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300 Fill-in-the-Blank Questions: 1. A pump is a machine that converts the (mechanical) energy of a prime mover into the ( ) and kinetic energy of the fluid being transported. 2. A motor is mainly composed of ( ) and ( ). 3. The lowest temperature at which a combustible material can ignite on its own is called ( ). 4. The water contained in the oil within the tank, when vaporized by heat, sees its volume increase rapidly to more than ( ) times the original value; it rises swiftly to the oil surface, leading to bumping. 5. The stroke count of the steam reciprocating pump should be less than ( ) times per minute. 6. 1 engineering atmospheric pressure is equal to ( ) meters of water column, and it is also equal to ( ) millimeters of mercury column. 7. For a substance to burn, three conditions must be met simultaneously, which are ( ), ( ), ( ). 8. All types of operation records and shift handover logs must be carefully written in ( ) style. 9. A low-pressure vessel refers to a vessel whose design pressure P is between 0.1 and ( ) MPa. 10. In petroleum measurement, the standard density of petroleum is represented by ( ). 11. Common temperature scales include Celsius, ( ), and ( ). 12. When working on the tank, one should stand in ( ), to prevent ( ). 13. To thaw a frozen oil tank heater, ( ) can be sent into the tank to melt it. 14. Frozen valves and pumps can be thawed using ( ) or ( ); forced use is not permitted. 15. The production area for flammable liquids with a flash point higher than the ambient temperature is called ( ). 16. There are two reasons why the drain valve does not discharge water: one is ( ) ； The second is ( ). 17. During the shutdown and inspection period of the storage tank, as cleaning begins, the oxygen content must be greater than ( ). 18. The measurement of oil entering and leaving the plant ( ) is intended to determine the ( ) of the oil at such times, which serves as a basis for settlement. 19. A steel pipe has an inner diameter of 100 mm and a wall thickness of 4 mm. What is the model number of this steel pipe? ( ) 20. Pipeline laying can be categorized into three methods: overhead, ( ), and ( ). 21. When a centrifugal pump is in operation, pressure differences on both sides of the impeller cause ( ). 22. Heat always automatically transfers from an object at a ( ) temperature to an object at a ( ) temperature. 23. Among the locomotive whistles, one long sound indicates that the locomotive is ( ); two long sounds indicate that the locomotive is ( ); one short sound indicates that the locomotive is responding to a ( ) signal. 24. Low voltage refers to a voltage relative to ground that is below ( ). 25. The ( ) flowing through any cross-section of a pipe within a unit ( ) is called flow rate. 26. When checking the level gauge of an oil tank, one must ensure that ( ), ( ), and the reading is accurate. 27. When starting a centrifugal pump, one should first ( ), then start the electric pump; once the outlet pressure reaches the specified value, ( ) should be done, and after the outlet pressure stabilizes, finally ( ). 28. The relative error of the instrument = ( ). 29. If the temperature of the liquid drawn in by a centrifugal pump is too high, it will cause ( ) phenomenon. 30. As the temperature rises, the volume of the oil increases ( ), while its density decreases ( ), and its relative density also decreases ( ). 31. The pipeline with a nominal diameter of DN100 is ( ) inches. 32. To eliminate axial thrust, multi-stage centrifugal pumps employ a ( ) device. 33. At a certain temperature, the ratio of the ( ) of an oil to the mass of pure water in the same volume is called the relative density of that oil. 34. During the measurement process, both the F value and K value should be rounded to the ( )th decimal place. 35. When the current of the centrifugal pump is too high, slowly control the ( ) valve of the pump until the current is within the rated value. 36. Switching to handle empty cans can easily lead to ( ) phenomena. 37. Switching production tanks can easily lead to ( ) phenomena. 38. The five principles of equipment lubrication management are: fixed location, fixed timing, ( ), ( ), and fixed person in charge. 39. The quality policy is the organization’s overall quality purpose and ( ) officially issued by the organization’s ( ). 40. The filter screens used for various lubricants in Y-type centrifugal pumps are made of steel mesh with ( ) mesh size. 41. According to the direction of fluid flow, globe valves can be divided into ( ), ( ), and angle types. 42. The requirements regarding the five conditions under which refined oil shall not leave the factory are ( ), and it shall not be released if the packaging containers are not up to standard ； In special cases, the production supervisor must sign before the goods can leave the factory ； The product will not leave the factory without a sample being kept. 43. The lowest temperature at which lubricating oil can be pumped using an oil pump is called ( ). 