200521330 九、發明說明： 【發明所屬之技術領域】 本i明有關於乾式幫浦’尤特別有關於典型他使用在真 空應用中的羅茨（Roots)、諾塞（Northey或「爪式」）、及螺 疑幫浦。本發明係針對以上各型幫浦的操作之改良。 【先前技術】 式幫浦廣泛使用在工業製程中，用以提供產品製造· 月乎又/或低壓的王衣境。應用場合包括製藥及半導體製造』 $ &種幫/•包括一主要的乾式(或無油的)幫抽機構，但每 书還包括若干組成件，例如軸承及傳動齒輪，用以驅動寄 幫抽機構，並為具效率起見還需要潤滑的。 納入羅次及/或诺塞型機構的乾式幫浦，通常是多段式的 正位移幫浦’在各真空室中採用兩個互喊的轉子。該兩轉 子在各室中可具有相同型式的外形，或各室各有不同的外 形0 一興型的螺旋型㈣機構包括兩個平行㈣設置的輕 二各含有一外螺紋轉子，兩軸桿係使其兩轉子的螺紋互 、 冑庸本體中。在互嚙各點兩螺紋之間， 父及螺紋與幫浦本體（其作用口一 公差，使得在…人的氣體容量：=的緊密 盥 延捕獲在兩轉子螺紋 ，、内表面之間’從而在兩轉子旋轉時將 :。該基本的螺旋幫浦機構已有多種所周知的修改= ':已有螺旋型幫浦’其具有節距變動的螺紋及/或機 ”中累、··文的高度（或外直徑），在從—幫浦人H浦 97335.doc 200521330 f 口的方向上成呈減小地尖縮。就後者情況來說，兩轉子 是裝設在定子的尖縮狀内腔中。 田私作乾式幫浦到達一多半是極低於大氣壓力的需要 壓力（「最終麼力」）時，較佳地’所需用於操作該幫浦的功 率已予減小到最低程度。該幫浦排出容量的大小，對於在 最終塵力下所需用於操作—幫浦的輸人功率，具有相當大 的影響力。藉内建幫浦一入口容積對出口容積的高容積比 率，該輸入功率可在最終堡力了維持得很低。㈣安排的 缺點’是當幫浦的入口壓力增加到大氣壓力時，對於幫浦 的輸入功率要求，會有顯著的增加。 、在早先技藝中，高幫抽的内部壓力已予免除，藉助在幫 4内α卩加入一吹洩閥；該吹洩閥可起動以釋放壓力及防止 幫浦内過分的壓力增加。在某些情況下，這些閥門的性能， 可能會受到積聚在密封表面上或附近的處理介質的不良影 響，降低了壓力增強予以解除的效率。 【發明内容】 根據本發明的一態樣，提供一種乾式幫浦，包括一定子， 孩疋子内凌有適於在定子内互嚙而作相反旋轉的第一及第 -轉子’該幫浦還包括用以引起兩轉子在定子内作軸向移 、矿置在幫庸使用時，用以改變至少一個介於兩轉子 和定子之間的間隙。 舉例來說，在對幫浦内部操作情況的即時反應下，主動 控制兩轉子在定子内的轴向位置，可使一在兩轉子和定子 之間的間隙，按照幫浦使用中之所需，予以增加、降低、 97335.doc 200521330 或維持在一定常的水準下。舉例來說， : 的或多灰塵的大氣之後予以關掉時，兩轉子到定= 題::Π ’甚至予以最大化’以防止在重新啟動時問 =2生。在操作中，㈣子和U之間的轴向間隙可能 =處理沈積物’而當幫浦停㈣，轉子將會冷卻而收縮 -理沈積物上，有可能會鎖死幫浦。當幫浦停止時，使 轉子相對定子移動，能使軸向間隙增加，從而 新起動的機率。幫浦-經起動，該轴向間隙即刻降回到幫 浦操作中的正常運轉間隙。 間能予主動更 上的處理沈積 替代或外加的作法，兩轉子在幫浦使用期 接近定子表面移動，以刮除聚積在定子表面 物0 轉子収子的間隙，也可針對不同的幫抽氣體種類，予 以控制以使幫浦工作表現趨於完善。舉例來說，當幫抽氫 氣或-種如氬氣的惰氣時，f亥間隙可予以增加或減小，以 達到最佳情況的工作表現，不致有幫浦卡死不動的發生。 兩轉子在定子内的㈣，能顯著降低各種的操作變數， 諸如回壓、運轉溫度、及氣體型態等對於幫浦工作表現的 影響。此外，主動控制轉子位置的能力，可以鬆解各組成 件的製造精確度。這樣可以使成本顯著減低，由於免除了 可能的研磨作業及降低了擦刮等級。 舉例來說’在-個具體實施例中，幫浦包括在其操作期 間用於引起轉子軸向移動以回應兩轉子所產生的軸向荷載 的裝置。當操作中，幫浦内部的内壓力在轉子上產生一軸 97335.doc 200521330 二 荷冑$個推力荷載，是和正由該幫浦執行的氣體 【縮工作虿成正比例，而因此也和該幫浦的輸入功率要求 成正比。舉例來說，一螺旋幫浦的氣體壓縮效率，是大大 也又到"於衣載螺紋轉子的定子的内側表面、和兩轉子本 身之間的間隙的控制。在兩轉子呈尖縮狀的場合，轉子可 予同時又同步地離開定子表面移動，有效地增加徑向間 隙，降低壓縮作用，並因而降低功率輸入的要求條件。同 樣也漸夂的羅次（Ro〇ts)型轉子，可同時而又同步離開定 子表面移動，有效地增加徑向間隙，降低壓縮作用，並因 而降低對功率輸入的要求條件。 ，各轉子是典型裝設在_個別的軸桿上（或與其一體成 型），該軸桿則以可旋轉方式被裝設在幫浦内，該幫浦包括 1承總成’用於成可相對定子旋轉方式支持兩轴桿。在 較佳^具體實施例中，用於引起兩轉子在定子内作軸向移 、、才置係由用於相對定子移動軸承總成的裝置所構 、丨士在具體貫轭例中，該軸承總成可在殼體内一 σ自由#夕動’ 5亥用於引起兩轉子軸向移動的裝置包括 一^簣機構，其相對於一轉子而被配置成可在當該轉子承 受一轴向荷載時，該彈簧機構會收縮或伸張，引生一轴向 的反作用荷載。 當有-轴向荷載在-轉子上產生，而有引生轉子與抽承 總成的轴向移位的傾向時’該彈簧可受邀縮或伸張（視其位 置而定）。假定荷載未超過該彈簧的彈性極限，該彈筹將反 作用以變動轉子的軸向位置。藉選定—具有適當彈箬常數 97335.doc 200521330 的彈簧，此項安排可用於變動轉子對定子的間隙，在一寬 廣的入口壓力範圍巾，給與一相對定常水準的氣體壓縮工 作’從而，減緩對幫浦功率輸入的要求。 在其它具體實施例中，幫浦包括控制裝置，用於主動控 制引起兩轉子軸向移動的裝置的操作。舉例來說，一活塞 或其它引動器可專為移動轉子設置，該控制裝置則控制引 動裔的移動來控制兩轉子的轴向位置。在較佳的具體實施 例中，該控制裝置控制一配適成可轉動一驅動軸的馬達， 該驅動軸與引動器啣接，以致藉助驅動軸的旋轉，可在軸 向上相對定子移動引動器。該驅動軸可以，舉例來說，包 括 $螺杯，其係經由一在引動器上的相符螺紋孔徑穿 過。另一作法，控制裝置可由一或多個的電磁鐵構成，用 以移動引動器。 用於準確相對定子移動兩轉子的任何其它便利機構，可 予設置。例如，可設置一壓電引動器，其可在回應一由控 制裝置供給引動器的電壓下變形。另一作法，可設置一金 屬環、管、或其它元件，由控制裝置給予選擇性的加熱， 以使该元件終結的熱膨脹引起兩轉子在定子内移動。可就 兩轉子相對定子所需移動的程度，選擇最適當的機構。例 如’對於諾塞型轉子來說，該最大的需要移動量可小於1〇〇 微米’而對於尖縮形的螺旋轉子來說，所需要的移動量可 在1毫米左右。 在兩轉子的移動是由軸承總成相對定子的移動所引起的 場合’引動器可權宜地包括部分的軸承總成殼體，或由該 97335.doc -10- 200521330 办又脰來承載。该軸承總成殼體，較佳地，含有一幫浦用的 内側密封機構。這個軸承總成，較佳地，是支持各軸桿的 一端’設置第二軸承總成來支持各軸桿的另一端。這個轴 承總成可關於定子加以固定，或安排成可與軸桿一齊移 =。後者的第二軸承總成的殼體，也可含有一 f浦的^ 密封機構。這樣可以確保軸桿相對定子的移動不致損害到 内側幫浦密封。 兩軸承總成的殼體之一者或兩者，可界定一定子的端表 面’以致在兩轉子的軸向位置予以㈣時，㈣表面隨著 兩軺子一齊移動，從而，藉在兩轉子的端頭和定子的端表 面之間維持一不變的間隙’可避免兩轉子的端頭和定子的 端表面之間發生碰撞。 該控制裝置可予配置成適於接收一表示冑浦操作參數之 信號，並適於依靠該一信號控制兩轉子的軸向位置。該操 作參數可包括定子及/或定子内部之溫度、啟動時之最終真 空校準、回壓、排氣溫度、功率消耗、及入口壓力等中之 -。在關於溫度方面，冷卻水的失效很可能產生一問題， 即熱衝擊將扭曲定子到使得轉子和定子接觸的程度。藉由 量測定子溫度及進水溫度，是可能偵測出一卡死不動情況 的啟始，並在熱衝擊發生時藉由增加轉子至定刊的間隙 以㈣該幫浦。高回壓可導致内部氣體溫度的增加及轉子 至定子的差別，而此將可能引生幫浦的咬死現象。藉由量 冽内側之氣體溫度’將可變更轉子至定子的間隙以緩和回 壓的增加。在關於功率消耗方面，該控制裝置可配置成可 97335.doc -11 - 200521330 接收-表示用於旋轉該等轉子之一馬達的功率消耗之信 號，並可控制該引動器的引動動作以回應該信號。 可替代地，或除此之外，該控制裝置可包括-感測器以 供摘測介μ子和轉子之間的間隙大小或變更速率且該 控制衣置被配置以控制一用於回應一來自感測器的輸出而 引動轉子之軸向移動的裝置。該感測器可很方便地以—霍 爾效應（HaU effect)感測器供備。該感測器可藉由確定轉子 在幫浦内奴子成零軸向間隙時的位置而被予校準。這可 在栗浦使用前或-旦該幫浦已暖機以導致熱效應時藉由轴 向地移動轉子直到接觸發生為止（該等轉子係不旋轉的）而 予以達成。或者，將這些熱效應建入控制裝置中，以致當 根據輸出自該感測器之信號以決定一軸向間隙的大小時； 將這些熱效應考慮在内。 該引起轉子作轴向移動的裝置較佳地被配置成可確保兩 轉子都維持在相同的軸向位置上，但也可配置成可容許兩 轉子間有相對的軸向移動。典型地，這種相對運動會在轉 子接觸的兩極限範圍内，並可配合兩轉子而用於刮除聚積 在兩轉子側面上之處理介質的操作中，或可作定時的微 調。兩轉子間的相對運動可藉使用可供引動各轉子軸向移 動的獨立裝置而予以實現，例如前述之各別的引動器設 置。一相關的控制裝置可經配置成用以引動兩轉子互相獨 立的移動。這可在兩轉子是靜止時藉由監控一轉子的可達 到動程而予以達成，或在兩轉子全速運轉時藉由監控軸桿 扭矩或馬達電流而予以達成。 97335.doc -12- 200521330 在兩轉子具有互㈣紋的場合，至少部分的螺紋，較佳 地具有-外直彳！，其在—從該m σ _幫浦出口之方 向上呈減小的尖縮狀。在一具體實施例中，各螺紋具有— 從該幫浦人口到出口呈漸減的直I在另—具體實施例 中，各轉子只有部分的螺紋具有一朝向該幫浦出口逐漸變 小的外直徑，螺紋的其餘部分具有—大致不變的外直徑。 有許多的優點特別與上述後者具體實施例相關聯。首:， 真空幫浦排出氣體的溫度是隨著運轉情況變動，並會影響 到在幫浦的排氣（低真空）端轉子到定子的間隙。在排氣階段 對轉子収子間㈣㈣可容許有性能及㈣消耗達到^ 佳化的情況。入口(高真空)溫度並未像出口那樣顯著變化， 而因此在入口階段之轉子到定子的控制是較不重要的。其 次，在粗重操作（在於或接近大氣壓力下抽没大量的氣體） 期間’藉由迴避幫浦的低真空階段而可使性能最佳化。在 排氣階段中之轉子到定子的間隙可予增加以作用如同一茂 壓閥，而在人口階段的轉子到定子的間隙維㈣常不變以 使抽汲效率最大化。在兩轉子(至少部分)呈尖縮狀的場合， 轉子和定子之間的徑向間隙的大小可藉由轉子和定子之間 的軸向間隙的大小而予以決定。軸向間隙和徑向間隙之間 的關係可在測試中被予建立。 兩轉子可在兩軸向位置之間作脈動，以便移除介於轉子 和定子間之軸向間隙中的處理沈積物。例如，該控制裝置 可破配置成以第一速度在一軸向方向上移動兩轉子，以增 加在轉子和定子間的轴向間隙，独―不同於第一速度的 97335.doc -13· 200521330 移動兩轉子’以減少在轉子和定子之間的軸向間 .....P方止幫浦馬達的跳機，軸向間隙的減少速率較俨 地是大於軸向間隙的增加速率。一線性解碼器可備以防: 兩轉子卡死在軸向位置的兩極端上。 在一第二態樣中，本發明提供—種控制-幫浦之操作的 t法，：幫浦包括一定子’其内裝有適於在定子内作相反 疑轉的弟-和第二互嚙轉子；該方法包括以下步驟：當兩 轉子係在靜止不動時，相對於定子而軸向移動兩轉子以 增加兩轉子和定子間的軸向間隙；隨後起動轉子旋轉；以 及在轉子旋轉期間’相對於定子而軸向移動兩轉子，以減 小兩轉子和定子間的軸向間隙。 《尚包括在幫浦使用期間接續地（較佳地係重覆地） ,、 減1軸向間隙的步驟，俾使將沈積物移離軸向間 \ 士疋在本發明的第三態樣中，提供一種控制一幫浦 紅作的方法’ $幫浦包括一定子，其内裝有適於在定子内 作相反旋轉的第_ ^ I _ = 土 & β 矛第一互嚙轉子；該方法包括連續在相 的軸向上相對於定子而移動兩轉子的步驟，以週期性變 兩轉子和定子間的轴向間隙，並將沈積物移離轴向間隙。 