Pneumatic Devices Research Articles

Pneumatic Control Systems for Biological Objects

General-purpose industrial pneumatics is shown to be a sound proposition for artificial blood circulation and respiration, perfusion, massage, suction, life support, conservation, etc. in medicine, cattle breeding, microbiology, and the food industry. The range of operating parameters of standard pneumatics tend toward negative pressure values (rarefaction), (such as USEEPA, TSIKL, VOLGA and other types of pneumatic sets manufactured in the USSR). The specifics of biological systems essential for the design of pneumatic control devices and the characteristic features of biological manipulators which differ from those of idustrial manipulators are discussed. A standard structure for biological systems is established.

Improvement in Accuracy of Pneumatic Delay

To reduce the probability distribution width of switching delay, it is necessary to use steep rise signals to the pneumatic devices. It is said conventional pneumatic delay of restrictor and capacitor combination causes ± 5 to 7 % errors, because signals rise slowly. To make the pneumatic delay accurate, the signals must rise steeply after the delayed time. A simple model for calculation shows one tenth reduction of error by using a soft flexible volume installed in a chamber. A new type inflating film capacitor was developed. The original film type can obtain ± 0.4 to 0.7 % errors, and a combination of film and pneumatic sensor gives ± 0.1 to 0.2 % in accuracy.

Some trends in the design and construction of steel penstocks at hydroelectric stations

1. Scientific-technical progress in the area of penstock construction should proceed in two directions: a) increasing the effectiveness of the designs of steel penstocks to provide a substantial increase of reliability and durability; b) creating a new mechanized technology for constructing penstocks with the use of modern pneumatic and hydraulic devices. 2. The technical and economic effectiveness of using high-strength steels in comparison with steels of ordinary quality and the usual low-alloy steels consists in the reduction of weight and increase in bearing capacity of the penstocks and their durability owing to less wear, increased strength, corrosion resistance, and cold strength. Along with a considerable saving of metal the labor intensity of manufacture and cost of the structures as a whole is decreased. The cost in this case decreases both as a result of the reduction in the consumption of steel and due to a decrease in the cost of transportation and assembly. 3. Of importance for penstocks embedded in rock in straight sections is the size of the rock-penstock space, which should be minimum, which will minimize the volume of rock excavation and concrete in this space.

Fluidics and pneumaticsprinciples and applications in anaesthesia

This article describes the construction and operation of fluidic and pneumatic devices in current use, as well as the principles of their use in medical devices. The designs for an automatic blood pressure cuff inflator, a blood pump and a high performance ventilator are presented.

De-icing of Radomes and Lock walls using Pneumatic Devices

AbstractA rough comparison between thermal and mechanical methods of de-icing indicates that mechanical methods could potentially de-ice with an order-of-magnitude less energy than that required to melt an ice accretion. Two applications of mechanical de-icing using pneumatically driven inflatable de-icers are described in this report. The first of these was the de-icing of a small cylindrical radome used for air navigational purposes. Two seasons of testing were conducted with a de-icer consisting of an inflatable-deflatable flexible plastic covering. The de-icer was driven by tanks with pressure and vacuum reservoirs that were recharged by an on-site air compressor in response to a pressure sensor. The de-icing cycle was activated by an ice detector so the system responded to icing events on a demand basis driven by the ice detector. The system proved successful in keeping the radome free of ice without manned operation and with small energy consumption in a mountain icing environment. The second application was an attempt to de-ice the walls of locks used in river navigational facilities. Ice usually formed at the high-water-mark by the freezing of the water exposed to low air temperatures or by the pressing of ice against the walls by ships using the locks. The de-icers consisted of air-driven hoses mounted on the wall covered by a thick flexible rubber mat and protected from ship damage by steel outer plates. This method was successful in removing ice accumulations up to 2 m long by 0.3 m thick over the area covered by the de-icer. Installation costs and the necessity for protection of the de-icer against abrasion by ships may make this de-icing method prohibitively expensive compared with methods which are not as susceptible to damage by ships (e.g. chemical coatings and electrical heating cables buried in the walls).