44. During the normal operation of a safety valve, the valve between the safety valve and the container must be ( ), and secured with something to prevent it from being turned by anyone. 45. Strictly control the oil receiving temperature; under normal circumstances, when the oil temperature exceeds ( )°C, it is strictly prohibited to use steam for line cleaning. 46. The vertical distance from the liquid surface to ( ) is called the verification ruler. 47. When the pipeline is filled with oil and equipped with a heat tracing system, it must be handled in accordance with the regulations ( ). 48. The transport temperature of oils with high freezing points should be above ( )℃ of their ( ). 49. Those who do not wear appropriate clothing are strictly prohibited from entering ( ) and ( ). 50. For temperature measurement in oil tanks, the measurement point should be taken at the liquid level ( ), and the temperature sensor box should remain in the oil for ( ) minutes. 51. Our company’s quality policy is ( ) + ( ) + ( ) = high-quality Kunlun products. 52. In HVI200, HVI refers to ( ). 53. The fire watcher should be familiar with the production process flow and know how to use ( ). 54. Viscosity is a measure of the ( ) that arises between molecules when a liquid flows, due to ( ). Common methods for expressing the viscosity of oils include: ( ), ( ), ( ) etc. 55. The indicators for evaluating the viscosity-temperature properties of oils are ( ) and ( ). 56. The functions of transformer oil inside a transformer are ( ) and ( ). 57. The viscosity of lubricating oil is related to the structure of hydrocarbons: when several hydrocarbons have the same number of carbon atoms, ( ) has the lowest viscosity, ( ) has a higher viscosity, and ( ) has the highest viscosity. 58. Cycloaliphatic hydrocarbons are the ( ) carriers of lubricants, while n-alkyl side chains are the ( ) carriers of lubricants. Taking into account both the viscosity and visco-temperature properties of lubricating oil, ( ) is the ideal component for lubricating oil. Although normal alkanes have good viscosity-temperature properties, their ( ) is very poor; therefore, they are not an ideal component for lubricants. 59. The viscosity-temperature properties of oils are related to the molecular size and structure of hydrocarbons. Among the hydrocarbons in lubricating oils, those with ( ) have the best viscosity-temperature properties; the viscosity index increases as the molecular weight increases. When the number of carbon atoms is the same, isomerized alkanes have a higher viscosity index than n-alkanes. The higher the number of rings in naphthenes (), the better their viscosity-temperature properties. 60. The efficiency of a centrifugal pump is not 100% because there are energy losses during its operation, and these energy losses include ( ), ( ) and ( ). The higher the viscosity of the fluid pumped, the greater the energy loss. As a result, the pump’s head and flow rate ( ), efficiency ( ), and power ( ) all decrease. 61. The 100YⅡ‑120×2A type centrifugal pump: the meaning of its code is as follows – 100 represents ( ), Y denotes ( ), II indicates ( ), 120 signifies ( ), 2 means ( ), and A stands for ( ). 62. Equipment lubrication comes in two forms: ( ) and ( ). 63. Before adding blending additives to oil products, it is necessary to ( ), ( ), and ( ). 64. LZ5957 should not be added to anti-wear hydraulic oil, as it can react with the additives ( ), causing the color of the oil to change ( ). 65. The addition of antifoam agents to lubricants does not prevent the lubricant’s tendency to ( ), but rather it reduces the duration for which foam exists. 66. During the formulation of internal combustion engine oil, （ ） is an important indicator used to control the amount of additives added. 67. When blending oils containing antifreeze agents, it should be added （ ）。 68. The heating methods for oil tanks are ( ) and ( ). 69. When blending additives with base oil, it is essential to avoid thick-phase contact between ( ). 70. During the lubricant processing, the viscosity of the lubricant fractions decreases after dewaxing, and it decreases further after refining. 71. The oil dipstick consists of three parts: ( ), ( ), and ( ). 72. When formulating anti-ammonia turbine oil, the greatest concern is the contamination of T202 additive, which can cause the ( ) parameters of the oil to fail to meet the requirements; therefore, the formulation system must be kept clean. 73. When formulating two-stroke gasoline engine oil, ( ) is added to ensure the miscibility of the product. 74. The role of low-molecular-weight polyisobutylene in formulating two-stroke gasoline engine oil is ( ). 75. In the formulation of anti-ammonia turbine oils, T705 can improve the oil’s resistance to ammonia and its rust-preventing properties, but it affects the oil’s （ ） performance. 