An air compressor includes a valve plate with cooling fins and a piston also having cooling fins. The valve plate includes an integral and angled valve plate outlet. The angling of the valve plate outlet reduces turbulence and improves compressed air flow. The pump frame of the gas compressor includes a lipless bearing bore, decreasing the distance between the portion of the frame supporting the bearing and the piston. The pump frame is flat such that a portion of the cylinder is over a portion of the motor. The flatness of this arrangement increases the strength of the pump frame. The piston bearing bore includes two clamping structures having screw holes. Each screw hole is formed from a series half-cylinder or barrel portions, which individually do not form the complete circumference of a hole. Such a screw hole does not require a core pull on casting, lowering manufacturing costs. The piston includes a piston seal which is angled with respect to the piston. The piston head is machined at an angle to lower the amount of dead space near the top of the cylinder. The compressor includes a fan which operates efficiently at different speed settings. The fan is a radial fan including two sets of fan blades, a set of inner flat fan blades which operate most efficiently at a first range of speeds and a set of outer curved fan blades which operate most efficiently at a second range of speeds. The fan blows air through the compressor in a novel air cooling pattern, propelling air axially upward along the outside of the cylinder, increasing cooling efficiency.
1. A radial fan comprising:
a first set of straight paddle fan blades which are configured when rotating to direct air primarily in a radial direction relative to rotation of the fan and are most efficient at a first set of operating speeds; and
a second set of forward curved blower wheel fan blades which are configured when rotating to direct air primarily in a radial direction relative to rotation of the fan and are most efficient at a second set of operating speeds.
2. The radial fan of claim 1 , wherein the second set is positioned peripherally outside of the lint set.
3. A radial fan comprising:
a first set of straight paddle fan blades which are configured when rotating to direct air primarily in a radial direction relative to rotation of the fan; and
a second set of forward curved blower wheel fan blades located peripherally to the first set of fan blades and which are configured when rotating to direct air primarily in a radial direction relative to rotation of the fan.
4. The radial fan of claim 1 , wherein the first set of operating speeds is approximately 1,500 to 2,500 revolutions per minute.
5. The radial fan of claim 1 , wherein the second set of operating speeds is approximately 3,000 to 4,000 revolutions per minute.