Transmission of a Continuous Square Wave down a Pneumatic Line

Using the electrical analogy, a solution for the transmission of a continuous square wave down a pneumatic line has been obtained. The results are compared with experiment and show good agreement.Using the theoretical results, it is possible to calculate the maximum separation between pneumatic (fluidic) devices that will still ensure satisfactory operation. Typically, it can be shown that at a frequency of 100 Hz, the output from a fluidic OR gate or bistable (see Appendix 1) may be transmitted 8 m and the amplitude of the signal will still be large enough at that point to switch a second OR gate or bistable.

Design of artificial pulmonary ventilation machine using pneumatic control devices

1. High-pressure pneumatic control systems are most suitable for simple, rate-controlled APV machines with active inspiration and passive expiration. 2. Low-pressure fluid and membrane control systems are more versatile, can be used in all ventilation machines, and consume little gas.

A NEW RANGE OF PNEUMATIC LUBRICATORS NOT DEPENDENT ON AIR VELOCITY

UNLIKE conventional air line lubricators, this new range of pneumatic devices does not depend on air velocity to distribute the oil; in fact oil distribution is independent of air flow, gravity, distance, pipe size or arrangement.

Ultrahigh Vacuum Bakeable Valves with Integral Spare Seal

The most desirable characteristics of an uhv valve are reviewed. The solutions which have been selected to obtain these characteristics are described; a special kind of sealing called “Induced Elasticity,” the use of pneumatic devices to compress the seal, and a simple way to actuate the closure device through the valve body without bellows. Finally, a short description is given of some of the valves which have been built in the laboratory, laying emphasis on the above features.

Theoretical and Experimental Aspects of the Production of Aerosols for Use in Atomic Absorption Spectroscopy

The role of the aerosol in atomic absorption spectroscopy is considered and theories of the production of aerosols by pneumatic and ultrasonic devices are outlined. The predicted droplet size is related to sensitivity and interference by Al and Si in the estimation of Mg. Experiments using pneumatic and ultrasonic (70-kHz and 115-kHz) nebulizers at sample flow rates from 0.05 ml/min to 3.5 ml/min and with spray chambers of 100-cm(3) to 500-cm(3) capacity are reported. The results obtained indicate that ultrasonic nebulizers must be operated at high frequency (>500 kHz) and high power to generate fine aerosols (~5-micro diam) at sample flow rates of 1-5 ml/min if they are to be an improvement in sensitivity and interference on the pneumatic nebulizer.

Pneumatics, Automata and the Vacuum in the Work of Giambattista Aleotti

In most of the more lively fields of physical enquiry in the first three decades of the seventeenth century, a striking contrast may be observed between the antiquity of the problems attacked, and the innovatory procedures applied to solve them. None of these questions, inherited from a past now remote, seemed more pressing than the time-honoured controversy of the plenum versus the vacuum, especially as the concept of the atomic structure of matter was so closely associated with the existence of the void. The more one studies the arguments produced at that time, the more one will be impressed with the value and importance, for the vacuists and the atomists, of the Pneumatics of Hero of Alexandria. When we read Galileo's explanation of combustion, “the extremely fine particles of fire, penetrating the narrow pores of the metal (too small to admit even the minutest particles of air or of many other fluids) would fill the minute intervening vacuum, and would set free these minute particles from the forced attraction which these same vacua exert’, we can hear clear echoes of Hero's account of disseminated micro-vacua. Now Hero's work is clearly divided into two sections: a theoretical preface and a collection of 78 “pneumatic devices”. One might be tempted to claim that he, rather than his fellow-atomist Lucretius, inspired the first tentative syntheses of seventeenth-century atomism but it would still be necessary to agree that his chief contributions to the achievements of that generation lie in the experimental techniques which they derived from his instrumentation. Were it not for the popularity of his pneumatic demonstrations, he could never have won such a great reputation as a natural philosopher. Without that reputation, his opinions on this topic would not have been valued as almost equal to those of the mighty Aristotle, especially since he was so decidedly in the minority.

