Patent Application
20080115843
The present invention relates to negative pressure check valve, and particularly to a negative check valve of a pneumatic transfer pipe which is widely used in the oil saving/water system of fuel pipes of vehicles and transferring pipes of water and chemical liquids.
A prior art check valve has a steel ball and a spring. Positive pressure is used to shift the steel ball so as to opening the valve for providing air or liquid. When the positive pressure is disappear, the steel ball moves and the spring extends so that the steel ball returns to the original position to close the check valve.
However this prior art design is not suitable for negative pressures. Thus o until now, no negative pressure check valve is provided.
However in many current applications, such as oil or water saving pipes by using Venturi tubes, the negative pressure check valve is required in conditions so as to have preferred effects.
Accordingly, the primary object of the present invention is to provide a negative check valve of a pneumatic transfer pipe, which is widely in used the oil saving/water system of fuel pipes of vehicles and transferring pipes of water and chemical liquids.
To achieve above objects, the present invention provides a negative check valve of a pneumatic transfer pipe which comprises a casing having a hollow chamber and a channel which is communicated to the hollow chamber; a cover having a penetrating channel; a plug movably received in the hollow chamber of the casing; a washer installed between the casing and the cover; an center of the washer having an opening which can be sealed by the plug; wherein when a positive pressure is applied to the plug, the plug will be pushed upwards by floating force and the pressure so that seal the opening of the washer to isolate the opening; when a negative pressure is applied to the plug by suction force of vacuum, the plug will descend to the bottom of the hollow chamber so that the opening is opened and gas or liquid flows through the washer.
The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing.
In order that those skilled in the art can further understand the present invention, a description will be provided in the following in details. However, these descriptions and the appended drawings are only used to cause those skilled in the art to understand the objects, features, and characteristics of the present invention, but not to be used to confine the scope and spirit of the present invention defined in the appended claims.
The negative check valve of a pneumatic transfer pipe of the present invention is widely used in the oil saving/water system of fuel pipes of vehicles and transferring pipes of water and chemical liquids.
Referring to
A casing 1 has a hollow chamber 11 and a channel 10 which is communicated to the hollow chamber 11. The casing 1 has a joint 12 with outer thread 121 for engaging with other pipes or a Venturi tube n (referring to
A cover 2 has a penetrating channel 20 and a joint 21 with outer thread 211 for engaging with another pipe or gas/liquid filter 6.
A plug 3 is movably received in the hollow chamber 11 of the casing 1. A bottom of the plug 3 has a concave or plan bottom.
A washer 4 is installed between the casing 1 and the cover 2. A center of the washer 4 has an opening 41 which can be sealed by the plug 3.
Referring to
The present invention is thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
