Spiral grooves

A low melting (5°C) gallium—indium—tin alloy has been the choice for small spiral-groove bearings in vacuum for x-ray tubes at speeds up to 7000 rpm (71). Surface tension 30 times that of oil avoids leakage of the gallium alloy from the ends of the bearings. 

The finish of flange facings varies with the manufacturer. For raised-face or male mating surfaces the finish usually consists of a continuous spiral groove formed by a round-nosed tool or a V tool (serrated finish). Female surfaces are smooth-finished (i.e., without definite tool markings). Other finishes are concentric-grooved, lapped, or mirror (cold-water). The latter two are usually for application without gaskets. 

Basically, the purpose of drill collars is to furnish weight on bit. However, both size and length of drill collars have an effect on bit performance, hole deviation, and drill pipe service life. Drill collars may be classified according to the shape of their cross-sections as round drill collars (conventional drill collars), square drill collars, or spiral drill collars (drill collars with spiral grooves). 

Square drill collars are used to increase the stiffness of the drill string and are recommended for drilling in crooked hole areas. The spiral type of drill collar is used for drilling formations in which the differential pressure can cause sticking of drill collars. The spiral grooves on the drill collar side reduce the area of contact between drill collar and wall, which considerably reduces the sticking force. 

The outer wall of this holder is provided with a spiral groove for insertion of a heating wdre. The holder is installed into a pressure vessel via a few screw connections, giving a gas-tight system. Quartz glass inspection flanges at both ends of the vessel serve for pyrometric inspection to judge the catalyst temperatures at the stack inlet and outlet. 

A spiral coil of Teflon, or a spiral groove on a stainless steel surface covered with quartz, is used as a flow cell in the CL detector. These cells are placed in front of a photomultiplier tube (PMT), which detects photons emitted by the CL reaction. The cell volumes are generally in the range of 60-120 J.L. 

Raw materials 2, Inner shell 3, Inner shell with welded bottom 4, Spiral groove inner shell 5, Wrapping bands onto inner shell 6, Dimensions inspection 7, Assemble closures 8, Hydrotest 9, Transport to destination. 

The design of the spiral column assembly is shown in Fig. 1. Fig. lA shows a full view of the column assembly, which can be mounted on the type-J multilayer coil planet centrifuge (P.C., Inc., Potomac, MD, USA). The column components are illustrated in Fig. IB. The column consists of a pair of flanges (one equipped with a gear), nine disks with spiral grooves, and ten Teflon sheet septa. The drawing, and dimensions for each component are illustrated in Fig. 2A-E. 

The width of the spiral groove becomes the depth of the channel and the depth becomes the width of the channel when assembled. 

Riffle. 1. (Fire-arms,) A fire-arm having the bore spirally grooved, so as to impart a rotary motion to tlie bullet and cause it to keep one point constantly in front during its flight. 

Ri fling Ma-chine A tmodiinc for making the spiral grooves hi the barrels of guns. 

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