Worm gears operation

Self Wiping vocuumtight dischorge valve worm-gear-operated... 

The use of a rack-and-pinion-operated valve or worm-gear-operated valve instead of lever is suggested for valve operation in propane service if the valve is 3 inches or larger or for any service in which there is a substantial pressure differential across the valve in the closed position. 

Fluid-pressure distribution tends to close the valve. For this reason, the smaller manually operated valves have a latching device on the handle, and the larger manually operated valves use worm gearing on the stem. This hydraulic unb ance is proportional to the pressure drop and, with line velocities exceeding 7.6 m/s (25 ft/s), is the principal component in the torque required to operate the valves. Compared with other valves for low-pressure drops, these valves can be operated by smaller hydrauhc cylinders. In this service butterfly valves with insert bodies for bolting between existing flanges with bolts that... 

Worm gears of either type operating at speeds above 2400 rev/min or 610 m/min rubbing speed may require force-feed lubrication. In general, a lubricant of lower viscosity than recommended in the above the table may be used with a force-feed system. 

Warning Worm gear drives operate satisfactorily on R O gear oils, sulfur phosphorus EP oils or lead naphthenate EP oils. These oils, however, should be used only with the approval of the gear manufacturer. 

Worm gear housing After each operating period of about 1500 hours See page 180-1... 

API GL-2 Lubricants intended for automotive worm gear axles operating under such conditions of load, temperature and sliding velocity that lubricants satisfying API GL-1 service will not suffice. Products suited for this type of service contain anti-wear additives or film-strength improvers specifically designed to protect worm gears. 

The die-holder v is set on a rotary table w which is provided with a worm gear and may be rotated by a hand-operated worm. This device is desirable when extruding hollow sections with the help of an angular mandrel, so as to be able to set the mandrel into the proper relative position to the die. The runout system for the extrusions consists of a pipe, being arranged in the center line of the frame, with a cooling jacket. 

Thermal ratings of cylindrical worm gears. Thermal ratings above 100- to 200-rpm worm speed represent the input horsepower and output torque that will provide a stabilized 100°F oil-temperature rise over ambient air temperature when the machine is operated continuously. For example, if the ambient air temperature is 70°F, a reducer carr3dng rated thermal horsepower will operate with an average oil... 

Figure 11-102. A mold with a rotating core that operates during mold opening and closing. The drive gear rotates via the worm shaft, which in turn transmits the rotation to the geared core.

Some slight wear and/or pitting of the hronze gear teeth may be observed after a short period of initial operation. This condition is normal, as some initial wear is necessary for the hardened-steel worm to seat itself properly with the hronze gear. 

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