Vacuum trucks are a gigantic suction machine.
The negative pressure generated within the machine is enough to suck up anything that fits the size of the suction hose, regardless of whether the material is in a solid, liquid, or gaseous state.
In a practical application, these trucks are commonly used for cleaning sewage and drainage lines and even for hydraulic excavation.
Although the equipment can vacuum almost anything quickly, there are several things that an operator must learn in order to utilize such equipment efficiently and safely.
Maintaining Efficiency Although vacuum trucks can quickly suction anything in its path, it takes a significant amount of energy to generate a strong vacuum; therefore, it is important that the system is operated at its peak efficiency.
Following are some of the ways this efficiency can be maintained.

• Appropriate Diameter Hose - The diameter of the suction hose significantly affects efficiency.
  Theoretically, small diameter hoses offer a more superior suction power than large ones.
  This is because friction is maintained throughout the hose, so there is significantly less loss of power.
  Special consideration must be taken in the case of solids and semi- solids; the size of the hose should also be enough to accommodate the largest chunk of material to prevent clogging.
  
• Smooth Bore Hose - There are two types of hoses used in this industry - smooth-bored and corrugated.
  Both are able to do a good job; however, when considering efficiency, smooth bore hoses should be used for lengthy and heavy-duty jobs.
  Their smooth bore offers less resistance, and therefore requires less force to move debris along the hose.
  
• Maintain Uniform Diameter - As much as possible, keep the diameter of the suction hose uniform throughout its length.
  This is because a difference in diameter can create a variance in pressure.
  A smaller hose will experience greater negative pressure than a larger one; once debris gets in the larger hose, the low negative pressure may slow it down and could cause clogging.
  

Staying Safe Working around a machine that can generate a powerful vacuum is very risky.
There have been many cases where workers have suffered fatal injuries from operating this type of equipment.
Following are some of the ways that operators can work safely around such heavy-duty vehicles.

• Vigilance - Working with a vacuum truck can easily create a false sense of security.
  That is why it is important to always be aware of the dangers associated with these vehicles.
  It is important to keep in mind that a vacuum force can be generated that could literally rip a person's limb off of a body.
  During operation, always keep a safe distance from the suction tip and be aware of the location of all emergency shut off features.
  
• Grounding - Vacuuming can generate static electricity, which could trigger a spark.
  If the material being suctioned has a flash point below 140 degrees, it could potentially create an explosion.
  As a rule of thumb, a vehicle should be attached to a grounding point throughout its operation.
  
• Chemical Reactions - Chemical reactions may occur when combining two different materials together, which could result in intense heat, the release of noxious gases, and even an explosion.
  To avoid a chemical reaction, always clean the holding tank in between jobs that involve different liquids and other material; maintain a record of the materials being transported.
  

In summary, vacuum trucks are truly an engineering marvel.
They have greatly improved the process of sewage and drain cleaning as well as being used for drilling known as hydro excavation.
Hopefully this article has provided some helpful information as to how this equipment can be used both safely and productively!