Pneumatic logic

Grover WH, Jensen EC, Lvester RHC, Mathies RA (2006) Programmable pneumatic logical circuits for microfluidic device control. In Proceedings 10th international conference on miniaturized systems for chemistry and life sciences (pTAS 06), Tokyo, Japan, 5-9 November 2006, pp 506-508... 

Rhee M, Bums MA (2009) Microfluidic pneumatic logic circuits and digital pneumatic microprocessors for integrated microfluidic systems. Lab Chip 9 3131-3143... 

For pneumatic transmission systems, the signal range used for the transmission is 3 to 15 psig. In each pneumatic transmission system, there can be only one transmitter, but there can be any number of receivers. When most measurement devices were pneumatic, pneumatic transmission was the logical choice. However, with the displacement of pneumatic measurement devices by electronic devices, pneumatic transmission is becoming less common but is unlikely to totally disappear. 

As mentioned earlier, pneumatic and hydraulic systems have been extensively used in hazardous environments to provide the power necessary to move and drive machinery to complete needed tasks. Their use has demanded development of complex logic systems which involve the addition of valves and piping. These logic control systems are often hard to design, debug, construct, and maintain. 

A fluid bed granulation process can be controlled by pneumatic analog control devices or by using state-of-the-art prograimnable logic controllers (PLCs) or com-... 

Interlock and sequential control logic is performed by mechanical/electric relays and timers and the production train shutdown is performed by a combination of mechanical/electric relays and pneumatic relays. 

Logical elements (pneumatic switching elements) as links for connective instructions... 

Materials-handling equipment is logically divided into continuous and batch types, and into classes for the handling of liquids, solids, and gases. Liquids and gases are handled by means of pumps and blowers in pipes, flumes, and ducts and in containers such as drums, cylinders, and tank cars. Solids may be handled by conveyors, bucket elevators, chutes, lift trucks, and pneumatic systems. The selection of materials-handling equipment depends upon the cost and the work to be done. Factors that must be considered in selecting such equipment include ... 

Fig. 15 Eight-bit digital pneumatic microprocessor based on pneumatic Boolean logic circuit [55]. Reprinted with kind permission from [55] Copyright 2009 Royal Society of Chemistry...

Since 1970 considerable changes have taken place in the means by which processes are controlled. Pneumatic controllers and relay logic have been replaced by solid-state logic and more recently by programmable logic controllers. During the same time the cost of the hardware has fallen and the availability of appropriate software has increased while other process costs have risen. The inclusion of such equipment has therefore become more easily justifiable. 

The study of the atmosphere led to the discovery of nitrogen. Although it is associated with the name of a certain scientist and a certain date, this certainty is misleading. It is rather difficult to separate the history of nitrogen discovery from the mainstream of pneumatic chemistry one can only think of a more or less logical sequence of events. 

The fundamental principle behind a computerised sewing machine is the synchroniser, a device that monitors and counts the rotation of a hand wheel. While the synchroniser acts as the logic provider to the electronic circuit, the solenoids or pneumatic cylinders move the machine parts. With one complete rotation of the hand wheel, the needle bar completes one cycle of needle up/down movement. For example, when the needle is at topmost position, and the electronic marker is set at 90° position on the hand wheel, every time the electronic marker come to 90° position on the hand wheel the needle will be at topmost position. Using this logic, the synchroniser can... 

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