There also exist regulators which do not use the force of gravity in their operation. In this case, the rotating weights are connected by a spring, which pulls them towards each other at low rotation speeds. At higher speeds, the centrifugal force exceeds the tension force on the spring, causing the weights to rotate higher and further away from each other.

The centrifugal governor based on Watt's principle (displayed here) is the most visually appeasing example. The metal balls rotate around a vertical axis with a rotation speed proportional to that of the engine. If you were to turn in circles with a bucket of water in each hand, you would notice that the buckets swing upwards the faster you turn, or swing downwards if you are turning slowly. This is exactly what happens in the centrifugal regulator.

The Cash Acme BF Series Dual Check Valve with integrated SharkBite connections prevents polluted water from entering the potable water supply system by preventing the reverse flow of water into supply lines, and is constructed of a cast bronze body and brass union inlet connection.

The Watt regulator or centrifugal governor is a device that controls the speed of running engines. The regulator determines how much steam or fuel enters the engine based on the current running speed. The faster the engine is running, the further the inlet valve is moved towards the closed position, as seen on the animation on the right.

For steam engines, a thermal expansion or throttle valve is used to control the steam feed pressure. Closing the throttle valve lowers the pressure of the supplied steam. For combustion engines, the inlet valve regulates the amount of fuel that is delivered to the combustion chamber.

On the one hand, gravity is pulling the balls downwards. On the other hand, centrifugal forces try to force the swinging balls outwards. For each rotation speed a different balance is found between these two forces. The faster the mechanism is spinning, the higher and further apart the balls will rotate. The height of the balls is converted into a certain position of the inlet valve, using a lever mechanism, as seen in the animation on the right. This is why the inlet valve is often called a throttle valve, since the centrifugal regulator throttles the supply of fuel or steam. Steam engines were the first application sparking the development of this regulator mechanism.