、斤陳述的關於本發明第一態樣的各項特色，同等地 適用在/發明的方法態樣；反過來說也是正確的。 本土月之右干具體實施例，將以舉例說明方式，進一步 參照後附圖式加以解說。 【實施方式】 參照圖1至4，^ ^ 1 η ^ 幫浦10包括一幫浦本體12，具有一界定第 97335.doc -14- 200521330 一部分14及第二部分16的幫抽腔室18。一通至腔室18的流 體入口 20，製作在幫浦本體12的第一部分14中，及一出自 腔室18的流體出口 22,製作在幫浦本體12的第一部分16令。 幫浦10尚包括一第一軸桿24，及一與第一軸桿間隔並平 行設置的第二軸桿26。兩軸承28是為支持軸桿24、26而設 置。軸桿24、26經配適可圍繞各自的縱長軸線在相反方向 上旋轉。兩軸桿之一 24係經由一驅動機構32連接到一驅動 馬達30 ;兩軸桿係藉正時齒輪聯結在一起，以致在使用中 兩軸桿24、26是在相同的速度下、但在相反的方向上旋轉。 一第一轉子34是為在腔室18内作旋轉運動的目的而裝設 在第一軸桿24上，而一第二轉子36是為同樣的目的裝設在 第二軸桿26上。兩轉子34、36各具一逐漸變尖的形狀，並 具有螺旋槳或螺紋38、40,分別製作在兩轉子的外表面上， 兩螺紋如圖所示是互相。齒合的。 在這個具體實施例中，兩轉子34、36的螺紋38、40各具 有一外直徑，在從幫浦1〇入口 2〇到出口 22的方向上成減小 的尖縮狀，，而幫抽腔室18，其在幫浦的使用中作為定子使 用的，作相符的朝幫浦出口 22方向逐漸變小。兩轉子34、 36的形狀，特別是螺紋38、4〇彼此相對及相對幫抽腔室u 的形狀，是經過規劃，要確保和幫抽腔室18的内表面具有 緊密的公差。 ~ 為要控制兩轉子34、36在幫抽腔室18中的軸向位置，該 幫浦1〇包括兩軸承總成42，各成可滑動方式裝設在各自 的、位於幫浦10排出端的圓柱形殼體44中，如在圖5至7中 97335.doc -15- 200521330 有更詳細的顯示。各圓柱形殼體44是緊固到各自的軸桿 24、26上，該兩圓枉形殼體44是藉助一連接臂牝互相連接。 各軸承總成42係由—雙角面接觸轴承48所組成，兩後者 成背對背的構型安置，用以維持穿通過轴承總成42的轴桿 24相對幫浦本體12的橫向位置、然而又可容許該軸桿的轴 向移動及圍繞其縱轴線的旋轉。在轴承48的外表面和圓柱 形殼體44的内表面之間，置備有一小間隙。該圓柱形殼體 44和幫浦本體12之間還有一個小小的軸向間隙，這個間隙 讓初始間隙在幫浦組合過程中，藉在幫浦本體和各個圓柱 形殼體44的夹合凸緣5〇之間放置薄片材料，可予以固定。 落位在軸承48和圓柱形殼體44的端壁52中間的是一間隔 % 54和彈貫56。軸承48是藉助一夾合環58予以留置在殼 體44中以致在彈黃56上的設定一適合於運轉荷載情況（及 ^浦的輸入功率）的預置荷載。端壁52是在徑向上内向一軸 % 6〇伸展，軸環60形成為將圓柱形殼體44緊固到軸桿的緊 固總成的一部件。 在使用中由幫浦丨〇所執行的壓縮工作，導致產生一傾 向於在自出π 22到人口 2G的方向上移動兩轉子34、36的袖 向何載。該轴向荷載緊抵彈簧56作用，以使兩轉子34、36 在轴向上f多動，從而，與軸向荷載成正比例地改變在兩 轉子34 36的螺紋38、4〇和定子之間的徑向間隙。藉變更 特徵彈性率，暂、、者&私、,^ ;庸的輸入功率能予以修裁到適合在幫浦速 度範圍中—特^用it。在兩轉子34、36的軸向荷載有任何 差别存在日寸，將兩圓柱形殼體44堅固連接在一起的連桿 97335.doc -16 - 200521330 46，可確保兩轉子同時予以重新定位，萬一兩轉子變得彼 此相對排列不正確時，可避免任何可能發生在轉子μ、％ 的兩螺紋38、40之間的干擾。 在圖1至7中的具體貫施例的一變型中，兩轉子的軸向位 置是由氣壓控制的活塞來操控。活塞的移動可由—控制機 構來刼控’該控制機構可包括一壓力感測器，其可偵測到 在-給定轉子軸線上的軸向荷载，並可引起一藉助活塞施 的反作用力。此外，該控制器可予配置成容許活塞的獨 立移動，因而容許兩轉子使用在其它用嬖 圖8示-螺旋幫浦之第二具體實施例，具㈣動^兩除轉 子在定子中的位置的能力。相同於第一具體實施例，幫浦 ίο包括一界定一幫抽腔室74的幫浦本體72，流體入口％: 及流體出口 78。該幫浦70尚包括一第一軸桿肋及一盥第— 軸桿平行且間隔設置的第二軸桿82。第一軸承總成以係為 支持兩軸桿80、82的上端而置備（如圖8中所示而設 軸承殼體88内部的第二軸承總成％係為支持兩軸桿如 的下端而置備。兩軸桿80、82係經配適在歯輪箱Μ内環铸 縱長軸線在相反旋轉方向上旋轉。兩軸桿之—⑼二 驅動機構連接到-驅動馬達（未圖示），兩轴桿係藉_ = 窗輪9〇聯結起，致使在使用中兩轴桿80、82是以相同才 的速度、但是在相反的方向上旋轉。 ° 一第一轉子92是為在腔室74内作旋轉運動而 軸二而一第二轉子36是為同樣目的裝設在： 兩轉子92、94各在—具有大抵_形狀的人口 76翻 97335.doc -17- 200521330 近具有ϋ分，並在—具有漸縮形的出口 78鄰近具有 一第二部分。各轉子具有一螺旋槳或螺紋％、98，分別製 成在其外表面上，兩螺紋如圖所示是互相嚙合的。 兩轉92、94的螺紋96、98，在各轉子的第一部分上具有 一大致不變的外直徑，而在各轉子的第二部分上具有一朝 向幫浦70出口 78方向逐漸變小的外直徑。幫抽腔室74的内 表面，其在幫浦的使用+作用如同一定子者，是符合兩轉 子的外直徑形狀來製作的。 為要控制兩轉子92、94在幫抽腔室74内的軸向位置，幫 浦74包括一伺服馬達1〇〇，轉動一附接在馬達上的導螺桿 1〇2。該導螺桿1〇2和一在軸承殼體88上製有相符螺紋的孔 徑104嚙合，以使該軸承殼體88作用如同一活塞，相對幫抽 腔室74作軸向移動，以控制在幫浦7〇尖縮狀部分上的轉子 對定子的間隙。伺服馬達100的引動可用任何適當的機構來 控：。舉例來說，一感測器106(例如一霍爾效編 可提供該馬達100、或（如例圖中所示）一分立的馬達控制器 1〇8—表示在於兩轉子和定子之間的軸向間隙大小#或變 更速率）的信號；馬達100的操作，係根據接收自感測器1〇6 的信號加以控制，俾按需要在軸向上移動馬達以增加或減 少軸向間隙的大小。 在這個第二具體實施例中用於相對定子軸向移動轉子的 機構，當然，是能用於移動具有全部是尖縮狀螺紋的轉子， 如同在第一具體實施例中所用的。在圖9所示的第三具體實 施例中，這個機構是用來軸向移動含有非尖縮狀螺紋'112的 97335.doc -18- 200521330 轉子110 ’並因此可以控制在轉子11()和定子114的端表面 116、118之間的軸向間隙’用於，作為舉例，刮除定子兩 端的處理/1貝’及預防再啟動時的失效。在這個具體實施 例中’该固定的軸承總成84已用一浮動的轴承總成代替， 其中兩軸承係設置在軸承殼體12〇内，後者係隨著轉子 的軸向移動而在軸向上移動。介於軸承本體12〇的外牆壁 122和齒輪箱83的兩牆壁124之間的緊密公差，是作為控制 該軸承殼體12〇的徑向位置之用，該軸承殼體12〇的外牆壁 122載有流體密封機構（未圖示），用以阻止油類之從齒輪箱 83進入幫抽腔室126。軸承總成％的殼體以載有一類似的密 封機構（未圖示），用以密封幫抽腔室126。 在圖10的具體實施例中，螺紋轉子110已用諾塞型轉子 130置換，以提供一種多段式的正位移幫浦，藉轉子的軸向 移動，控制在於兩轉子130表面和相對的定子132表面之間 的間隙。 圖11顯示一種具有羅茨型轉子140的乾式幫浦。羅茨型轉 子140，相似-於第一具體實施例中的螺紋，在從幫浦的入口 到出口的方向上逐漸變小；定子142的内表面順從地向幫浦 出口逐漸文小。在這個具體實施例中，轉子i40的軸向移動 控制著在於轉子140和定子142之間的徑向間隙。在這個具 肢只^例中，在於兩轉子端頭和容納兩轉子的幫抽 腔室的端表面144、146之間的軸向間隙，是用兩轉子相對 該定子142的軸向移動，維持在大致定常不變。如在圖丨工中 所不，兩端表面144、146係由支持軸桿8〇、82端頭的殼體 97335.doc -19- 200521330 146隨著兩轉子14〇移 88、120所界定，以致兩端表面ι44 動0 在圖8至U中，用於在轴向上相對定子移動轉子的機構， 是定置在幫浦的低壓力（入口）端。可是，這個機構可換以定 置在幫浦的高壓力（出口）端。 此外，雖在圖8至U所示的具體實施例中，軸向間隙是由 感測器106來監控，幫浦的其它操作參數，像是回壓、排出 溫度、功率消耗、及/或入口壓力，可轉送到控制器1〇8， 或直接傳送到馬達100，供作控制轉子在幫浦70使用中的 軸向位置之用。這種信號可從適當定置的感測器輸出；適 宜時，或從驅動轉子旋轉的馬達輸出。 除在回應輸出自這些感測器的信號下控制轉子的軸向位 置以外，其它的操作參數，也可在回應這些信號下加以調 整。舉例來說，供給到伸展在定子周圍的冷卻夾套或其它 熱傳裝置的冷卻水，其溫度及/或流率可視間隙的大小予以 調整，以使該定子能跟上轉子的膨脹及收縮的步調· 综合言之_，目前提供一種乾式幫浦，其包括一定子，内 裝有第一及第二互嚙轉子，經配適在定子内作相反旋轉， 並包括用在幫浦使用當中，主動控制轉子在定子内的軸向 位置。 【圖式簡單說明】 圖1為一螺旋幫浦之第一具體實施例之側視圖； 圖2為圖1中幫浦之平視圖； 圖3顯示一通過圖1中平面b-b之剖面； 97335.doc -20- 200521330 圖4顯示一通過圖2中平面A_A之剖面； 05為引起圖丨幫浦中兩轉子軸向移動之裝置之平視圖； 圖6顯示一通過圖5中平面a_a之剖面。 圖7為引起圖丨幫浦中兩轉子軸向移動之裝置之一透視 圖； 圖8顯示一通過螺旋幫浦第二具體實施例之剖面； 圖9顯示一通過螺旋幫浦第三具體實施例之剖面； 圖10顯示一通過一諾塞（Northey)幫浦實施例之剖面； 圖11顯示一通過一羅茨（Roots)幫浦實施例之剖面。 【主要元件符號說明】 10、 70 幫浦 12、 72 幫浦本體 14 第一部分 16 第二部分 18、 74、 126 幫抽腔室 20、 76 流體入口 22、 78 一 流體出口 24、 26、 80、 82 軸桿 28 轴承 30 驅動馬達 32 驅動機構 34 > •36、 > 92、 94 、 110 轉子 38、 _ 40、 ‘ 96〜 98 螺紋 42， •84 > -86 軸承總成 97335.doc -21 - 200521330 44 46 48 50 52 54 56 60 83 88 、 120 90 100 102 104 106 108 112 114 、 132 、 142 116 、 118 、 144 122 124 130 140 d 圓柱形殼體 連接臂或連桿 角面接觸軸承 夾合凸緣 端壁 間隔環 彈簧 軸環 齒輪箱 軸承殼體 正時齒輪 伺服馬達 導螺桿 孔徑 感測器 控制器 非尖縮狀螺紋 定子 146 端表面 外牆壁 牆壁 諾塞型轉子 羅茨型轉子 軸向間隙大小 97335.doc -22-200521330 IX. Description of the invention: [Technical field to which the invention belongs] The present invention relates to dry pumps, especially to Roots, Northey (Northey or "Claw"), which are typically used in vacuum applications. , And snail doubt pump. The present invention is directed to the improvement of the operation of the above pumps. [Previous technology] Shipu pumps are widely used in industrial processes to provide product manufacturing, and / or low-pressure royal clothing. Applications include pharmaceutical and semiconductor manufacturing. ”$ &Amp; kind of help / • Includes a main dry (or oil-free) help pumping mechanism, but each book also includes several components such as bearings and transmission gears to drive the help Pumping mechanism and also need lubrication for efficiency. Dry pumps incorporating Luoci and / or Northrop-type mechanisms are usually multi-stage positive displacement pumps' using two mutually shouting rotors in each vacuum chamber. The two rotors may have the same shape in each room, or each room may have a different shape. 