Vacuum trucks are used to clean pipes and remove unwanted sediment or materials from wastewater
plants, drilling sites, septic tanks and so on. It works by creating a vacuum in the tank. A vacuum pump
is engaged and that pulls air through a filter. The filter removes debris, whereby protecting components
of the pump. A vacuum pump uses centrifugal force created by rotary veins within its case. The veins
are typically made of Kevlar or something similar and pumps usually have six or more of them. To
ensure that you do not overfill your tank, there are primary and secondary shut-off’s that are made of a
rubber seat and steel ball enclosed in a cage. The secondary shut-off is also a moisture trap and should
be drained and cleaned after every timer the tank is unloaded. The pump and motor combination is
the most common platform on vacuum trucks and it consists of a vacuum pump and motor that runs the
pump. Others use a power take off (PTO) mounted on the transmission that distributes power to the
pump. The transmission is protected by a coupling and sleeve system if the vacuum pump fails. There is
also a vacuum relief valve along with a pressure relief valve that protect the vacuum tank from too much
vacuum or pressure at any given time.
The amount of air that a pump moves through the pump, measured in cubic feet per minute (CFM),
determines the pump’s rating. This is also the means of determining a pump’s compatibility with a
particular tank and truck. Find out exactly how many RPM’s your vacuum pump should be set to run
at in the owner’s manual but most range between 1,100 and 1,300. There are fan-cooled vacuum
pumps and liquid-cooled ones. The manufacturer will list in the owner’s manual what pump oil to
use. It will also tell you what flushing fluid to use and how often to maintain or service it. Your pump’s
performance is enhanced by regular use of the flushing fluid as it removes and prevents deposits. If not
done regularly, these can form on the pump veins and case and the pump’s performance will suffer.
Vacuum pumps come equipped with an oil-catch muffler. These are designed to catch most of the
used oil that escapes from the pump and it also serves to reduce noise output. It is normal to see some
smoke coming from the muffler since it only catches about ninety-five percent of the oil. It should also
be emptied daily so keep that in mind! Individual, specific recommendations pertaining to pump size
relative to tank size vary by manufacturer. The truck’s gross vehicle weight (GVW) generally determines
the appropriate tank size. Carefully review the area that you are going to service. This, along with the
money you have set aside for this investment, should determine the size and type of pump, tank and
truck that will best serve your business goals!