Measuring the wear of face surfaces in pneumatic devices

Measuring the wear of face surfaces in pneumatic devices

Static Conductor Devices for Railroad Use with Particular Emphasis on Rapid-Transit Cars

Railroads, along with most other industries, have found in recent years an ever-increasing number of applications where static components can replace the long-standing electromagnetic, pneumatic and mechanical devices. This paper discusses briefly a few such applications, pointing out some features which static components can offer as compared with conventional devices. Details concerning a new static notching system used in type SCM (simplified cam magnetic) control for rapid-transit car propulsion emphasizes recently developed advantages to be obtained with static components.

Cleaning Action of Cotton Card Equipped with Metallic Card Clothing

Fewer nep slivers are obtained from a card equipped with metallic card clothing than from a card equipped with the conventional wire fillet clothing. A combination of metallic card clothing with a larger tooth angle on the cylinder and metallic card clothing with a smaller tooth angle on the doffer reduces neps and impurities in the sliver. These facts are related to the fiber density on the cylinder surface. We considered this relation and the cleaning action in the lickerin part, and made sure that increases in the speeds of all parts of a card equipped with metallic card clothing would increase production and improve sliver quality. Then we designed and built a new card which had various features, including smaller diameters and higher speeds of the lickerin roll, the cylinder, and the doffer, and the use of pneumatic devices and stationary flats. Spinning tests proved that production could be raised fivefold with no lowering of the quality of the sliver or yarn, and that wastes, the floor space and labor could be reduced considerably.

Electrical Control Features of the Avon Supercritical-Pressure Unit

The trend toward increased electrification inside the modern power plant is evidenced by the Avon supercritical-pressure unit. The application of electrical controls to economically and reliably accomplish equipment protection and interlocking functions directly, or in combination with hydraulic and pneumatic control devices, has been demonstrated on commercial subcritical pressure units. They will continue to do so on the supercritical-pressure units. 1. Basically, the over-all trip protection for the supercritical-pressure turbine and steam generator is not radically different from that for large subcritical units, except for several important additions. 2. Automatic transfer of selected auxiliary motors to the start-up source becomes more important. 3. The monotube once-through steam generator requires a large number of hydraulic and remotely operated electrical controls. 4. Automatic starting of boiler feed pump prime movers and other auxiliaries may increase the over-all reliability of the main unit while adding little complexity to the control system which is designed for complete remote operation. 5. The complexity and number of electrica controls required on main control room panels for a supercritical unit far exceeds those required for a large conventional highpressure high-temperature unit.

Closure to “Discussions of ‘Sine-Wave Generators: A Survey of Pneumatic, Mechanical, and Electrical Devices for Obtaining Frequency-Response Data’” (1954, Trans. ASME, 76, pp. 1183–1184)

Closure to “Discussions of ‘Sine-Wave Generators: A Survey of Pneumatic, Mechanical, and Electrical Devices for Obtaining Frequency-Response Data’” (1954, Trans. ASME, 76, pp. 1183–1184)

Sine-Wave Generators: A Survey of Pneumatic, Mechanical, and Electrical Devices for Obtaining Frequency-Response Data

Abstract Data are given on pneumatic, mechanical, and electrical sine-wave generators which are or can be used to impose the “wiggle” necessary for the taking of frequency-response data in the industrial-control field. The high points are covered from a functional rather than a theoretical viewpoint and a reference list is presented to assist those interested in additional information.

Private Nuclear Research

Heralded as the “first privately-financed laboratory dedicated to research in nuclear power”, the newly created Walter Kidde Nuclear Laboratories, Inc. has announced that it will perform research, development, and experimentation in the field of nuclear energy with services to be available to other organizations interested in the design of nuclear power plants or in applications of nuclear technology to their products and processes. A subsidiary of Walter Kidde & Company, Inc., manufacturers of fire protection systems and pneumatic devices for aircraft and marine application, the new organization was established in mid-April and expects to begin construction shortly of laboratory research facilities on Long Island.

Latest Developments in Aircraft Controls and Instrumentation

Abstract As the complications of operation on modern aircraft have increased, the provision of automatic controls has become a necessity to relieve the pilot and other operating personnel of the strain of continual manual control throughout flight periods. Electrical, pneumatic and hydraulic devices have been developed to accomplish reduction in manual functions but these must be controlled automatically by sensing elements which react to conditions encountered. Details of a basic control system having many and varied applications are cited in this paper.