0 The spiral type ㈣ mechanism of the Xing type includes two parallel ㈣ light units, each containing an externally threaded rotor, and two shaft rod systems. Make the threads of the two rotors mutually intertwined with each other. Between the two threads at each point of engagement, the parent and the thread and the pump body (tolerance of a function, so that the tight capacity of the human gas capacity: = is captured between the two rotor threads, between the inner surfaces', thus When the two rotors rotate, the basic screw pump mechanism has been known in various modifications = ': a screw pump already exists' which has a thread and / or machine with a pitch change " The height (or outer diameter) of the rotor is tapered in the direction from the mouth of the pump H. 97335.doc 200521330 f. In the latter case, the two rotors are tapered on the stator. In the inner cavity, when Tian Shizuo's dry pump reaches the required pressure ("final force") which is extremely lower than atmospheric pressure, it is better that the power required to operate the pump has been reduced to a minimum. Degree. The size of the pump discharge capacity has a considerable influence on the input power required for the operation-pump under the final dust force. The high volume of the exit volume by the built-in pump-inlet volume Ratio, the input power can be kept very low in the final Baoli The disadvantage of the ㈣ arrangement is that when the inlet pressure of the pump is increased to atmospheric pressure, the input power requirement of the pump will increase significantly. In the previous technology, the internal pressure of the high pump has been waived. Add a blow-off valve to α 卩 in Gang 4; the blow-off valve can be activated to relieve pressure and prevent excessive pressure increase in the pump. In some cases, the performance of these valves may be accumulated on the sealing surface The adverse effect of or near the processing medium reduces the efficiency of pressure enhancement to release. [Summary of the Invention] According to one aspect of the present invention, a dry pump is provided, including a stator. The first and the first rotors which are engaged with each other and rotate in opposite directions, the pump also includes a mechanism for causing the two rotors to move axially in the stator, and when the mine is installed in the gang, it is used to change at least one between the two rotors And the stator. For example, under the immediate response to the internal operating conditions of the pump, actively controlling the axial position of the two rotors in the stator can make one between the two rotors and the stator The clearance can be increased or decreased as required in the use of the pump. 97335.doc 200521330 or maintained at a constant level. For example, when the dusty or dusty atmosphere is closed afterwards, the two rotors are fixed. = Question :: Π 'even maximized' to prevent asking during restart = 2 lives. In operation, the axial gap between the mule and U may = process the sediment 'and when the pump stops, the rotor It will cool down and shrink the deposits, which may lock the pump. When the pump is stopped, moving the rotor relative to the stator can increase the axial clearance and thus the probability of a new start. The axial gap immediately drops back to the normal running gap in the pump operation. The interval can be actively replaced by the deposition replacement or additional method. The two rotors move near the surface of the stator during the pump life to scrape and accumulate on the stator. Surface object 0 The clearance of the rotor can also be controlled for different pumping gas types to improve the performance of pumping. For example, when pumping hydrogen or an inert gas such as argon, the fH gap can be increased or decreased to achieve the best performance of the work, so that no pump stuck. The chirping of the two rotors in the stator can significantly reduce various operating variables, such as the impact of back pressure, operating temperature, and gas type, on the performance of the pump. In addition, the ability to actively control the position of the rotor can loosen the manufacturing accuracy of each component. This results in a significant reduction in costs, as it eliminates the need for grinding operations and reduces the level of scratching. For example, in one embodiment, the pump includes means for causing the rotor to move axially during its operation in response to the axial load generated by the two rotors. When in operation, the internal pressure of the pump generates a shaft 97335.doc 200521330 two thrust loads on the rotor, which is proportional to the gas [shrinking work] being performed