76. In the formulation of anti-wear hydraulic oil, in order to reduce the impact of （ ） on the air release properties of the oil, it is necessary to strictly control its amount added. 77. The sulfur content in thioethene is required to be no less than 40%, and this level of sulfur content has an impact on the （ ） of 85W/90GL vehicle oils. 78. The function of antioxidants or antioxidant-anticorrosive agents is to inhibit the （ ） process of lubricating oils, to deactivate the （ ） effect of metals, and to delay the （ ） of the oil. This extends the service life of the oil products while protecting the metal surface from acid corrosion. 79. The flow rate indicated on the nameplate of a pump refers to the flow rate when the pump’s efficiency is ( ). 80. The mechanical impurities and moisture in lubricating oil refer to the （ ） percentage of impurities and moisture contained in the lubricating oil. 81. The electrical performance indicators of transformer oil mainly include ( ) and ( ). 82. The three forms of heat transfer are ( ), ( ) and ( ). 83. Appropriately increasing the degree of oil refining is beneficial for improving the quality of oil, but excessive refinement can affect the oil’s （ ）、（ ）and（ ）。 84. The flow states of liquids are divided into ( ), ( ) and ( ) three types. 85. The temperature of the rolling bearings in a centrifugal pump must not exceed （ ） ； The motor temperature must not exceed ( ). 86. During the oil receiving process, when it is necessary to transfer the tank, the operation principles of （ ） must be strictly followed. 87. The opening pressure of the safety valve must not exceed ( ) of the container’s pressure; generally, it is adjusted by adding ( ) to the operating pressure of the equipment. 88. In containers that hold high-temperature, highly corrosive, or condensable media, a （ ） device should be installed between the pressure gauge and the container. 89. The allowable voltage fluctuation for ordinary motors is within （ ） of the rated voltage. 90. Oil products are subject to （ ）inventory taking and measurement, mainly in order to （ ), so as to check the implementation of the operational procedures at that stage. 91. Oil tanks must be equipped with lightning protection and anti-static devices, and the grounding resistance for lightning protection should not exceed（ ） ； The anti-static resistance should not be greater than ( ). 92. For newly built, overhauled, and reinstalled tanks, calibration can only be carried out after filling them to 100% of their capacity and waiting for ( ) hours. 93. Safety inspections are effective measures for identifying and eliminating potential accident hazards in a timely manner. Depending on the specific circumstances, they can be broadly classified into ( ), ( ) and ( ). 94. The fundamental core of Total Quality Management is to emphasize the improvement of ( ), ensuring and enhancing ( ), so as to achieve a comprehensive improvement in the ( ) of enterprises and society. 95. The minimum turning radius specified for railways is ( ) meters, and this value can be increased to ( ) meters for enterprise-specific lines. 96. Combustible liquids with a flash point lower than ( ) are referred to as flammable liquids. 97. For canned oils, in order to reduce oil loss, it is necessary to minimize ( ). 98. The capacity of one oil tank per meter is 500 cubic meters. If 25 cubic meters of oil are added per hour, then after 24 hours, the oil level in the tank will rise by ( ) meters. 99. Corrosion refers to the damage caused by oils to materials, and it usually relates to the presence of ( ) in the oils. 100. When Class A and B flammable liquids enter storage tanks and tank trucks, the initial flow velocity should not exceed ( ). 101. When pressure and temperature are constant, the ( ) of the fluid is also constant. 102. In the SI unit system, the unit of density is ( ). 103. The mass of a fluid per unit volume is called the ( ) of the fluid. 104. In the SI unit system, the unit of pressure is ( ). 105. When shutting down a centrifugal pump, one should first ( ). 106. In the antifoaming system, antifoam agents are either insoluble or have very low solubility, but they still possess certain ( ) properties. 107. The foaming phenomenon of lubricating oil is generally expressed by the foaming power and the ( ) of the foam. 108. A hydraulic press is made using the principle of ( ). 109. The ( ) applied to a confined liquid enables the liquid to be transmitted in all directions at its original volume. 110. The shear stress generated by viscosity is proportional to the velocity gradient ( ). 111. To prevent static electricity from forming in oil products, during their transportation ( ). 112. When gas flows through pipelines, the flow velocity should generally be kept within the range of ( ) m/s. 113. When draining water from an oil tank and the drainage valves are connected in series, what should be done at the end of the drainage process? 114. When pressure changes, the viscosity of a liquid increases as pressure rises ( ). 