国产日韩欧美一区二区,少妇人妻精品一二区三区,亚洲精品久久福利午夜,岛国毛片一级一级特级毛片,国产黄色片免费在线观看,国产在线播放91

 進(jìn)口調(diào)節(jié)閥的選型分析

進(jìn)口調(diào)節(jié)閥的閥體類型選擇調(diào)節(jié)閥的閥體種類很多，常用的閥體種類有直通單座（進(jìn)口氣動(dòng)單座調(diào)節(jié)閥、進(jìn)口電動(dòng)單座調(diào)節(jié)閥）、直通雙座（進(jìn)口氣動(dòng)雙座調(diào)節(jié)閥、進(jìn)口電動(dòng)雙座調(diào)節(jié)閥）、角形（進(jìn)口角型調(diào)節(jié)閥）、隔膜（進(jìn)口氣動(dòng)隔膜調(diào)節(jié)閥）、小流量（進(jìn)口小流量調(diào)節(jié)閥、進(jìn)口小口徑調(diào)節(jié)閥）、三通（進(jìn)口三通合流調(diào)節(jié)閥、進(jìn)口三通分流調(diào)節(jié)閥）、偏心旋轉(zhuǎn)、蝶形（進(jìn)口調(diào)節(jié)型蝶閥）、套筒式、球形（進(jìn)口調(diào)節(jié)型球閥、進(jìn)口V型切斷球閥）等。在具體選擇時(shí)，可做如下考慮：

(1) 閥芯形狀結(jié)構(gòu)主要根據(jù)所選擇的流量特性和不平衡力等因素考慮。

(2) 耐磨損性當(dāng)流體介質(zhì)是含有高濃度磨損性顆粒的懸浮液時(shí)，閥的內(nèi)部材料要堅(jiān)硬。

(3) 耐腐蝕性由于介質(zhì)具有腐蝕性，盡量選擇結(jié)構(gòu)簡(jiǎn)單閥門(mén)。

(4) 介質(zhì)的溫度、壓力當(dāng)介質(zhì)的溫度、壓力高且變化大時(shí)，應(yīng)選用閥芯和閥座的材料受溫度、壓力變化小的閥門(mén)。

(5) 防止閃蒸和空化閃蒸和空化只產(chǎn)生在液體介質(zhì)。在實(shí)際生產(chǎn)過(guò)程中，閃蒸和空化會(huì)形成振動(dòng)和噪聲，縮短閥門(mén)的使用壽命，因此在選擇閥門(mén)時(shí)應(yīng)防止閥門(mén)產(chǎn)生閃蒸和空化。調(diào)節(jié)閥執(zhí)行機(jī)構(gòu)的選擇為了使調(diào)節(jié)閥正常工作，配用的執(zhí)行機(jī)構(gòu)要能產(chǎn)生足夠的輸出力來(lái)保證高度密封和閥門(mén)的開(kāi)啟。對(duì)于雙作用的氣動(dòng)、液動(dòng)、電動(dòng)執(zhí)行機(jī)構(gòu)，一般都沒(méi)有復(fù)位彈簧。作用力的大小與它的運(yùn)行方向無(wú)關(guān)，因此，選擇執(zhí)行機(jī)構(gòu)的關(guān)鍵在于弄清最大的輸出力和電機(jī)的轉(zhuǎn)動(dòng)力矩。對(duì)于單作用的氣動(dòng)執(zhí)行機(jī)構(gòu)，輸出力與閥門(mén)的開(kāi)度有關(guān)，調(diào)節(jié)閥上的出現(xiàn)的力也將影響運(yùn)動(dòng)特性，因此要求在整個(gè)調(diào)節(jié)閥的開(kāi)度范圍建立力平衡。執(zhí)行機(jī)構(gòu)類型的確定對(duì)執(zhí)行機(jī)構(gòu)輸出力確定后，根據(jù)工藝使用環(huán)境要求，選擇相應(yīng)的執(zhí)行機(jī)構(gòu)。對(duì)于現(xiàn)場(chǎng)有防爆要求時(shí)，應(yīng)選用氣動(dòng)執(zhí)行機(jī)構(gòu)。從節(jié)能方面考慮，應(yīng)盡量選用電動(dòng)執(zhí)行機(jī)構(gòu)。若調(diào)節(jié)精度高，可選擇液動(dòng)執(zhí)行機(jī)構(gòu)。如發(fā)電廠透明機(jī)的速度調(diào)節(jié)、煉油廠的催化裝置反應(yīng)器的溫度調(diào)節(jié)控制等。調(diào)節(jié)閥的作用方式選擇調(diào)節(jié)閥的作用方式只是在選用氣動(dòng)執(zhí)行機(jī)構(gòu)時(shí)才有，其作用方式通過(guò)執(zhí)行機(jī)構(gòu)正反作用和閥門(mén)的正反作用組合形成。組合形式有4種即正正(氣關(guān)型)、正反(氣開(kāi)型)、反正(氣開(kāi)型)、反反(氣關(guān)型)，通過(guò)這四種組合形成的調(diào)節(jié)閥作用方式有氣開(kāi)和氣關(guān)兩種。對(duì)于調(diào)節(jié)閥作用方式的選擇，主要從三方面考慮a)工藝生產(chǎn)安全b)介質(zhì)的特性c)保證產(chǎn)品質(zhì)量，經(jīng)濟(jì)損失最小。

Control valve control valve valve valve type selection many different types of body types have commonly through single-seat, through two-seater, angular, diaphragm, low flow, tees, eccentric rotation, butterfly, sleeve type, ball and so on. In the specific choice, do the following considerations (1) spool shape and structure mainly based on the selected flow characteristics and unbalanced forces and other factors considered. (2) wear resistance when the fluid medium that contain high concentrations of wear particles in suspension, the valve's internal materials to be hard. (3) corrosion resistance as corrosive media, try to choose simple valve. (4), medium temperature and pressure when the medium temperature, high pressure and the variation shall be selected by the valve and seat materials, temperature, small changes in pressure valve. (5) to prevent steam and air steam and air produced only in a liquid medium. In the actual production process, steam and air to form the vibration and noise, shorten the life of the valve, so the choice should be to prevent the valves have valve steam and air. Valve actuator control valve to make the choice to work with the implementing agency to be able to use to generate sufficient output power to ensure a high degree of sealing and the valve open. For double-acting pneumatic, hydraulic, electric actuator, generally not reset spring. The size of the force and the direction it has nothing to do, therefore, lies in selecting executing agencies to ascertain the maximum output power and torque of the motor rotation. For single-acting pneumatic actuator, the output power and opening the valve, control valve on the emergence of the force will also affect the motion characteristics, thus requiring the entire range of valve opening to establish equilibrium. Determine the type of actuator output force of the implementing agencies to determine, based on the use of environmental technology requirements, select the appropriate enforcement agency. For the scene, explosion-proof requirements, should use pneumatic actuators. From energy considerations, should try to use electric actuators. If the adjustment of high precision, optional hydraulic actuators. Such as power plants and transparent machine speed regulation, refinery catalytic cracking unit reactor temperature adjustment control. Mode of action of control valve control valve selection in the selection of the mode of action is only when the pneumatic actuator, and its mode of action through the implementing agencies and the positive and negative effects of positive and negative role of the combination of valve formation. There are four combinations that are positive (gas-off), positive and negative (gas open type), anyway (gas open type), counter-countermeasure (gas-off), formed by a combination of these four modes of action with the gas control valve open gas off two. Mode of action for the choice of control valve, the main three aspects to consider a) process to produce safe b) characteristics of the medium c) to ensure product quality, minimize economic losses.