Search results
Results from the WOW.Com Content Network
Its construction and principle of operation is simple. It consists of a titanium filament through which a high current (typically around 40 A) is passed periodically. This current causes the filament to reach the sublimation temperature of titanium, and hence the surrounding chamber walls become coated with a thin film of clean titanium.
Single-stage vacuum pumps typically produce vacuum to 35 torr (mm Hg) or 47 millibars (4.7 kPa), and two-stage pumps can produce vacuum to 25 torr, assuming air is being pumped and the ring-liquid is water at 15 °C (59 °F) or less. Dry air and 15 °C sealant-water temperature is the standard performance basis, which most manufacturers use for ...
In some purposes, the bag encloses the entire material, or in other purposes, a mould is used to form one face of the laminate with the bag being a single layer to seal to the outer edge of the mould face. When using a tube-shaped bag, the ends of the bag are sealed and the air is drawn out of the bag through a nipple using a vacuum pump.
In the field of oil regeneration and re-refining, vacuum pumps create a low vacuum for oil dehydration and a high vacuum for oil purification. [44] A vacuum may be used to power, or provide assistance to mechanical devices. In hybrid and diesel engine motor vehicles, a pump fitted on the engine (usually on the camshaft) is used to produce a vacuum.
Vacuum dryer is the equipment with the help of which vacuum drying is carried out. Vacuum dryers are sometimes made up of cast iron, but most are made of stainless steel, so that they can bear the high vacuum pressure without any kind of deformation. The oven is divided into hollow trays which increases the surface area for heat conduction. The ...
External vacuum sealers involve a bag being attached to the vacuum-sealing machine externally. The machine will remove the air and seal the bag, which is all done outside the machine. A heat sealer is often used to seal the pack. Typically these units use a dry piston vacuum pump which is often considered a "maintenance-free" pump.
Electric breast pumps are larger than manual ones, but portable models are available (e.g. in a backpack or shoulder bag). Some models include battery packs or built-in batteries to enable portable operation of the pump. Some electric pumps allow multi-user operation but recommend an accessory kit for each user to maintain cleanliness. [26]
Wrigley's forceps, named after Arthur Joseph Wrigley, are used in low or outlet deliveries (see explanations below), [5] when the maximum diameter is about 2.5 cm (0.98 in) above the vulva. [6] Wrigley's forceps were designed for use by general practitioner obstetricians, having the safety feature of an inability to reach high into the pelvis. [6]