The invention relates to a pneumatic pressure regulating assembly. The assembly includes a cylindrically shaped housing having a top or cover portion with holes therein. A spindle member extends through and above the housing with the spindle portion above the housing being hollow and having an inlet opening in fluid communication with the hollow interior. A dish shaped member having a central opening is slidably mounted on the spindle member. The dish shaped member has a flange engageable with the top portion of the housing and being in surrounding relation to the holes in the cover portion. The dish shaped member is raisable by air flowing through the housing and the holes in the cover thereof so as to allow a portion of this air to be blown off and the remaining portion of the air to enter the inlet opening of the spindle member. The dish shaped member has a predetermined weight and the pressure is regulated by reason of the dish shaped member assuming different vertical positions which keeps the pressure constant by varying the amount of air blown off.