Speed controller with scales

摘要

A speed controller with scales according to the invention is used to adjust the amount of an air flow thereby to control the amount of a chemical liquid sprayed. The speed controller includes a housing, a controller body and a transparent tube. The controller body is partly inserted in the housing and has a rotary button located at one end thereof and outside the housing. The rotary button has a slot and an indicator thereon, wherein the indicator is located at one end of the slot. The transparent tube, having a vertical scale on the side thereof and a circular scale on the top circumference thereof, encloses the rotary button. In the invention, the position of the rotary button can be determined by reading the vertical scale and the circular scale so as to precisely control the amount of a chemical liquid sprayed, thereby increasing yield and improving engineering analysis.