由(yóu)于各(gè)螺杆的相(xiàng)互齧合以及螺杆與(yǔ)襯筒内壁的緊(jǐn)密配(pèi)合，在泵(bèng)的吸入口和(hé)排出口之間，就(jiù)會被分隔(gé)成一個或多個(gè)密封(fēng)空間(jiān)。随着螺杆(gǎn)的(de)轉動和(hé)齧合，這些(xiē)密封空間在泵(bèng)的吸入(rù)端(duān)不斷(duàn)形(xíng)成，将吸入室(shì)中的液體(tǐ)封入(rù)其中，并自(zì)吸入室沿螺(luó)杆軸向連續(xù)地推(tuī)移至排出端，将(jiāng)封閉(bì)在 各空間中的(de)液體不斷(duàn)排出(chū)，猶如一(yī)螺(luó)母在螺紋(wén)回轉時被(bèi)不斷向前(qián)推進(jìn)的情(qíng)形那(nà)樣(yàng)，其中螺紋(wén)圈(quān)數看做液體，當螺釘(dìng)旋轉(zhuǎn)時螺(luó)紋在轉動時(shí)就相當(dāng)于液(yè)體在(zài)螺杆(gǎn)泵裡(lǐ)面的情形(xíng)，這就是螺杆泵(bèng)的基(jī)本(běn)工作原(yuán)理。螺杆與(yǔ)殼體(tǐ)之間的密(mì)封面(miàn)是一個空間曲(qǔ)面。在這個曲面(miàn)上存(cún)在着諸如(rú)ab或de之(zhī)類的非密(mì)封區(qū)，并且(qiě)與螺(luó)杆的(de)凹槽部分形成許多三角(jiǎo)形的缺(quē)口abc、def。這些(xiē)三角形 的(de)缺口構成液體的通(tōng)道，使主動螺杆(gǎn)凹槽(cáo)a與(yǔ)從動螺(luó)杆上(shàng)的凹槽b、c相連通。而(ér)凹槽b、c又(yòu)沿着自(zì)己(jǐ)的螺(luó)線繞(rào)向背面， 并(bìng)分别和背面的(de)凹槽(cáo)d、e相連(lián)通。由(yóu)于(yú)在槽d、e與槽f(它(tā)屬于另一頭螺線)相銜接(jiē)的密(mì)封面(miàn)上，也存在(zài)着類似于(yú)正面的三(sān)角形缺口(kǒu)a’b’c’，所以d、f、e也将相(xiàng)通(tōng)。這樣(yàng)，凹槽(cáo)abcdea也就(jiù)組成一個(gè)“∞” 形的(de)密封(fēng)空間(如采用單(dān)頭(tóu)螺紋，則(zé)凹槽(cáo)将(jiāng)順軸向(xiàng)盤饒螺杆，将吸排口(kǒu)貫(guàn)通，無法(fǎ)形成密封(fēng))。不難(nán)想(xiǎng)象(xiàng)，在這(zhè)樣的(de)螺杆(gǎn) 上，将(jiāng)形成許多個獨立的(de)“∞”形密(mì)封空(kōng)間，每(měi)一個(gè)密封(fēng)空間所占有的軸向長度恰好等(děng)于(yú)累杆的導(dǎo)程t。因此，為(wéi)了使螺杆(gǎn)能吸、排(pái)油(yóu)口分(fèn)隔開來(lái)，螺(luó)杆的(de)螺紋(wén)段的(de)長度至少(shǎo)要大于一(yī)個導程(chéng)。due to the mutual engagement of each screw and screw and the close coordination of the liner wall, between the inlet and outlet of the pump, can be divided into one or more of the sealed space.with the rotation of the screw and the meshing, the sealed space in pump suction side form unceasingly, the liquid from the suction chamber seal in among them, and the suction chamber along the screw axial continuously goes on to the discharge end, will be closed in the space of the liquid discharge, like a nut in screw rotation being constantly move forward, the screw thread turns as liquid, when screw rotating screw rotation is equivalent to the liquid in the inside of the screw pump, this is the basic work principle of screw pump.the sealing surface between screw and shell is a space curved surface.exist on the surface of the sealing section, such as ab or de and screw groove part of the form many the gap of the triangle abc, def.these triangular gap formation fluid channels, make active screw groove with a driven screw groove on the connected to b and c.and groove b, c and along their spiral around to the back, and, respectively, and on the back of the groove connected to d and e.due to the tank d, e and f (it belongs to another head spiral) of corresponding seal surface, there are also similar to the positive triangle gap a 'b' c ', so d, f, e will also is same.so, grooves abcdea on forming a "up" form of the sealed space (such as using single thread, axial disc groove will arrange spare screw, connecting the suction paikou, unable to form a seal).it is not hard to imagine that in this kind of screw, will form a number of independent "up" form sealed space, each of the sealed space occupied the axial length equals the tired stem lead t.therefore, in order to make the screw suction and discharge of oil can be separated, the length of the screw thread of at least than a lead.