to the truck by, and pivoted and rotated from.
Since all the weight of the boom (sometimes in excess of 1000 lbs) is held by the swivel, it must be extremely robust and made of high-grade hardened steel with an additionally hardened interior ball bearing track – and it must do this while being able to rotate and carry the material being pumped through the middle of it into the vacuum tank, all while under vacuum pressure.
Typically, the boom swivel is the most common failure point on a boom assemblage due to the high amounts of stress and dynamic forces being applied to it, due to the previously mentioned fact that it must maintain a vacuum seal under these forces and movements. When the boom is fully extended, being moved, and loaded up under the weight of the material being conveyed the boom swivel comes under great amounts of added stress beyond the resting weight of the assemblage. This is what we call “dynamic forces” – any boom is subject to great amounts of them. So, with all this in mind, what makes a good boom swivel?
What makes a ‘good’ boom swivel
All swivels are made up of a slewing ring or slewing bearing and usually married to a worm drive. The slewing ring is the rotating part of the swivel and will have one static ring and one rotating ring. This constitutes the rotating seal. The static ring is attached to the truck, and the rotating ring sits outside of the static one joined by bearings within a split track between the two rings. (picture) The static ring and the outer toothed ring are put together and secured by several stainless-steel ball bearings which sit in a half track in each ring.
Because all the weight of the assembly rests on the bearings, which subsequently sit in the bearing track, the bearing track is hardened using a laser process to prevent typical wearing out of the bearing track. This provides an additionally hardened surface within the already hardened ring, which has been shown to greatly reduce typical wear and increase the life of the swivel. Additionally, as with most of our boom swivel configurations, the swivel is powered independently by a hydraulic worm drive which has the torque to move and hold the boom at maximum extension. This worm drive runs against the toothed outer ring and must be aligned or ‘lashed’ properly to ensure proper and even gear wear.
At Fruitland we build many different custom boom swivels for our customers and have been doing so for years. Our slewing rings and swivel assemblies’ benefit from years of purpose-built design tested by trial and error in the field. Each boom swivel slewing ring is specifically designed with a custom-built moving wiper seal which maintains high vacuum under heavy loads while moving and pivoting.
Watch a time-lapse of the marrying process here.
Benefits of a Boom-mounted hose:
In the vacuum truck industry, a boom-mounted hose assembly:
- Gets the vacuum hose to the area that needs to be pumped.
- Can be operated using a remote control
- Turns without twisting the main hose or any of the attached device hoses or cords.
Is the single, sealed, rotating mounting point that attaches the boom assembly to the vacuum truck. It is also the point at which the boom assembly is pivoted and turns.
A boom swivel must be;
- Extremely robust
- Made of high-grade hardened steel
- Build with a laser hardened interior ball bearing track
- Able to rotate and carry the material being pumped through the middle of it.
A Boom swivel is the most common failure point on a boom assemblage due to the high amounts of stress and dynamic forces being applied to it. For that reason, it is crucial to choose a high-quality boom swivel for your truck.