115. The heat required to raise the temperature of 1 kilogram of a substance by ( )°C is called the specific heat of that substance. 116. The diameter of the delivery pipeline is calculated based on ( ). 117. When liquid flows in pipelines, the flow velocity should generally be kept within the range of ( ) m/s. 118. The head losses associated with fluid flow through pipes are mainly caused by: the roughness of the inner surface of the pipe, the diameter and length of the pipe, the flow velocity and flow regime of the fluid, as well as ( ). 119. In a computer, the Chinese meaning of CPU is ( ). 120. Under medium load and speed conditions, the temperature of the friction surface can rise to ( )°C, causing the oiling agents to lose their adsorption capacity and resulting in desorption. 121. By mixing fuller’s earth with lubricating oil at a relatively high temperature, gums, asphaltenes, and residual solvents in the oil are adsorbed. This alters the ( ) of the oil, reduces its ( ), and improves its stability. 122. An important indicator for judging the adsorption capacity of kaolin for polar compounds is ( ). 123. The most effective, and most common, antifoaming method is ( ). 124. Barium and sodium petroleum sulfonates are by-products of the production of ( ) oil. 125. Barium sulfate, which is produced by neutralization methods and is primarily used as an anti-rust agent and detergent-dispersant in internal combustion engine oils, is （ ） in nature. 126. Adding a ( ) agent is aimed at solving the problem where many fuel additives disperse water into the fuel, resulting in a cloudy, foggy fuel mixture. 127. In PN16 on a valve, PN stands for ( ). 128. The additive most commonly used in petroleum products is ( ). 129. In the development of lubricants, the application of ( ) plays a decisive role. 130. A leaky inlet pipeline of the steam pump will result in a decrease in the pump’s displacement ( ). 131. When the unit is put into operation, the pipes must be free of any accumulated water to prevent the occurrence of ( ) when in contact with hot oil. 132. Additives used for the purpose of reducing friction and wear are called ( ) agents. 133. The state in which there is neither evaporation of liquid nor condensation of vapor on a macroscopic level is called ( ) state. 134. The lower the relative density of a liquid, the lower its cohesion, and the faster its evaporation rate ( ). 135. The mass transfer of gases between various parts of a system caused by non-uniform temperature distribution is called ( ). 136. The ( ) of any substance is a function of temperature. 137. The losses that occur when oil is stored statically in oil tanks are mainly ( ) losses. 138. The three special features of military oil are ( ), ( ), and ( ). 139. In the formulation of internal combustion engine oils, the main functions of adding detergents and dispersants are: ( ), ( ), ( ) and ( ). 140. The ( ) of petroleum products produced from paraffinic crude oils containing a high proportion of n-alkanes is higher. 141. Industrial lubricants are classified based on their dynamic viscosity at ( )°C. 142. The lubricant for various gears, worms, and other such devices is ( ) oil. 143. The lubricating oil used to lubricate machine tools and various machinery is ( ) oil. 144. The effect of lubricant in flushing away the metal debris that is worn off the friction surface is called the ( ) effect. 145. When it is necessary to replace the oil in the pipeline, the amount of replacement should be no less than ( ) times the amount of oil present in the pipeline. 146. The effect of lubricant in cushioning machine components and reducing mechanical vibrations is called the ( ) effect. 147. Viscosity is an indicator for evaluating the ( ) of oils, that is, the ( ) of oils. 148. The viscosity grade of gasoline engine oil is selected primarily based on the ( ) of the engine being used. 149. The viscosity value of L-HL 68 at 40°C is ( ). 150. The main basis for processing lubricant components is ( ). 151. The level of the aniline point indicates ( ). 152. When heating and stirring oil that contains excessive water, the purpose of opening the light-transmitting holes and the sight-glass ports on the top of the tank is ( ). 153. Residue and acid value reflect the ( ) of lubricating oil; the higher the residue, the higher the acid value, indicating a greater degree of refining. 154. When the pipe diameter remains constant, the flow velocity of the medium in the pipeline is proportional to the flow rate ( ). 155. The function of refining clay is to improve the ( ) of oil products, reduce ( ), and enhance ( ) as well as corrosion resistance. 156. The lowest temperature at which an oil product can still flow when cooled under specified conditions is called ( ). 157. The main reason for the unqualified transparency of lubricating oil is ( ). 158. After oxidation, the inherent characteristics of lubricating oil are acid value ( ), and residue carbon ( ). 