How Does a Vacuum Truck Work?
This diagram shows how a vacuum pump truck works. Keep in mind that only thing that should ever flow through a vacuum pump or vacuum blower is air. The pump creates a vacuum in the tank and the vacuum does all the work. Call LMT at 309-932-3311 if you have any questions or need help with an existing vacuum truck or a new design. We're standing by to build your next vacuum tank.
1) Tank Can
Center cylinder of the tank body. Rolled sheet of steel or stainless steel usually 1/4" inch thick.
2) Tank Head
End cap of the tank body. At LMT, we use a flange and dish (F&D) process to form our tank heads. Constructed of same material as can.
3) Discharge Port
Generally 3", 4" or 6" pipe connected to a lever, butterfly or ball valve.
4) Inlet Port
Generally 2", 3", 4" or 6" pipe connected to a lever, butterfly or ball valve. Inlet port is typically smaller than the discharge port to assure passage of any large object.
5) Sight Eyes
Used to view load level of tank. Generally 2", 3" or 5". Sight eye bowl constructed of glass or plastic and are removable for easy cleaning. Large tanks generally have three 5" sight eyes at 1/2, 3/4 and full levels.
6) Vacuum/Pressure Gauge
Simple gauge indicating the level of vacuum or pressure in the tank.
7) Manway/Hatch/Portal
Tank access port ranging from 12" to 36" in diameter. Essentially for cleaning. Typically located on the top or rear of tank.
8) Vacuum Relief Valve
Safety feature used to regulate maximum vacuum level in the tank. Reduces risk long term tank fatigue and potential for tank collapse. Also allows air to circulate through tank to cool vacuum pump. Mounted as close to the pump as possible.
9) Pressure Relief Valve
Safety feature used to regulate maximum pressure level in the tank. Reduces risk long term tank fatigue and potential for tank collapse.
10) Primary Shutoff
The first line of defense preventing tank contents from entering the pump, available in a variety of sizes and variations. Rated by CFM to be paired appropriately with vacuum pump.
11) Float Ball
Floats to top of tank when full. Constructed of stainless steel or rubber coated plastic.
12) Ball Seat
Gasket-like ring above the float ball creates a seal when tank reaches capacity.
13) Secondary Shutoff
Second component inline preventing tank contents from entering the pump. Available in a variety of styles & sizes. Rated by CFM to be paired appropriately with vacuum pump.
14) Vacuum Pump
Rotary vane vacuum pumps create a vacuum in the tank. The pump uses 2 to 8 replaceable sliding vanes to move the air. The vanes require constant lubrication using a reservoir and regulated delivery system. Each pump is designed to turn in only one direction - clockwise (CW) or counter-clockwise (CCW). Pumps are rated in cubic feet per minute (CFM) and range from 30 to over 500 CFM.
15) Oil Catch Muffler/Oil Separator
Reduces pump exhaust noise level and separates blow-by pump oil for disposal. Appropriately sized to vacuum pump to prevent oil from blowing out of the exhaust.
16) Tank Rails
Supports the bottom of the tank. Available straight (shown) or tapered/sloped.
