A suction pump unit comprises a vacuum port, an excess pressure port and a switching valve (2). The switching valve (2, 9) comprises a valve body with two inputs (22, 23), wherein a first of the inputs (22) is connected with the vacuum port, and a second of the inputs (23) is connected with the excess pressure port. The switching valve (2) further comprises an output (26) with a through hole, wherein the output (26) can be moved relative to the inputs (22, 23) from the first input (22) to the second input (23) and back, as a result of which the through hole alternately establishes a fluid-communicating connection with one of the inputs (22, 23). The through hole of the output (26) is released and ventilated during at least part of the movement between the two inputs (22, 23). This suction pump unit permits passive and active ventilation of an output line (4) connected with the output (26).一吸入泵單元包括一真空埠、一過壓埠及一切換閥(2)。該切換閥(2、9)包括一具有二輸入件(22、23)之閥體，其中，該等輸入件之一第一輸入件(22)與該真空埠連接，及該等輸入件之一第二輸入件(23)與該過壓埠連接。該切換閥(2)進一步包括一具有一通孔之輸出件(26)，其中，該輸出件(26)可相對該等輸入件(22、23)從該第一輸入件(22)移動至該第二輸入件(23)及返回，其結果為該通孔輪流和該等輸入件(22、23)之一建立一流體連通式連接。該輸出件(26)之該通孔在移動於該二輸入件(22、23)之間的至少部分期間被鬆脫開及通氣。此吸入泵單元使和該輸出件(26)連接之一輸出管線(4)可有被動式及主動式通氣。
