1、用途

氣動(dòng)活塞直通二位切斷閥（以下簡稱氣動(dòng)切斷閥）是生產(chǎn)過程自動(dòng)化中采用的終端控制機(jī)構(gòu)，它根據(jù)控制的工作信號(hào)執(zhí)行指令，改變進(jìn)入工藝過程的介質(zhì)流量、壓力、溫度和液位等參數(shù)的調(diào)節(jié)。

氣動(dòng)切斷閥具有結(jié)構(gòu)簡單、動(dòng)作敏捷、安全可靠、維修方便及防爆等優(yōu)點(diǎn)，廣泛應(yīng)用石油、化工、電力、輕紡、醫(yī)藥、造紙等工業(yè)生產(chǎn)過程的自動(dòng)化調(diào)節(jié)和遠(yuǎn)程控制中。

2、結(jié)構(gòu)及作用原理

氣動(dòng)切斷閥由活塞執(zhí)行機(jī)構(gòu)和切斷閥兩部分組成。主要有缸蓋、彈簧、活塞、缸套、推桿、閥瓣、閥座、閥體、密封填料等零件組成。

當(dāng)輸入信號(hào)壓力通過管接頭輸入氣缸室在活塞上產(chǎn)生推力，使活塞產(chǎn)生位移并壓縮彈簧。活塞的位移帶動(dòng)推桿，閥桿和閥瓣作相應(yīng)的位移，使切斷閥達(dá)到額定的行程值。

按作用方式不同可分為氣關(guān)式和氣開式兩種，當(dāng)信號(hào)壓力增加推桿向上移動(dòng)，使閥瓣與閥座離開都為氣開式，該閥型為反作用氣開式執(zhí)行機(jī)構(gòu)。

本氣動(dòng)切斷閥結(jié)構(gòu)新穎，閥體內(nèi)的流路渦流阻力小，因而提高了閥的流量系數(shù)。閥瓣密封面采用石墨聚四氟乙烯柔性密封填料，密封性能可靠，閥的動(dòng)作由反作用氣開執(zhí)行機(jī)構(gòu)驅(qū)動(dòng)，使閥的結(jié)構(gòu)緊湊，性能穩(wěn)定良好，還可手動(dòng)旋轉(zhuǎn)氣缸頂部的手輪來調(diào)節(jié)閥瓣的行程，以適應(yīng)不同工藝的流量控制，可替代同類型的二位式薄膜切斷閥。

1、Purpose

Pneumatic piston straight-through two-position shut-off valve (hereinafter referred to as pneumatic shut-off valve) is a terminal control mechanism used in the production process automation, based on the controlled work signal, which executes instructions, change and adjust the medium flow, pressure, temperature and level and other parameters into the process.

Pneumatic shut-off valve has advantage of simple structure, agile operation, safety and reliability, easy maintenance and anti-explosion, etc., widely used in automate regulation and remote control in industrial process of petroleum, chemical, power, textile, pharmaceutical, papermaking and other.

2、the structure and principle

Pneumatic shut-off valve is composed of two parts: the piston actuator and the shut-off valve, mainly including cylinder head, spring, piston, cylinder liner, push rod, valve clack, valve seats, valve body, sealing filler and other parts.

When the input signal pressure is input into the cylinder chamber through the pipe joint, and thrust is generated on the piston, which makes the displacement of the piston and the compression of spring. The displacement of piston drives the displacement of the push rod, valve rod and valve clack accordingly, making the shut-off valve reach the rated travel value.

According to the mode of action, it can be divided into two types: air-to-close and air-to-open. When the signal pressure increases and the push rod moves upward, the valve clack leaves valve seat, which is air-to-open. This type of valve is the reaction air-to-open actuator.

The pneumatic shut-off valve has novel structure, small eddy resistance of flow path in the valve body, thus increasing the discharge coefficient of the valve. The sealing surface of valve uses graphite PTFE soft sealing packing, thus sealing performance is reliable, and the action of the valve is driven by the reaction air-to-open actuator, so the valve structure is compact, and has stable performance. Meanwhile, the adjustment of the valve clack travel can be achieved by rotating manually hand wheel on the top of the cylinder to accommodate flow control of different technologies. It can replace the same type of two-position thin-film shut-off valve.