How does a bicycle pump works....?

some inventions are glamorous—microchips and fiber-optic cables spring to mind. Others are quieter and more humble, but no less important. Pumps and compressors certainly fall into that category. Try to picture life without them and you won't get very far. Take away pumps and you'll have nothing to push hot water through your home central-heating pipes, and no way to remove the heat from your refrigerator. Might as well start walking too, because you won't be able to blow up the tires on your bicycle or put gasoline in your car. From jackhammers to air conditioners, all kinds of machines use pumps and compressors to move liquids and gases from place to place. Let's take a closer look at how they work!

Bicyclists use bicycle pumps on a very regular basis, but most probably never stop to think how they actually work. The purpose of the bike pump is to force air out of the valve and into your tire to increase the pressure to the appropriate level. Bike pumps use different means to do this, including hand pumping, foot pumping and CO2 cartridges. The most common means is by manual hand pumping. Here we'll look at exactly how a floor pump works.

How do pumps work?

There are really just two different kinds of pumps: reciprocating pumps and rotary pumps (which spin around). Bicycle pumps are perhaps the most familiar examples of reciprocating pumps. They have a piston that moves back and forth inside a cylinder, alternately drawing in air from outside (when you pull out the handle) and pushing it into the rubber tire. One or more valves ensure that the air you've drawn into the pump doesn't go straight back out again the way it came. It's worth noting, incidentally, that bicycle pumps are actually air compressors because they force air from the atmosphere into the closed space of the rubber tire, reducing its volume and increasing its pressure.

Intake and Release

The floor pump is basically just an air piston. The long metal or plastic shaft that stands between the base and the handle serves to hold air. When you pull the handle upwards air is sucked in through an intake valve and the piston is full of air. When you push back down on the handle, the air is pushed out of the piston, into the hose and out of the fill valve. The handle that you hold is attached to a long, thin rod that goes down into the main pump shaft. At the end of this rod, inside the pump, is a plunger assembly that creates an airtight seal so that when you push down, all air is pushed out the hose.

Valve

Bicycle pumps use several different valve types, primarily Schrader and Presta. These two types of valves correspond to the matching valve on the bike tube. Bike tubes can be purchased in either Schrader or Presta varieties. When you put the pump valve onto the tire valve and lock it in place, it allows the air exiting the pump to be pushed directly into the tube, rather than spraying out into the open atmosphere. Quality floor pumps have a pressure gauge attached, which allows you to read the tire pressure currently in your tube and pump to the desired pressure level.