159. Due to a leak in the heating tube of the oil tank, high temperatures can cause the lubricating oil to fail the ( ) test. 160. In the centrifugal pump 150YI-67×6, the number 67 represents ( ). 161. The design pressure of a pressure vessel is determined by the operating pressure and the pressure setting of the safety valve; what is the relationship between these three elements? 162. If the performance of the demulsifier declines and its effectiveness decreases, it will cause the ( ) of the lubricating oil to be substandard. 163. Oil is primarily composed of two elements, which account for approximately ( ) of the total amount of elements. 164. From the principle of economic efficiency, ( ) should be reflected in the pump house process. 165. From the perspective of flexible operation and quality assurance, ( ) should be reflected in the pump house process. 166. Alkenyl succinic acid is ( ), with the code name ( ). 167. There are two methods to lower the freezing point of waxy oils, namely ( ) and ( ). 168. T202 is a ( ) agent, added to lubricants to prevent their oxidation and corrosion. 169. The greater the heat transfer coefficient, the ( ) the thermal load of the heat exchanger. 170. Among the main physicochemical property indicators of the T803 antifreeze, the flash point by the open cup method shall be no less than ( )°C. 171. The amount of antifreeze used varies depending on the hydrocarbon composition, viscosity, and wax content of the oil, and is generally ( )%. 172. The “three skills” required for using equipment are the skill of ( ), the skill of ( ), and the skill of ( ). 173. The heating temperature of the T-501 additive must not exceed ( )°C. 174. If there is a large difference between the flash point of the lubricating oil and the specified value, the type of oil can be changed or ( ). 175. Parallel testing refers to two or more measurement processes carried out on the same sample, in the same laboratory, using ( ) instruments and ( ) operators, following the steps specified in the testing method. 176. The static grounding wire is a device used to prevent ( ) and eliminate ( ). 177. If the ash content of the lubricating oil is not up to standard but is close to the acceptable level, a ( ) test can be conducted. 178. When the flow rate is constant, the velocity of the oil flowing in a pipeline with a larger diameter is ( ). 179. The function of a steam trap is ( ), to reduce ( ). 180. 85W/90 GL-5 belongs to ( ) in terms of its application. 181. The storage temperature for antioxidant and anti-corrosion agents should not exceed ( )°C. 182. The categories of clean dispersants are mainly classified based on the ( ) in the matrix. 183. The commercial indicator for evaluating industrial products of a specific type of cleaning dispersant is ( ). 184. The effect of lubricant in removing the concentrated load at the contact points is called the ( ) effect. 185. The grade of lubricant products is indicated by the ( ) value of kinematic viscosity. 186. The ( ) of equipment is an important aspect of equipment management. 187. For pipelines that do not require welding after shutdown, after the medium is removed from the system, it should be ( ). 188. Flammable pipelines that have been inspected, modified, and repaired must be ( ) before use. 189. The method of cleaning an oil product depends on the （ ） of that oil product. 190. The filter in front of the pump should be cleaned ( ) once. 191. When cleaning pipelines, the pressure of the cleaning medium must be ( ) higher than the pressure of the oil in the pipeline. 192. The packing of a tank root valve can only be replaced when ( ). 193. When two centrifugal pumps of the same model are used in series, their head is ( ) the sum of their heads when used individually. 194. The purpose of adding an insulation layer to pipelines is ( ). 195. In principle, the general direction of line sweeping should be consistent with ( ), and oil tanks that have strict requirements regarding moisture cannot use ( ) for line sweeping. 196. The larger the diameter of the pipeline, the greater the pressure drop along the pipeline, but the higher the initial investment required for it. 197. The density of insulation materials should generally be lower than ( ) kg/m3. 198. The compressive strength required for insulation materials is ≮ ( ) MPa. 199. A flange connection, regardless of its size, is counted as ( ) sealing points. 200. When the leakage rate is lower than ( ), it meets the leakage standards. 201. A threaded union is counted as ( ) sealing points. 202. Product quality characteristics include five aspects: ( ), ( ), ( ), ( ), and cost-effectiveness. 203. In winter, it is necessary to strictly follow the requirements specified in the process cards; if the distance between the oil level and the heating plate is less than ( ) m, it is essential to carefully control the amount of steam supplied to the heating coil. 204. Lubricants with high viscosity have a better ( ) effect. 