A sprayer system having a trailer, which is pulled by a tractor or other towbody,and has a tank carrying liquid to be sprayed and a spray head. The trailer hasa peristalticpump mounted on a frame and driving pumping power from the wheels of thetrailer sothat the sprayer is self pumping when the trailer is pulled. The peristalticpump providesa smooth flow by providing a multiplicity of pulses of liquid produced by thepump fromthe rotation of the trailer wheels by wrapping the compressible tube of eachpump aroundan assembly of rollers which are rotated by drive wheels. The tube is wrappedat least360° around the rollers and is held stationary by being connected tofixed outlet and inletsof each pump. The tube lies side by side on at least one of the rollers ofeach assemblyand overlaps that roller.