by the pump, and therefore also proportional to the pump The input power requirement is directly proportional. For example, the gas compression efficiency of a helical pump is greatly controlled by the "inside surface of the stator of the clothes-loaded screw rotor, and the gap between the two rotors themselves." Where the two rotors are tapered, the rotors can move away from the stator surface simultaneously and simultaneously, effectively increasing the radial clearance, reducing the compression effect, and thus reducing the requirements for power input. The same Roots rotor, which can also gradually grow, can move away from the stator surface simultaneously and simultaneously, effectively increasing the radial clearance, reducing the compression effect, and thus reducing the requirements for power input. Each rotor is typically installed on an individual shaft (or integrated with it), and the shaft is rotatably installed in the pump. The pump includes a bearing assembly 'for Chengke Relative shaft rotation supports two shafts. In a preferred embodiment, the arrangement for causing the two rotors to move axially in the stator is constituted by a device for moving the bearing assembly relative to the stator. In a specific embodiment, the The bearing assembly can be free in the housing with a σ ## movement. The device for causing the two rotors to move axially includes a mechanism that is configured relative to a rotor so that the rotor can withstand a shaft. When the load is directed, the spring mechanism will contract or stretch, causing an axial reaction load. When an -axial load is generated on the -rotor, and there is a tendency to induce axial displacement of the rotor and the drawing assembly, the spring can be invited to contract or expand (depending on its position). Assuming the load does not exceed the spring's elastic limit, the spring will react to change the axial position of the rotor. By choice—a spring with the appropriate impulse constant 97335.doc 200521330, this arrangement can be used to change the gap between the rotor and the stator, to give a relatively constant level of gas compression work over a wide inlet pressure range, thereby slowing down Requirements for pump power input. In other embodiments, the pump includes a control device for actively controlling the operation of the device that causes the two rotors to move axially. For example, a piston or other actuator may be provided specifically for moving the rotor, and the control device controls the movement of the actuator to control the axial position of the two rotors. In a preferred embodiment, the control device controls a motor adapted to rotate a drive shaft, which is connected to the actuator so that the actuator can be moved relative to the stator in the axial direction by the rotation of the drive shaft . The drive shaft may, for example, include a $ screw cup that is passed through a matching threaded aperture on the actuator. Alternatively, the control device may be composed of one or more electromagnets to move the actuator. Any other convenient mechanism for accurately moving the two rotors relative to the stator may be provided. For example, a piezoelectric actuator may be provided, which may be deformed in response to a voltage supplied from the control device to the actuator. Alternatively, a metal ring, tube, or other element may be provided, and selective heating is given by the control device, so that the thermal expansion at the end of the element causes the two rotors to move within the stator. The most appropriate mechanism can be selected for the degree of movement of the two rotors relative to the stator. For example, 'for a Nose type rotor, the maximum required movement amount may be less than 100 micrometers', and for a tapered spiral rotor, the required movement amount may be about 1 mm. Where the movement of the two rotors is caused by the movement of the bearing assembly relative to the stator, the actuator can expediently include part of the bearing assembly housing, or be carried by the 97335.doc -10- 200521330 office. The bearing assembly housing preferably includes an inner sealing mechanism for the pump. This bearing assembly, preferably, supports one end 'of each shaft to provide a second bearing assembly to support the other end of each shaft. This bearing assembly can be fixed with respect to the stator or arranged so that it can move with the shaft =. The housing of the latter second bearing assembly may also contain a seal mechanism. This will ensure that the movement of the shaft relative to the stator will not damage the inner pump seal. One or both of the housings of the two bearing assemblies may define the end surface of the stator so that when the axial position of the two rotors is slapped, the slug surface moves together with the two slats, thereby borrowing between the two rotors. Maintaining a constant gap between the end of the stator and the end surface of the stator can prevent a collision between the ends of the two rotors and the end surface of the stator. The control device may be configured to be adapted to receive a signal indicative of Xupu operating parameters, and to be adapted to control the axial position