Bosch Air tools for industry catalog Page 109
Commercial customer offer**Top sellers from Bosch Blau
Air technology guide | 109 The compressed-air system First link in the chain Although Bosch does not manufacture any compressed- mum pressure (e.g. 12 bar) is reached and is switched air systems, we should still discuss the basic structure of on when a pressure falls to a minimum value (e.g. 8 bar). this kind of system (please obtain more detailed informa- During this time span, the pressure tank and the feed tion from the compressor manufacturer). lines act as a reservoir for the tools. Compressor Idle control The following four types of compressor are usually used: In the case of medium to large piston compressors, ▶ Piston compressor: Depending on the pressure this usually takes place by opening and closing sliders range, there are one-stage or two-stage piston com- or valves. This prevents continuous deactivation and pressors, e.g. one-stage for a final pressure of up to activation of the electric motor and the associated approx. 10 bar, two-stage for a final pressure of up high starting current. to approx. 17 bar ▶ Rotation compressor Bypass on-off control ▶ Screw-type compressor The bypass on-off control on small to medium-sized ▶ Turbo compressor compressor systems is performed by means of a pressure monitor, which switches the electric motor Pressure tank control on and off depending on the tank pressure. The compressed air conveyed by the compressor is The following rule of thumb applies: stored in a pressure tank (air chamber), which also V 0.9–1 Q with bypass on-off control serves as a buffer to compensate pressure fluctuations. V 0.4 Q with idle control; In this way, brief consumption peaks are covered where without the operating pressure in the pipe fluctuating V = Chamber volume (m3) or dropping too severely. The air requirement when Q = Delivery quantity of the compressor (m3/min) the consumption peaks are present should not exceed the delivery quantities of the compressor for a lengthy Additional pressure tanks are often installed at the period of time. end of the piping system or before large-scale consum- The pressure in the tank is controlled by way of the ers, in order to compensate for high demand loads. fact that the compressor is switched off when a maxi- Correct dimensions for the piping system The following simple example shows how the load air consumption of 2,000 l/min (70.6 cfm) a continu- of compressor and pressure tank can be determined ous operating period of 1 minute is possible or with depending on the consumer: air consumption of 500 l/min (17.6 cfm) an operating Compressor: period of 4 minutes. Here, it must be borne in mind Delivery quantity 1,000 l/min (35.3 cfm) that many tools, especially screwdrivers, are only Pressure tank: switched on for short periods. For example, if an im- Volume 500 l (17.6 cf) pact wrench with an average air consumption of 20 l/s Switching cycle between 12 and 8 bar (42.4 cfm) is used four times a minute and works for At a final pressure of 12 bar, the compressor switches 3 seconds per screw connection (3 x 4 seconds pure off. Until the compressor is switched on again at 8 bar, working time in one minute), it actually only requires 12 bar – 8 bar = 4 bar and thus 500 x 4 = 2,000 l (70.6 cf) 20 x 3 x 4 = 240 l (8.5 cf) in this period. is available to consuming devices in this range, i.e. at
116 Pages | Valid until 06/2024 | Previous page | Next page
Choose your language
Legal issues
The manufacturer is exclusively responsible for the content, price and article details of the products and offers presented in the catalogues. Subject to technical and optical changes by the manufacturer and errors excepted.
Request form for special products
The ToolTeam® Procurement Service
Are you looking for products that are shown in the catalogue but cannot be purchased directly online?Our procurement service will be pleased to make you a non-binding and individual offer.