How Water Blasters Work Click here to print this article.
Soon after its introduction, the water gun took its place among the most popular summer toys of all time, and it's easy to see why: When you're a kid, or a kid at heart, what better way to cool off on a hot afternoon than waging an epic water battle against your friends and family?
Water guns have come a long way in the past 20 years. An ordinary squirt gun can only shoot water 8 or 9 feet, but a pump-action water blaster, like this Super Soaker CPS 1200, can shoot water more than 50 feet.
Over the years, these toys have evolved considerably. Thirty years ago, a typical water warrior was armed only with a small squirt pistol, which had a fairly short range and an even more limited ammunition reservoir. These days, you'll find an entire arsenal of water weapons at most toy stores, complete with water machine guns, water bazookas and even water grenade launchers.
Now, we'll find out how these summertime staples produce their drenching blasts. We'll trace the path of water guns from traditional squirt pistols to motorized water Uzis and finally to the pump-action water blasters that dominate the market today.
Since the pump is activated by a turning motor rather than a trigger, the design can have a slightly expanded cylinder size without making it more difficult to shoot. This extends the blast range somewhat. But the real advantage of this design is that the shooter doesn't have to keep pumping the trigger to continually shoot water. If you hold down the trigger, the motor keeps pumping, emitting a rapid series of bursts, like the continual fire of a machine gun.
Both of these gun designs are a substantial step up from the ordinary squirt pistol, but they still have significant limitations. Blasting the bazooka requires a good bit of muscle power from the shooter, and the motorized gun's water stream is still fairly weak. In the next section, we'll look at the water-gun design that revolutionized the industry, building blasts that reach 50 feet (15 m) or more.
The CPS 1200 Super Soaker has two water reservoirs, an expandable water bladder and a hand-operated pump system.
To make his idea a reality, Johnson enlisted the help of an accomplished inventor named Bruce D'Andrade. Together, D'Andrade and Johnson came up with the basic design that would become the Super Soaker.
Super Soakers are built around a pump mechanism, but moving the pump doesn't actually drive water out of the gun; it serves to build up water pressure before the blast. In the first wave of Super Soakers, you built up this pressure by pumping air directly into a single water reservoir. As you pumped in more air, it became more and more compressed and so applied greater pressure to the water inside.
In later models, you built pressure by pumping water instead of air. In the diagram below, you can see how the pieces of this sort of gun fit together.
Unlike its predecessors, this gun has two water reservoirs (labeled A and B), which are connected together via a network of tubes. To load the gun, you fill the larger reservoir (A) with water. To prime the gun for a blast, you pull the pump handle (C) in and out several times. The pump handle is connected to a long, narrow piston (D), which moves back and forth inside a cylinder (E). This pump is similar to the one in a squirt-gun pistol, and it relies on the same one-way-valve system to control the direction of water flow. The first valve (F) is positioned between the large water reservoir and the pump mechanism, and the second valve (G) is positioned between the pump and the smaller water reservoir, which feeds into the barrel of the gun (H).
Inside the body of a Super Soaker, you'll find a network of plastic tubes. This is something like the plumbing system that pumps water throughout your house.
On the upstroke of the pump cycle, when you pull the pump handle out, the receding piston pulls in water from the large reservoir above. The second one-way valve (G) keeps water from flowing up from the smaller reservoir (B). On the downstroke of the pump cycle, when you push the pump handle in, the plunging piston drives the water out of the cylinder, through the second one-way valve (G) and into the small reservoir (B). The first one-way valve (F) keeps the pressurized water from flowing back up into the large reservoir (A).
But what is all this accomplishing? In the next section, we'll put the pieces together to see how the Super Soaker builds such a powerful blast.
Super Soaker's Constant Pressure System, or CPS, pressurizes water by pumping it into a small, expandable bladder.
In the late 1990s, a new wave of Super Soaker guns came out that boasted higher pressure levels. These guns, developed by Bruce D'Andrade, feature the Constant Pressure System, or CPS. The main component in this system is a simple water bladder. This bladder is like a balloon, but it is made of much more rigid material. These guns have the same sort of pump as other Super Soakers, but the water and air are driven into the water bladder rather than into a plastic reservoir. As you pump more water in, the bladder expands, in the same way a balloon expands as you blow more air into it. When it is stretched, the bladder wants to return to its natural shape, so it applies a good deal of inward pressure on the water. When you pull the trigger and open up the passageway to the gun barrel, this pressure drives all of the water out of the gun. This allows for much more powerful water blasts than can be achieved with compressed air alone.
Photo courtesy Larami Ltd. Some of the Super Soakers in the 2001 line Click on each picture to see a larger image.
These are just two sorts of pump-based water guns. Lonnie Johnson and Bruce D'Andrade's first Super Soaker and the later addition of the water bladder have launched an entire line of water weapons. For extra ammunition, some designs hook up to a huge water reservoir that you wear like a backpack. Other guns are configured so you can shoot forward, backward and sideways at once. This has altered the world of water guns drastically. In the past, kids knew exactly what to expect when they went to the toy store for a new water gun. These days, the shelves are stocked with a wide range of new designs every summer. Unless you've been to the toy store recently, you have no idea what your neighbors might bring to the next big water fight.