IntroductionHow many times have you heard: "The windows on the school bus are foggy and there's no heat on the bus. My kids are cold!" Clearly, you know there is a problem with the mechanics of the school bus. Unfortunately, you already know the culprit; the booster pump has failed again. Yet another bus has to be taken out of service for expensive repairs, which cost time, materials, and labor.
Wouldn't it be nice if you could completely eliminate this recurring problem? You can, with brushless. seal-less pumps (School Bus or Heavy Duty Bus), but how does this benefit you?
Although the initial acquisition cost of the pump is higher (see figure 1), the annual maintenance cost for this application is reduced by 75% for the Life of the bus compared to a standard booster pump, saving you money over the Life of your fleet. Without the maintenance costs associated with traditional booster pumps, you'll be able to put that money back into your fleet for something other than repairs.
Brushless Motors Provide No Physical Contact
Let's talk about motor technology. Standard booster pumps leverage a brush style DC motor that can be inefficient due to perpetual physical contact with the shaft. This constant contact creates a point of failure within the motor (see figure 2). Additionally, the constant switching action of the commutators, creating and breaking inductive circuits, creates a great deal of electrical and electromagnetic noise.
However, brushless motors commutate by electronically switching stator fields through rotor position sensing. In other words, the motor is more efficient, because it does not have contacting electrical connections (see figure 2). Brushless motors have a long lifespan with no maintenance required, unlike brush based motors making them the choice of heavy duty transit bus manufacturers.
Seal-less Pumps Will Not Leak
Another reason coolant pumps fail, can be directed towards the sealed design of the pump. Mechanically sealed pumps are designed to lubricate and cool themselves by leaking small amounts of fluid as they operate. In doing this, coolant seeps into the pump's operating environment, leading to process inefficiency and shorter life. Mechanical seal pumps have a tendency to quickly wear down, lose their effectiveness, and leak greater amounts of liquid through their seals. Obviously, this "spillage" decreases environmental and work site safety while adding avoidable expense to the overall life of a school bus.
In comparison to traditional booster pumps, the process used to seal the pump is different. A seal-less magnetic drive pump has neither mechanical seals nor packed glands (see figure 3). In place of the dynamic seals, you find a shroud (static containment shell) that forms a liquid pressure boundary. This containment shell forms a completely sealed enclosure through which the fluid being pumped cannot leak. Thus,magnetically sealed pumps do not inherently leak.
So when you hear: "The windows on the school bus are foggy and there's no heat on the bus. My kids are cold!" Don't fret; turn to a brushless seal-less booster pump to reduce cost, maintenance, and downtime for your fleet.
At AMETEK Dynamic Fluid Solutions, we understand you’re looking for more than just an off-the-shelf part or one-time solution. You need a true technology partner who understands your engineering challenge that is focused on you, providing customized, collaborative solutions. We’ll also provide you with excellent customer service for a great total experience.