205. The property by which the viscosity of lubricating oil changes with temperature is called ( ). 206. The lower the ( ) property of transformer oil, the greater its safety level. 207. In winter, the temperature inside the pump room operating room should be maintained at above ( ) °C. 208. The corrosion of metals under the action of steam or gases at high temperatures belongs to ( ) corrosion. 209. The characteristic of Total Quality Management is the shift from primarily relying on ( ) in the past to primarily relying on ( ) ； From ( ) to ( ). 210. The degree of corrosion caused to metals by the corrosive substances present in lubricating oils and the oxides formed under test conditions is ( ). 211. Metal materials are damaged by corrosion in the near ( ). 212. Most metal corrosion is caused by ( ) corrosion. 213. Plating a thin layer of corrosion-resistant metal, such as chromium or nickel, on a metal surface is called ( ). 214. When drawing flowcharts, non-primary process lines should be drawn with ( ) lines. 215. Alkaline embrittlement cracking is a form of ( ) corrosion. 216. Work involving hot work for inspection and maintenance must ( ) before it can be carried out. 217. The measurement error of railway oil tank cars is ( ). 218. The limit for working at heights is a vertical distance from the ground of ( ) meters or more. 219. When working on the top of a tank, the load per square meter must not exceed ( ) kg. 220. 1 m³ = ( ) L ； 1 engineering atmosphere (1at) = ( ) Pa. 221. The performance indicators of an instrument mainly depend on the instrument’s ( ) error. 222. The type of pressure gauge that is currently widely used in pressure vessels is ( ) pressure gauge. 223. The nominal diameters of the glass tubes used in glass-tube level gauges are 15 mm and ( ) mm. 224. For a spring-type safety valve, by tightening the adjustment screw, the opening pressure of the safety valve ( ). 225. Bourdon tube pressure gauges can achieve higher accuracy; however, the pointer can only rotate within a range of ( )°. 226. For containers holding toxic, flammable, or environmentally harmful substances, ( ) type safety valves should be used. 227. The maximum range of the pressure gauge should preferably be ( ) times the operating pressure of the container. 228. Globe valves with larger diameters, higher operating temperatures, and those used in corrosive media are generally of ( ) type. 229. The pressure reducing valve that achieves pressure reduction through throttling is of the ( ) type. 230. The function of a check valve is to prevent the medium from flowing ( ). 231. The model of a certain pump is 2QYR-60/20. The meaning of its code is as follows: 2 represents ( ), Q represents ( ), Y represents ( ), R represents ( ), 60 represents ( ), and 20 represents ( ). 232. Gate valves are not suitable for use in regulating ( ). 233. Complex structure, easy wear of the sealing surfaces, and difficulty in maintenance are the disadvantages of ( ) valves. 234. Excessive vibration in a centrifugal pump is likely caused by ( ). 235. Containers exposed to corrosive media should have their ( ) measured regularly. 236. After passing the internal and external inspections in the container, what should be carried out before it is put into use? ( ) 237. Surface ( ) inspections should be conducted on areas of the container surface where cracks are suspected. 238. The error of the instrument = ( ). 239. The ( ) of an instrument is one of the important indicators for measuring its quality. 240. The 4MIE factors that affect product quality flow are ( ), ( ), ( ), ( ), ( ). 241. In automatic control flowcharts, temperature, pressure, and flow rate are represented by ( ) respectively. 242. Among various lubricant additives, the amount of ( ) additive should be the highest. 243. The algebraic difference between the instrument’s measured value and the true value is called ( ) error. 244. When implementing total quality management, it is important to adhere to the principle of \"three comprehensives and one diversity\" – that is, quality management that is （ ）、（ ） and （ ） – and the methods used must be diverse, adapted to local conditions. 245. A centrifugal pump relies on ( ) rotating at high speed to convert energy. 246. The pump that is mainly suitable for transporting viscous oils at low flow rates is the ( ) pump. 247. The pump that features high efficiency and is not significantly affected by an increase in oil viscosity is the ( ) pump. 248. If the storage temperature of additives is too high, it is easy to ( ). 249. If a pump has a displacement of 200 cubic meters per hour and the inner diameter of its outlet pipe is 147 mm, then the flow velocity at the pump’s outlet is ( ). 250. In drawing, the distance between two parallel lines should be no less than twice the width of a thick solid line; the minimum distance should be greater than ( ). 251. Turn the stationary pump shaft 3–5 times; the angle by which the shaft’s position will differ from that before turning it should be ( ). 