Pneumatically operated Shot Peening and Shot Blasting Machine

Abstract

A pneumatically operated shot peening or blasting machine is designed to be convenient and mobile to be used to treat newly cut threads of oil tools in a contained and controlled manner. The machine uses compressed air and electric power to spray tiny Carbon Steel or Stainless Steel round balls to impart small indentation on the surface of the threads, or to clean and remove material from the surface of the tool. The indentations in shot peening puts the metal surface in compression creating stress zone and plastic deformation to relieve fatigue and prevent premature fractures and stress corrosion cracking. The inventive machine is designed to follow Shot Peening Standards such as MILS-13165B, J441, and AMS 2430 or other standards as apply.

What is claimed is: 
     
         1 . A shot peening or shot blasting machine, comprising:
 a source of compressed air;   a lance for carrying spheroidal media, which is connected to the source of compressed air and which is connected to a device for rotating the lance at a predetermined speed, the device also able to move forwards and backwards between two adjustable predetermined positions;   a nozzle, connected to the lance, for directing the spheroidal media onto an axial length of the tool defined by the two adjustable predetermined positions;   the nozzle and tool being contained within a shot media container;   whereby the process of shot peening or shot blasting is easier, safer and more environmentally friendly because the shot media is controlled and contained.   
     
     
         2 . The shot peening or shot blasting machine of  claim 1  wherein the tool is a length of pipe having an end with external threads extending a predetermined axial length and wherein the nozzle is constructed and arranged for splitting the spheroidal media into two streams so that external threaded end of the pipe can be impacted with the two streams of media simultaneously to enhance coverage and provide 100% coverage in a single pass as the nozzle is moved by the device between the two adjustable predetermined positions, which are selected to correspond to the axial length of the external threads. 
     
     
         3 . The shot peening or shot blasting machine of  claim 1  wherein the tool is a length of pipe having an end with internal threads extending a predetermined axial length and wherein the nozzle is constructed and arranged for directing the spheroidal media onto the internal threaded end of the pipe as the nozzle is moved by the device between the two adjustable predetermined positions, which are selected to correspond to the axial length of the internal threads. 
     
     
         4 . The shot peening or shot blasting machine of  claim 1  wherein the nozzle is a three way nozzle which can be selectively configured to direct spheroidal media between a split stream configuration or a single stream configuration and wherein the split stream configuration is for shot peening or shot blasting an externally threaded end of the tool, and wherein the single stream configuration is for shot peening or shot blasting an internally threaded end of the tool. 
     
     
         5 . The shot peening or shot blasting machine of  claim 1  wherein the spheroidal media is selected from the group consisting of carbon steel, stainless steel, glass and ceramic media. 
     
     
         6 . The shot peening or shot blasting machine of  claim 1  wherein the spheroidal media shot size is selected from the group consisting of 0.18 mm, 0.28 mm, 0.42 mm, 0.58 mm, 0.71 mm and 0.84 mm diameter shot media. 
     
     
         7 . The shot peening or shot blasting machine of  claim 1  wherein the machine has an adjustable volume of compressed air of between 81 CFM to 196 CFM. 
     
     
         8 . The shot peening or shot blasting machine of  claim 1  wherein the machine has an adjustable pressure of compressed air of between 30 psi to 120 psi to achieve the desired intensity. 
     
     
         9 . The shot peening or shot blasting machine of  claim 2  wherein the nozzle has two ends having blast nozzle ends which can be selected to adjust the angle of spray of the shot media from the group consisting of 45°, 60°, 90° and 135 reverse degrees. 
     
     
         10 . The shot peening or shot blasting machine of  claim 1  in which the lance is rotated at 20 rpm to enhance coverage while achieving uniform compression and in which the lance is carried by a motorized lance cart which moves between the two predetermined positions at 0.125 meters per second. 
     
     
         11 . The shot peening or shot blasting machine of  claim 1  wherein the machine has a pneumatic vertical height adjustment to adjust the lance and nozzle so it is centered on a tool axis. 
     
     
         12 . The shot peening or shot blasting machine of  claim 2  wherein the nozzle directs the two streams simultaneously onto the tool at points 180° apart to achieve 100% coverage with a single pass. 
     
     
         13 . The shot peening or shot blasting machine of  claim 1  wherein the device rotates the lance using an electric motor. 
     
     
         14 . The shot peening or shot blasting machine of  claim 8  wherein the device uses an electric motor to move forwards and backwards between the two predetermined positions. 
     
     
         15 . The shot peening or shot blasting machine of  claim 9  wherein the device includes a control device for setting the number of passes the machine makes between the two predetermined positions and the rotation speed of the lance. 
     
     
         16 . The shot peening or shot blasting machine of  claim 1  wherein the machine is carried on a wheeled cart so the machine is mobile and can be taken to where tools need to be treated. 
     
     
         17 . The shot peening or shot blasting machine of  claim 1  wherein the shot media container has an opening in the bottom which allows used shot media to be collected, screened to remove broken shot media and reused. 
     
     
         18 . A valve for shot peening or shot blasting, comprising:
 a section for carrying shot;   a junction section having at least two split sections for splitting the shot into at least two streams of shot;   rotatable end sections connected to each of the at least two split sections for directing the shot either inwards or outwards, whereby either an external surface of a tool can be shot peened or shot blasted, or an internal surface of a tool can be shot peened or shot blasted.   
     
     
         19 . The valve for shot peening or shot blasting of  claim 18  wherein the junction section is Y-shaped having two split sections, with the two ends of the Y forming a curved crescent shape. 
     
     
         20 . The valve for shot peening of  claim 18  in combination with a machine for shot peening or shot blasting, further comprising:
 a source of compressed air, which is connected to the section for carrying shot; 
 spheroidal peening media which is directed by the compressed air through the section for carrying shot, and which is split into two streams by the Y-section. 
 
     
     
         21 . The combination of  claim 20  further including rotation apparatus for rotating the valve to treat the threads of the pipe around the entire circumference of the pipe with the two streams of shot. 
     
     
         22 . The combination of  claim 21  further including axial movement apparatus for moving the valve along a predetermined axial length of the pipe to be peened or blasted. 
     
     
         23 . The valve for shot peening or shot blasting of  claim 18  wherein the junction section has three split sections, two outside Y-nozzle sections and one center section, and where a carbide insert can be inserted to selectively direct the shot media into the two outside Y-nozzle sections for treating external threads or to direct the shot media into the center section for treating internal threads. 
     
     
         24 . The valve of  claim 23  wherein the junction point is reinforced where the splitting of the streams occurs to length the useful life of the nozzle. 
     
     
         25 . The valve of  claim 24  wherein the junction point is reinforced with tungsten carbide. 
     
     
         26 . A shot peening or shot blasting machine, comprising:
 a source of compressed air;   a lance for carrying spheroidal media, which is connected to the source of compressed air and which is connected to a device which move forwards and backwards between two adjustable predetermined positions;   a nozzle, connected to the lance, for directing the spheroidal media onto an axial length of the tool defined by the two adjustable predetermined positions to treat the axial length of tool;   a rotation device for rotating the tool;   the nozzle and the axial length of tool to be treated being contained within a shot media container;   whereby the process of shot peening or shot blasting is easier, safer and more environmentally friendly because the shot media is controlled and contained.