API 612 pdf download.Petroleum, Petrochemical and Natural Gas Industries—Steam Turbines—Special-purpose Applications
3 Terms and definitions
A guide to steam turbine nomenclature is found in Annex B. For the purposes of this Standard, the following definitions apply. 3.1 alarm point preset value of a measured parameter at which an alarm is actuated to warn of a condition that requires corrective action 3.2 anchor bolts bolts used to attach the mounting plate to the support structure or foundation 3.3 axially split split with the principal joint parallel to the shaft centreline 3.4 control mechanism all of the equipment between the speed governor and the governor controlled valve(s) (such as linkages, pilot valves, power servos, and so forth) 3.5 critical speed shaft rotational speed at which the rotor-bearing-support system is in a state of resonance 3.6 design equipment manufacturer’s description of various parameters relevant to the equipment NOTE This terminology should be used only by the equipment manufacturer and should not appear in the purchaser’s specifications. 3.7 fail safe system system which causes the equipment to revert to a permanently safe condition (shutdown and/or depressurized) in the event of a component failure or failure of the energy supply to the system 3.8 field changeable design feature that permits alteration of a function after the equipment has been installed NOTE The alteration may be accomplished by the following: a) soldering jumper leads to terminal pins especially provided for this purpose; b) employing circuit board mounted switches or potentiometers; c) using a shorting or diode pin type matrix board; d) using prewired shorting plugs; e) using authorized controlled access. 3.9 gauge board bracket or plate used to support and display gauges, switches, and other instruments NOTE A gauge board is open and not enclosed. 3.10 general-purpose turbines horizontal or vertical turbines used to drive equipment that is usually spared, is relatively small in size (power), or is in non-critical serviceNOTE General-purpose steam turbines are intended for applications where the inlet gauge pressure does not exceed 4 800 kPa (48 bar) (700 psi) and the inlet temperature does not exceed 400 ° C (750 ° F), and where the speed does not exceed 6 000 r/min. 3.11 governor controlled valve device that controls the flow of steam into or out of the turbine in response to the speed governor 3.12 hold-down bolts mounting bolts bolts that hold the equipment to the mounting plate or plates 3.13 hydrodynamic bearings bearings that use the principles of hydrodynamic lubrication NOTE The bearing surfaces are oriented so that relative motion forms an oil wedge, or wedges, to support the load without shaft-to-bearing contact. 3.14 local device (device) mounted on or near the equipment or console 3.15 maximum allowable speed highest speed at which the manufacturer’s design permits continuous operation 3.16 maximum allowable temperature maximum continuous temperature for which the manufacturer has designed the equipment (or any part to which the term is referred) when handling the specified fluid at the specified maximum operating pressure 3.17 maximum allowable working pressure maximum continuous pressure for which the manufacturer has designed the equipment (or any part to which the term is referred) when handling the specified fluid at the specified maximum operating temperature 3.18 maximum continuous speed highest speed at which the turbine, as built and tested, is capable of continuous operation, at any of the specified steam conditions 3.19 maximum exhaust casing pressure highest exhaust steam pressure that the purchaser requires the casing to contain on a continuous basis NOTE The turbine casing is subjected to the maximum temperature and pressure under these conditions.