De Laval's impulse turbine is simpler, less expensive and does not need to be pressure-proof.

A stage of an impulse turbine consists of a nozzle set and a moving wheel.

This is used to solve the problem of high blade velocity in the single-stage impulse turbine.

It is a three stage pressure compounded impulse turbine.

Each stage acts as a velocity compounded impulse turbine.

(Later, impulse turbines were developed which did not use swirl).

The arrangement consists of a number of simple impulse turbines in series mounted on a common shaft.

Each of the simple impulse turbines would then be termed a "stage" of the turbine.

Some impulse turbines use multiple water jets per runner to increase specific speed and balance shaft thrust.

Newton's second law describes the transfer of energy for impulse turbines.