Pumping device for sucking or draining fluid

A pumping device, comprising:

• a seal cap unit including:
• a cap;
• an air relief member connected with the cap;
• and
• a regulating member removably connected with the air relief member;
• wherein:
• the cap of the seal cap unit has a first end provided with an air inlet hole and a second end provided with an air outlet hole;
• the air outlet hole of the cap has a periphery provided with a through hole;
• the through hole of the cap is extended through a bottom of the cap;
• the air relief member has a first end mounted in the air outlet hole of the cap and a second end protruding outward from the air outlet hole of the cap;
• the air relief member has an interior provided with a guide hole;
• the guide hole of the air relief member has a periphery provided with a plurality of apertures;
• the apertures of the air relief member are arranged in a radiating manner;
• the regulating member of the seal cap unit is an integral structure;
• the regulating member of the seal cap unit is screwed onto the second end of the air relief member;
• the regulating member of the seal cap unit has a central position provided with an air relief hole connected to the guide hole of the air relief member;
• the regulating member of the seal cap unit has a periphery provided with a plurality of draining holes to introduce and drain air in the regulating member;
• each of draining holes has a diameter greater than that of the air relief hole;
• the guide hole of the air relief member has a front end provided with a tapered groove;
• the regulating member has an inner side provided with a tapered projection located between the air relief hole and the draining holes;
• when the regulating member is mounted on the second end of the air relief member, the air relief hole is aligned with and connected to the guide hole of the air relief member;
• when the regulating member is locked onto the second end of the air relief member, the tapered projection of the regulating member extends into and closely presses the tapered groove of the air relief member;
• and
• when the tapered projection of the regulating member presses the tapered groove of the air relief member, the draining holes of the regulating member are closed by the air relief member, and the air relief hole of the regulating member is open and connected to the guide hole of the air relief member.