of the two rotors by means of the one signal. The operating parameters may include-among the temperature of the stator and / or inside the stator, the final vacuum calibration at startup, back pressure, exhaust temperature, power consumption, and inlet pressure. With regard to temperature, the failure of the cooling water is likely to cause a problem that the thermal shock will distort the stator to such an extent that the rotor and the stator are in contact. It is possible to detect the start of a stuck condition by measuring the sub-temperature and the inlet water temperature, and to increase the gap between the rotor and the fixed period when the thermal shock occurs, to help the pump. High back pressure can lead to an increase in the internal gas temperature and a difference from the rotor to the stator, which may cause the pump to bite. By measuring the gas temperature inside the volume 冽, the gap between the rotor and the stator can be changed to mitigate the increase in back pressure. In terms of power consumption, the control device can be configured to receive a signal indicating the power consumption of a motor used to rotate one of these rotors, and to control the actuation of the actuator in response to the signal. signal. Alternatively, or in addition, the control device may include a sensor for measuring a gap size or a rate of change between the meson and the rotor and the control device is configured to control a An output from a sensor that induces axial movement of the rotor. The sensor can be conveniently provided as a HaU effect sensor. The sensor can be pre-calibrated by determining the position of the rotor when the pump has zero axial clearance. This can be achieved by moving the rotor axially until contact occurs when the pump has been warmed up before Lipu is used to cause thermal effects (these rotors are not rotating). Alternatively, these thermal effects are built into the control device so that when determining the size of an axial gap based on the signal output from the sensor; these thermal effects are taken into account. The device for causing the rotor to move axially is preferably configured to ensure that both rotors are maintained at the same axial position, but may also be configured to allow relative axial movement between the two rotors. Typically, this relative movement will be within the two limits of rotor contact, and it can be used with the two rotors to scrape off the processing medium accumulated on the sides of the two rotors, or it can be fine-tuned at regular intervals. The relative movement between the two rotors can be achieved by using an independent device that can be used to induce the axial movement of each rotor, such as the aforementioned separate actuator settings. An associated control device may be configured to cause the two rotors to move independently of each other. This can be achieved by monitoring the reach of one rotor when the two rotors are stationary, or by monitoring shaft torque or motor current when both rotors are running at full speed. 97335.doc -12- 200521330 In the case where the two rotors have interlocking lines, at least part of the threads, preferably with -external straight line! , It has a tapered shape in the direction from the m σ _ exit of the pump. In a specific embodiment, each thread has—a decreasing straight from the pump population to the exit. In another—a specific embodiment, only a portion of the threads of each rotor has an outer diameter that gradually decreases toward the pump outlet. , The rest of the thread has a generally constant outer diameter. There are many advantages associated with the latter specific embodiment described above. First, the temperature of the exhaust gas of the vacuum pump varies with the operating conditions and will affect the gap between the rotor and the stator at the exhaust (low vacuum) end of the pump. During the exhaust phase, the performance of the rotor can be allowed to be optimized. The inlet (high vacuum) temperature does not change as significantly as the outlet, and therefore rotor-to-stator control during the inlet phase is less important. Secondly, during heavy operation (because a large amount of gas is pumped at or near atmospheric pressure), performance can be optimized by avoiding the low vacuum stage of the pump. The rotor-to-stator clearance during the exhaust phase can be increased to act as the same pressure valve, while the rotor-to-stator clearance dimension during the population phase is often constant to maximize pumping efficiency. When the two rotors are (at least partially) tapered, the size of the radial gap between the rotor and the stator can be determined by the size of the axial gap between the rotor and the stator. The relationship between axial clearance and radial clearance can be established during testing. The two rotors can pulsate between two axial positions to remove process deposits in the axial gap between the rotor and the stator. For example, the control device may be configured to move the two rotors in an axial direction at a first speed to increase the axial clearance between the rotor and the stator, which is different from the first speed of 97335.doc -13 · 200521330 Move