Universal System of Elements for Industrial Pneumatic Automation
Universal System of Elements for Industrial Pneumatic Automation (USEPPA)
also, Standard-module Pneumatic Instrumentation System (SMPIS); in the USSR, a system of self-contained, standardized pneumatic components used in constructing pneumatic automatic control units and systems.
USEPPA was developed in the USSR in 1960 and 1961. Each element of the system is designed to execute a specific elementary operation, such as amplification, repeating, comparison, or storage. Several identical components can be used either in a single device or in several devices. Various combinations of USEPPA elements are used to construct regulators; automatic optimization systems; relay devices for starting, stopping, protection and blocking; cyclic automation systems; and remote control devices. USEPPA components are simple in design, adaptable to streamlined manufacture, relatively compact, and equipped with standardized fittings. Pneumatic automatic control devices are assembled from USEPPA components and installed on mounting boards; all connections are made through pneumatic channels provided inside the mounting boards. The functional capabilities of the USEPPA system permit continuous discrete and combined operations.
Continuous (analogue) operations are accomplished by comparison elements (amplifiers) with two or four inputs, various types of repeaters, nonadjustable and variable pneumatic capacitances, and adjustable and nonadjustable pneumatic resistances. Such components are used in constructing pneumatic computing amplifiers, as well as time-lag elements on which pneumatic analogue equipment is based. Components used to build discrete (relay) pneumatic devices include universal pneumatic relays and dual check valves; they perform elementary logic operations. Time operations in relay circuits are realized by means of natural delays (in time-lag elements) or forced delays provided by discrete pneumatic signals. Combined (continuous-discrete) operations are provided by pneumatic valves, elements that store continuous signals, and linear pulsating resistances. Such components operate with both continuous and discrete signals and thus substantially widen the possibilities for constructing pneumoautomatic devices. Components in the USEPPA system also include various auxiliary devices, such as setters, pneumatic push buttons, pneumatic tumblers, and pneumatic-electric and electric-pneumatic converters.
The use of USEPPA components widens the functional capabilities and improves the technological and economic indexes of pneumoautomatic devices. The efficiency of the system’s use can be improved through mass production of various complex standardized modules and units, rather than individual components. Such standardized modules and units may be combined into assemblies.
A system of pneumoautomatic devices based on USEPPA components was introduced in the USSR during the 1960’s under the designation “Start.” The system is suitable primarily for the construction of branched regulator operation and optimization systems for continuous production processes. The Tsentr system, introduced in the early 1970’s, is designed for automatic control systems for continuous production processes; it consists of a unitized complex of functional pneumatic devices. Tsentr components are large functional blocks assembled from USEPPA components.
The Tsikl system was designed in the early 1970’s. It consists of unitized subassembly blocks designed for discrete control of cyclic and periodic processes. The system uses modernized components of the USEPPA system, including components with elastic and movable parts and flow (jet) components. All modules and devices are mounted in standardized containers, cabinets, consoles, and the like.
The USEPPA and Start systems were awarded the Lenin Prize in 1964, and the Tsentr system was awarded the State Prize of the USSR in 1974.
REFERENCESBerends, T. K. [et al.]. “Elementnyi printsip v pnevmoavtomatike.” Priborostroenie, 1963, no. 11.
Berends, T. K., T. K. Efremova, and A. A. Tagaevskaia. Elementy i skhemy pnevmoavtomatiki. Moscow, 1968.
T. K. BERENDS