由(yóu)于各(gè)螺杆的相(xiàng)互齧(niè)合以及螺杆與(yǔ)襯筒内壁(bì)的緊(jǐn)密配(pèi)合(hé)，在(zài)泵的(de)吸入口和(hé)排出口之間，就會被(bèi)分隔(gé)成一(yī)個或(huò)多個(gè)密封空間(jiān)。随着(zhe)螺杆的轉(zhuǎn)動和齧合，這些(xiē)密封空間(jiān)在泵(bèng)的吸入端不斷(duàn)形成，将(jiāng)吸(xī)入室(shì)中的(de)液體(tǐ)封入(rù)其中(zhōng)，并自(zì)吸入(rù)室沿螺杆軸向(xiàng)連續地(dì)推移至排(pái)出(chū)端，将封閉(bì)在 各(gè)空(kōng)間中的液體不斷排出，猶如一螺母在(zài)螺紋(wén)回(huí)轉時被(bèi)不斷向前推進(jìn)的情形(xíng)那樣(yàng)，其(qí)中螺(luó)紋圈(quān)數看做液體，當螺釘(dìng)旋轉時螺紋在轉(zhuǎn)動時就相當(dāng)于液體在螺杆(gǎn)泵裡面的(de)情形，這就是(shì)螺杆泵的基(jī)本工作原(yuán)理。螺杆與殼體(tǐ)之間的(de)密封(fēng)面(miàn)是一個空間曲面。在(zài)這個曲面(miàn)上存在着諸如ab或(huò)de之(zhī)類(lèi)的(de)非密(mì)封區，并且與螺杆的凹(āo)槽部分(fèn)形成許多三角形的(de)缺口abc、def。這些(xiē)三角(jiǎo)形 的缺口(kǒu)構成(chéng)液(yè)體(tǐ)的通(tōng)道，使(shǐ)主(zhǔ)動(dòng)螺杆凹槽(cáo)a與從動螺(luó)杆上的凹槽b、c相連通。而凹(āo)槽b、c又(yòu)沿着(zhe)自己(jǐ)的螺(luó)線繞向背(bèi)面， 并(bìng)分别和背(bèi)面的(de)凹槽(cáo)d、e相連通。由(yóu)于在(zài)槽d、e與槽f(它(tā)屬于另一頭螺(luó)線)相銜接(jiē)的密(mì)封面(miàn)上，也存在(zài)着類(lèi)似(sì)于(yú)正面的三角形缺口(kǒu)a’b’c’，所以d、f、e也将相(xiàng)通。這樣，凹槽abcdea也就(jiù)組成一(yī)個“∞” 形的密封(fēng)空(kōng)間(如采(cǎi)用單頭螺紋，則凹槽(cáo)将順軸向(xiàng)盤饒螺杆(gǎn)，将吸(xī)排口(kǒu)貫通，無法(fǎ)形成(chéng)密封)。不難(nán)想(xiǎng)象(xiàng)，在這樣的(de)螺杆(gǎn) 上，将形(xíng)成許多個獨(dú)立的(de)“∞”形密(mì)封空間，每(měi)一個密(mì)封空間所占有的(de)軸向長度恰好等于(yú)累杆的導(dǎo)程t。因(yīn)此，為了使螺杆能吸、排油(yóu)口分(fèn)隔(gé)開來，螺杆的(de)螺紋段的(de)長度至少(shǎo)要(yào)大(dà)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.