the two rotors' to reduce the axial gap between the rotor and the stator ..... P-stops the tripping of the pump motor. The reduction rate of the axial gap is relatively greater than the increase rate of the axial gap. A linear decoder can be prepared in case: the two rotors are stuck at the extreme ends of the axial position. In a second aspect, the present invention provides a method for controlling the operation of the pump: the pump includes a certain son, which is equipped with a brother suitable for the opposite doubt in the stator, and a second mutual Engage the rotor; the method includes the steps of: when the two rotors are stationary, moving the two rotors axially relative to the stator to increase the axial clearance between the two rotors and the stator; subsequently starting the rotor to rotate; and during the rotation of the rotor ' The two rotors are moved axially relative to the stator to reduce the axial gap between the two rotors and the stator. "It still includes the step of successively (preferably repeated) during the use of the pump, a step of reducing the axial gap by one, so as to move the sediment away from the axial gap. In the third aspect of the present invention In the present invention, a method for controlling a group of Pu Hongzhuo is provided. The pump includes a stator, which is provided with a first _ ^ I _ = soil & β spear first interengaging rotor suitable for reverse rotation in the stator; The method includes the steps of continuously moving the two rotors relative to the stator in the axial direction of the phase to periodically change the axial gap between the two rotors and the stator, and to move the deposit away from the axial gap. The characteristics of the first aspect of the present invention stated by Jin Jin are equally applicable to the method aspect of the invention; otherwise, it is correct. The specific embodiment of the right-hand stem of the native month will be explained by way of example and further with reference to the following drawings. [Embodiment] Referring to FIGS. 1 to 4, ^ ^ 1 η ^ pump 10 includes a pump body 12 having a pumping chamber 18 defining a portion 14 and a second portion 16 of 97335.doc -14-200521330. A fluid inlet 20 leading to the chamber 18 is made in the first part 14 of the pump body 12, and a fluid outlet 22 from the chamber 18 is made in the first part 16 of the pump body 12. The pump 10 further includes a first shaft 24 and a second shaft 26 spaced from the first shaft and arranged in parallel. Both bearings 28 are provided to support the shafts 24,26. The shafts 24, 26 are adapted to rotate in opposite directions about their respective longitudinal axes. One of the two shafts 24 is connected to a drive motor 30 via a driving mechanism 32; the two shafts are connected by a timing gear so that in use, the two shafts 24, 26 are at the same speed, but at Rotate in the opposite direction. A first rotor 34 is mounted on the first shaft 24 for rotational movement in the cavity 18, and a second rotor 36 is mounted on the second shaft 26 for the same purpose. The two rotors 34, 36 each have a gradually tapered shape, and have propellers or threads 38, 40, which are respectively made on the outer surfaces of the two rotors, and the two threads are mutually as shown in the figure. Toothed. In this specific embodiment, the threads 38, 40 of the two rotors 34, 36 each have an outer diameter, and are reduced in a tapered shape in the direction from the pump 10 inlet 20 to the outlet 22, and the pumping The cavity 18, which is used as a stator in the use of the pump, gradually becomes smaller toward the pump outlet 22 in accordance with the requirements. The shapes of the two rotors 34, 36, especially the shapes of the threads 38, 40 opposite each other and the pumping chamber u, are planned to ensure a close tolerance with the inner surface of the pumping chamber 18. ~ In order to control the axial position of the two rotors 34, 36 in the pumping chamber 18, the pump 10 includes two bearing assemblies 42, each of which is slidably installed on its own, located at the discharge end of the pump 10. The cylindrical housing 44 is shown in more detail as shown in FIGS. 5 to 7 at 97335.doc -15-200521330. The cylindrical housings 44 are fastened to the respective shafts 24, 26, and the two round cymbal-shaped housings 44 are connected to each other by a connecting arm 牝. Each bearing assembly 42 is composed of a double angular surface contact bearing 48, and the two latter are arranged in a back-to-back configuration to maintain the lateral position of the shaft 24 passing through the bearing assembly 42 relative to the pump body 12, but The shaft can be allowed to move axially and rotate about its longitudinal axis. A small gap is provided between the outer surface of the bearing 48 and the inner surface of the cylindrical housing 44. There is also a small axial gap between the cylindrical housing 44 and the pump body 12. This gap allows the initial gap to be clamped between the pump body and each cylindrical housing 44 during the pump assembly process. A thin sheet of material is placed between the flanges 50 and can be fixed. Sitting between the bearing 48 and the end wall 52 of the