齒輪泵的工作原理ppt課件(編輯修改稿)
2025-01-31 21:22 本頁面
【文章內(nèi)容簡(jiǎn)介】 ? 紙墊厚度可改變齒輪端面與蓋板之間的軸向間隙。 圖 2— 5 外嚙合齒輪泵 216 典型結(jié)構(gòu) 外嚙合齒輪泵 ? 防超過額定 Pd， 裝設(shè)有安全閥 (safety valve) ? 安全閥閥體是一空心的圓柱體 ? 左端帶有錐形密封面 ? 當(dāng)作用在環(huán)形凸肩上的壓力超過彈簧值時(shí)，閥開啟，溝通排、吸兩端 ? 泵的轉(zhuǎn)向必須符合規(guī)定 ? 為防止油液外漏，設(shè)有機(jī)械軸封 ? 是廣泛使用的一種密封方式 ? 主要密封面是軸靜環(huán) 11和動(dòng)環(huán) 12構(gòu)成 ? 動(dòng)、靜環(huán)的材料分別為硬質(zhì)材料和軟質(zhì)材料做成 216 典型結(jié)構(gòu) 外嚙合齒輪泵 ? 靜環(huán)與蓋之間靠密封圈密封 ? 動(dòng)環(huán)靠彈簧壓緊在靜環(huán)上，（摩擦力使轉(zhuǎn)） ? 密封圈防動(dòng)環(huán)與軸之間漏泄 ? 安裝時(shí)手推動(dòng)環(huán)壓縮彈簧 ? 松手后動(dòng)環(huán)應(yīng)能緩緩滑出 ? 太松則漏泄量過大 ? 太緊則不能自動(dòng)滑出補(bǔ)償 ? 動(dòng)、靜環(huán)密封圈是機(jī)械密封的輔助密封元件 ? 機(jī)械軸封的基本特點(diǎn)： ? 將由填料與軸之間的徑向曲面密封轉(zhuǎn)變?yōu)閯?dòng)環(huán)與靜環(huán)間的軸向端面密封。 216 典型結(jié)構(gòu) 外嚙合齒輪泵 ? 與填料密封相比，機(jī)械軸封的主要優(yōu)點(diǎn)是： ? (1)密封性能好 ? (2)使用壽命長(zhǎng)。 ? (3)摩擦功耗少。 ? (4)軸或軸套基本不被磨損 ? (5)適用范圍廣，（用于高溫、高壓、有毒或有腐蝕性） Mechanical seals(1) ? The provision of rotary shaft seals instead of the usual stuffing box and gland, where conditions are suitable, possesses many advantages. ? The power absorbed is lower and is constant, whereas a gland excessively tightened causes a considerable increase in power absorbed. ? In small pumps this may result in overloading the motor. Mechanical seals(1) ? In addition maintenance costs are reduced, the rotary seal operating for long periods without wear or attention. ? A standard seal consists of a stationary carbon ring insert in the casing, or seal cover where such is provided, and against this a metal ring of easy clearance on the shaft sleeve rotates, contact between the faces being ensured by a lightly loaded coil spring. Mechanical seals(2) ? The rubbing faces of both carbon and metal rings are independently lapped to give a dead flat surface. ? A synthetic rubber ring, of circular crosssection, contained between shaft sleeve and metal ring, in a groove in the latter, effectively prevents leakage between them. ? The diameter of the groove is such that a squeeze is exerted on the rubber ring, thus a sufficient frictional force is provided to rotate the metal ring, with certain e
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