252. For repeated measurement results, the ( ) of multiple measurements can be taken as the final measurement result. 253. When calibrating the volume of vertical metal oil tanks, there should be no residual ( ) or other deposits inside the tank. 254. The treated additives must undergo ( ) before they can be used. 255. When additives are mixed with water, the bucket lid can be opened and the mixture will evaporate naturally at a temperature of ( )°C. 256. The error that determines the precision of measurement results is ( ) error. 257. What determines the accuracy of measurement results is ( ) error. 258. As the load increases, the thickness of the lubricating oil film ( ). 259. The measurement method is a method for comparing ( ) with its unit. 260. The maximum storage temperature for antifreeze agents shall not exceed ( )°C. 261. The long-term storage temperature for T108 detergent dispersants shall not be higher than ( )°C. 262. When selecting component oils, their quality should be as close as possible to that of ( ). 263. During the use of equipment, the “four no-exceedances” refer to: no exceeding the temperature limit, no exceeding the pressure limit, ( ), ( ). 264. The methods for measuring flash point are ( ) and ( ). 265. The most widely used and primary system in petrochemical production is ( ). 266. Automation of the production process has been achieved; personnel only need to carry out ( ) on the operation of the automated devices. 267. The basis for assessing the fire hazard of oils during storage and transportation is the ( ) of the oils. 268. Automating the production process can speed up production and improve the quality of products ( ). 269. The standard instrument specifically used for calibrating non-standard meters is ( ). 270. Any instrument that reflects the measurement result based on the relative displacement or angle between a pointer and a scale is a ( ) type of instrument. 271. 0.00100 has ( ) significant figures. 272. To prevent static electricity from forming in oil products, it is necessary to ( ) during their transportation, and ( ) must be installed in oil tanks. 273. Steam fire extinguishing is a type of （ ） fire extinguishing method. 274. The error resulting from the operator’s inaccurate reading of the instrument’s scale markings is called （ ） error. 275. The minimum division of the thermometer used for measuring in lubricant tankers is ( ). 276. Increasing the number of parallel determinations can reduce ( ) error. 277. One bolt has a model of M20×80, where 80 represents the （ ） of the bolt. 278. The density is most accurately determined by the hydrometer method at ( ) °C. 279. In our country, the density of petroleum products at ( ) degrees Celsius is specified as the standard density for such products. 280. When heating condensed oil products, it is necessary to strictly control the heating rate at no more than ( ) degrees Celsius per hour. 281. Before performing hot work inside a oil tank, it is necessary to first conduct an ( ) analysis of the tank. 282. The horizontal extension of the flexible hose should be greater than ( ) meters. 283. The viscosity index of lubricating oil is determined by the viscosity at （ ）°C. 284. When taking measurements, one should ( ). 285. For train tank cars and automobiles, samples can be taken at a depth within the tank equal to () the liquid level as representative samples. 286. One of the reasons for static electricity generated during the transportation of oil products is ( ). 287. When removing the bolts from the flanges of valves (including instrument control valves), they should be loosened in the order of ( ) and ( ). Only after they have been secured with bindings can they be removed. 288. When determining the evaporation loss of lubricating oil, the heating time for the sample is ( ) minutes. 289. The sealing devices of centrifugal pumps are divided into ( ) and ( ). 290. To determine the evaporation loss of lubricating oil, the test temperature is generally ( ) °C. 291. The leakage standards for dynamic seals are light oil ( ), heavy oil ( ) ； The leakage standard for static seals is ( ). 292. Based on the causes and nature of errors, we classify errors into two major categories: ( ). 293. Methods of oil blending include pneumatic blending, ( ), ( ) and pipeline blending. 294. When 0.05657 is rounded to two significant figures, the result is ( ). 295. When checking the temperature, the temperature sensing box must first be ( ). 296. The oil tank should be measured ( ) times, and the difference between the measurements must not exceed ( ) millimeters. 297. A-grade dipsticks should be calibrated every ( ). 298. Among 250.0, 0.2500, 0.0250, and 0.0025, which one has two significant figures? 299. To shut down the pump urgently, you can first close ( ). 300. The quality manual shall include or reference the （ ） procedures, and outline the structure of the quality system documents.