cylindrical housing 44 is a space 54 and a spring 56. The bearing 48 is retained in the casing 44 by a clamping ring 58 so that a preset load suitable for the operating load condition (and the input power of the pump) is set on the elastic yellow 56. The end wall 52 is radially inwardly extended toward a shaft 60, and the collar 60 is formed as a part of a fastening assembly that fastens the cylindrical housing 44 to the shaft. In use, the compression work performed by the pump 〇0 results in a load which is inclined to move the sleeves of the two rotors 34, 36 in the direction from π 22 to the population 2G. This axial load acts tightly against the spring 56 to cause the two rotors 34, 36 to move in the axial direction f, thereby changing between the threads 38, 40 of the two rotors 34, 36 and the stator in proportion to the axial load. Radial clearance. By changing the characteristic elasticity rate, the input power can be tailored to suit the pump speed range—specially using it. There is any difference in the axial load of the two rotors 34 and 36. The connecting rod that firmly connects the two cylindrical shells 44 together 97335.doc -16-200521330 46 can ensure that the two rotors are repositioned at the same time. When one or two rotors become incorrectly aligned relative to each other, any interference that may occur between the two threads 38, 40 of the rotor μ,% can be avoided. In a variation of the specific embodiment shown in Figs. 1 to 7, the axial position of the two rotors is controlled by a pneumatically controlled piston. The movement of the piston can be controlled by a control mechanism. The control mechanism may include a pressure sensor that can detect an axial load on a given rotor axis and can cause a reaction force exerted by the piston. In addition, the controller can be pre-configured to allow independent movement of the piston, thus allowing the two rotors to be used in other specific embodiments shown in Fig. 8-Spiral Pump, with two positions of the rotor in the stator. Ability. Similar to the first embodiment, the pump includes a pump body 72 defining a pumping chamber 74, a fluid inlet%: and a fluid outlet 78. The pump 70 further includes a first shaft rib and a second shaft 82 arranged parallel to and spaced from the first shaft. The first bearing assembly is provided to support the upper ends of the two shafts 80 and 82 (as shown in FIG. 8 and the second bearing assembly inside the bearing housing 88 is provided to support the lower ends of the two shafts such as Prepared. The two shafts 80 and 82 are adapted to rotate in the opposite direction of rotation in the caster box M inner ring cast longitudinal axis. One of the two shafts—the second drive mechanism is connected to a drive motor (not shown), The two shafts are connected by _ = window wheel 90, so that in use, the two shafts 80, 82 rotate at the same speed but in opposite directions. ° A first rotor 92 is for the cavity Rotating motion in 74 while two shafts and one second rotor 36 are installed for the same purpose: two rotors 92, 94 are each present-a population with a large shape 76 turns 97335.doc -17- 200521330 has a cent, And there is a second part in the vicinity of the outlet 78 with a tapered shape. Each rotor has a propeller or a thread%, 98, respectively made on its outer surface, and the two threads are intermeshing as shown in the figure. Threads 96 and 98 of 92 and 94 have a substantially constant outer diameter on the first part of each rotor The second part of each rotor has an outer diameter that gradually decreases toward the direction of the outlet 70 of the pump 70. The inner surface of the pumping chamber 74, which is used in the pump + acts like a certain child, is in line with The outer diameter shape of the two rotors is made. In order to control the axial position of the two rotors 92 and 94 in the pumping chamber 74, the pump 74 includes a servo motor 100 and rotates a guide attached to the motor Screw 102. The lead screw 102 is engaged with an aperture 104 with a corresponding thread formed on the bearing housing 88, so that the bearing housing 88 acts as a same piston and moves axially relative to the pumping chamber 74. In order to control the gap between the rotor and the stator on the pump 70, the actuation of the servo motor 100 can be controlled by any suitable mechanism. For example, a sensor 106 (such as a Hall effect Provide the signal of the motor 100, or (as shown in the example figure) a separate motor controller 108—indicating the size of the axial gap between the two rotors and the stator # or the rate of change); the operation of the motor 100, It is controlled based on the signal received from the sensor 106. The motor is moved in the axial direction as needed to increase or decrease the amount of axial clearance. In this second specific embodiment, the mechanism for axially moving the rotor relative to the stator is, of course, capable of being used to move a thread having all of a tapered shape The rotor is the same as that used in the first embodiment. In the third embodiment shown in FIG. 9, this mechanism is used to axially move 97335.doc -18- 200521330 Rotor 110 'and therefore the axial clearance between rotor 11 () and the end surfaces 116, 118 of stator 114' can be used, for example, to scrape off the treatment at both ends of the stator / 1 'and prevent restarting Of failure. In this specific embodiment, 'the fixed bearing assembly 84 has been replaced by a floating bearing assembly, where two bearings are arranged in a bearing housing 120, and the latter is axially moved with the axial movement of the rotor mobile. The tight tolerance between the outer wall 122 of the bearing body 120 and the two walls 124 of the gear box 83 is used to control the radial position of the bearing housing 120. The outer wall 122 of the bearing housing 120 A fluid seal mechanism (not shown) is provided to prevent oil from entering the pumping chamber 126 from the gear box 83. A similar sealing mechanism (not shown) is carried in the bearing assembly's casing to seal the pumping chamber 126. In the specific embodiment of FIG. 10, the threaded rotor 110 has been replaced with a Nose-type rotor 130 to provide a multi-stage positive displacement pump. By the axial movement of the rotor, the control lies on the surfaces of the two rotors 130 and the opposite stator 132. Gap between surfaces. FIG. 11 shows a dry pump with a roots-type rotor 140. The Roots-type rotor 140, similar to the thread in the first embodiment, gradually becomes smaller in the direction from the inlet to the outlet of the pump; the inner surface of the stator 142 gradually becomes smaller toward the outlet of the pump. In this specific embodiment, the axial movement of the rotor i40 controls the radial gap between the rotor 140 and the stator 142. In this example, the axial gap between the ends of the two rotors and the end surfaces 144 and 146 of the pumping chamber accommodating the two rotors is maintained by the axial movement of the two rotors with respect to the stator 142. Roughly constant. As shown in the figure, the two end surfaces 144 and 146 are defined by the housings supporting the ends of the shafts 80 and 82 97335.doc -19- 200521330 146 as the two rotors 14 move 88 and 120, Therefore, the surfaces of both ends are moved. In Figures 8 to U, the mechanism for moving the rotor relative to the stator in the axial direction is fixed at the low pressure (inlet) end of the pump. However, this mechanism can be replaced with the high pressure (outlet) end of the pump. In addition, although in the specific embodiments shown in Figs. 8 to U, the axial clearance is monitored by the sensor 106, other operating parameters of the pump, such as back pressure, discharge temperature, power consumption, and / or inlet The pressure can be transferred to the controller 108 or directly transmitted to the motor 100 for controlling the axial position of the rotor in the use of the pump 70. This signal can be output from a suitably positioned sensor; where appropriate, or from a motor that drives the rotor to rotate. In addition to controlling the axial position of the rotor in response to signals output from these sensors, other operating parameters can also be adjusted in response to these signals. For example, the temperature and / or flow rate of the cooling water supplied to a cooling jacket or other heat transfer device extending around the stator can be adjusted according to the size of the gap so that the stator can keep up with the expansion and contraction of the rotor. In step, comprehensively, _, currently provides a dry pump, which includes a stator, which contains the first and second interlocking rotors, is adapted to rotate in the stator in the opposite direction, and is used in pumps. Actively control the axial position of the rotor in the stator. [Schematic description] Figure 1 is a side view of a first embodiment of a spiral pump; Figure 2 is a plan view of the pump in Figure 1; Figure 3 shows a section through the plane bb in Figure 1; 97335. doc -20- 200521330 Figure 4 shows a section through the plane A_A in Figure 2; 05 is a plan view of the device that causes the two rotors in the pump to move axially; Figure 6 shows a section through the plane a_a in Figure 5. Fig. 7 is a perspective view of a device for causing axial movement of the two rotors in the pump; Fig. 8 shows a cross-section of a second specific embodiment of the spiral pump; Fig. 9 shows a third specific embodiment of the spiral pump Fig. 10 shows a section through a Northey pump embodiment; Fig. 11 shows a section through a Roots pump embodiment. [Description of main component symbols] 10, 70 pump 12, 72 pump body 14 first part 16 second part 18, 74, 126 pumping chamber 20, 76 fluid inlet 22, 78 fluid outlet 24, 26, 80, 82 shaft 28 bearing 30 drive motor 32 drive mechanism 34 > • 36, > 92, 94, 110 rotor 38, _40, '96 ~ 98 thread 42, 84 > -86 bearing assembly 97335.doc- 21-200521330 44 46 48 50 52 54 56 60 83 88, 120 90 100 102 104 106 108 112 114, 132, 142 116, 118, 144 122 124 130 140 d Cylindrical housing connecting arm or connecting rod angular surface contact bearing Clamping flange end wall spacer ring spring collar gear box bearing housing timing gear servo motor lead screw aperture sensor controller non-tapered thread stator 146 end surface outer wall wall Nose type rotor Roots type rotor shaft Toward gap size 97335.doc -22-