Actuating device

Pie2oelectric materials are used in many different types of sensing—actuating devices. A few appHcations include printing, monitoring of performance behavior of adhesive joints, and intelligent processing. 

Float-Actuated Devices Float-actuated devices are characterized by a buoyant member that floats at the interface between two fluids. Since a significant force is usually required to move the indicating mechanism, float-actuated devices are generally limited to liqiiid-gas interfaces. By properly weighting the float, they can be used to measure hquid-liquid interfaces. Float-actuated devices may be classified on the basis of the method used to couple the float motion to the indicating system as discussed below. 

Data on spare and parallel equipment are often omitted. Valving is also generally omitted. A alve is shown only where its specification can aid in understanding intermittent or alternate flows. Instrumentation is indicated to show the location of variables being controlled and the location of the actuating device, usually a control valve. To help the reader better understand the process flow sheet, a list of commonly used symbols is presented in Fig. 5.9.1. 

The energy within a hydraulic system is of no value until it is converted into work. Typically, this is accomplished by using an actuating device of some type. This actuating device may be a cylinder, which converts the hydraulic energy into linear mechanical force a hydraulic motor, that converts energy into rotational force or a variety of other actuators designed to provide specific work functions. 

The fluid provides the vehicle that transmits input power, such as from a hydraulic pump to the actuator device or devices that perform work. 

One of the outstanding features of fluid power systems is that force, generated by the power supply, controlled and directed by suitable valving, and transported by lines, can be converted with ease to almost any kind of mechanical motion. Either linear or rotary motion can be obtained by using a suitable actuating device. 

An actuator is a device that converts fluid power into mechanical force and motion. Cylinders, hydraulic motors, and turbines are the most common types of actuating devices used in fluid power systems. This chapter describes various types of actuating devices and their applications. 

Anon, Propellant Actuated Devices , AMCP 706-270, Engineering Design Handbook, US Army Materiel Command, 5001 Eisenhower Ave, Alexandria, Va 22333 (Sept 1975)... 

No-Fire Level. The max level of electric energy input that will in no case, within a specified time, initiate an expl-actuated device Ref K.O. Brauer, Handbook of Pyrotechnics , Chemical Publishing Co, NY (1974), 387... 

Temperature Percussion Primers , Propellant-Actuated Devices Symposium, FrankfordArs (June 1961) 10) Anon, Detonator Output... 

A special category of ignition system is the cartridge actuated device (CAD) also known as the Propellant Actuated Device (PAD) which serves to generate the mechanical force to close switches (in the manner of a squib) or to perform otherwise mechanical work (Vol 2, C70-R Ref 138, p 167)... 

Local automatic—some isolation valves may be automatic, but locally actuated. In this case, the actuation device may be a fusible-link or fusible-tubing arrangement. 

Thermostats—bimetallic strip, snap-action disk, and thermostatic cable Continuous discrete conductors Thermistor sensors Rate of temperature rise Copper tubing heat-actuated devices (HADs) Thermoelectric Combined rate of rise/fixed temperature Rate compensation Oil mist ... 

At least one remote manual actuation device independent of the manual actuation device located at the system actuation valve should be installed for all automatic water spray systems. 

Control valves, including all automatic and manual-actuating devices, should be tested at regular intervals. 

Dry powder inhalers are generally described as breath actuated devices, because the inspiratory airstream releases the dose from the dose system and supplies the energy for the generation of fine drug particles from the powder formulation. Because the efficiency of dose release and powder disintegration increases with increasing inspiratory flow rate for most DPIs, these devices would be better described as breath controlled devices. In Section 3.9, the effect of resistance and clinical conditions on the flow curve and relevant flow parameters for DPIs are discussed. 

Prior to WWII. Cartridge-Actuated Devices (CAD s) or Propellant Actuated Devices. The... 

Exactor. A "cartridge-actuated device" (See Vol 2 of Encycl, p C71) intended to release die safety mechanism of another cartridge-actuated device. The exactor operates by gas pressure supplied from the initiator"... 

Expansion Ratio. In jet propulsion it is the ratio of die nozzle exit section area ro the nozzle throat area. In cartridge actuated device, it is the ratio of final to initial volume in a stroking type of CAD Ref Glossary of Ord (1959), 109-R... 

They are known as CADs (cartridge-actuated devices) (Ref 2)... 

Encycl PATR 2700, Vol 2 (1962), pp C70-R to C72-R [Cartridges and Cartridge-Actuated Devices (CADs), called Propellant Actuated Devices] 3) Encycl, PATR 270Q Vol 2 (1962), p C91-R [Catapult (Modern)]... 

Explosive Starter. A device, used to start diesel engines consists of a cartridge-actuated device 1 (CAD), inserted in the head oi one of the cylinders. On detonation of cartridge a shock (kick)is produced which pushes the piston down and starts the whole engine Note CAD s ate described m Vol 2 of Encycl pp C70-R to C72-R... 

The microprocessor-based systems should be programmed, challenged, and validated to eliminate the exposure of one product to another through control failure. Valves and actuation devices used to divert product flows should be programmed properly and validated for their adequate functionality. 

H.A.D.(Heat Actuating Devices) Thermostatically controlled devices used to activate fire equipment, alarms, or appliances. 

Some of the items already described in this Encyclopedia, may also be called "special devices , as for example, "Cartridge-Actuated Devices (See Vol 2, pp C70-L to C72-R... 

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