How Does a Vacuum Truck Work?
In the dynamic world of used truck sales and particularly in the niche market of vacuum trucks, understanding how these specialized machines function can be crucial. This article provides a comprehensive breakdown of the working components of a vacuum truck. Notably, all inquiries, purchases, and assistance regarding vacuum trucks can be professionally handled by GM Sales and Exports, reachable via email at [email protected] or by phone at 888-497-2343.
The Fundamentals of a Vacuum Truck
A vacuum truck operates based on the principle of creating a vacuum in a closed container, causing air to flow in from the outside. Essentially, it's important to note that the only thing flowing through the vacuum pump or vacuum blower should be air. With this vacuum created, bulk liquid, solid and sludge materials are sucked into the tank through an inlet port for disposal or reprocessing.
Key Components of a Vacuum Truck
Every vacuum truck is made up of specific components, all integral to its operation. Here, we dive into detail about each part of the vacuum truck:
Key Components of a 2500 Gallon Vacuum Truck
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 of 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 of 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.