Closeable nozzle

A nozzle for spraying substances, comprising:

• a nozzle body which has a nozzle mouthpiece,
• wherein the nozzle body comprises an inner pipe, said inner pipe being connected to a feed for a substance to be sprayed and comprising an inner wall, a fluid channel, an exit opening, and an outer pipe, said outer pipe being distanced to the inner pipe, being connected to a feed for a gas and comprising an exit opening,
• wherein the exit opening of the inner pipe and the exit opening of the outer pipe are arranged in a region of the nozzle mouthpiece,
• wherein the inner pipe is designed at least partly of an elastic material and a device which comprises an inlet for a fluid feed and an outlet for a fluid discharge is arranged in an annular gap between the inner pipe and the outer pipe, wherein the device has a closure position for closing the inner pipe and at least one open position, wherein in the at least one open position the substance to be sprayed can flow through at least the fluid channel, and wherein the device is designed in a manner such that a volume of the device can be changed by the fluid feed or the fluid discharge, wherein, by changing the volume of the device, the device can be brought or is brought from the closure position into the at least one open position or from the at least one open position into the closure position.