BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded view of the present invention;
FIG. 2 is a side cross-sectional view of the present invention;
FIG. 3 is a bottom view of a base of the present invention;
FIG. 4 is a side cross-sectional view of the present invention showing a removable cover in an operating status;
FIG. 5 is a side cross-sectional view of the present invention showing air flown into the tank; and
FIG. 6 is a side cross-sectional view of the present invention showing air flown away from the tank.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
As shown in FIG. 1, a preferred embodiment of the present invention comprises a base 1, a cap 2 and a cap seat 3.
The base 1 comprises a through hole 11, a first engaging section 12, and a second engaging section 13 at the top and the bottom of the base 1. The base 1 has an air inlet passage 14 at one end and an air outlet passage 15 at the opposite end of the air inlet passage 14. The air inlet passage 14 has an air inlet hole 141 in a smaller diameter at the top of the base 1, and the air outlet passage 15 has an air outlet hole 151 in a smaller diameter at the bottom of the base 1. The air inlet passage 14 is provided with an air washer 142, a locating sleeve 143, a spring 144, and a block 145 in sequence. The air outlet passage 15 is provided with an air washer 152, a locating sleeve 153, a spring 154, and a block 155 in sequence. The locating sleeve 143 has a hole 146 for the air washer 142 to seat therein. The locating sleeve 153 has a hole 156 for the air washer 152 to seat therein. One end of the spring 144 engages with the air washer 142 while the other end of the spring 144 engages with the block 145. One end of the spring 154 engages with the air washer 152 while the other end of the spring 154 engages with the block 155. The block 145 has a through hole 147. The block 155 has a through hole 157. As shown in FIGS. 1 and 3, the base 1 further comprises channels 16 and 17 interconnecting with the air inlet hole 141 and the air outlet hole 151 of the air inlet passage 14 and the air outlet passage 15, respectively.
The cap 2 comprises a third engaging section 21 at the bottom thereof to be engaged with the first engaging section 12 of the base 1. An opening 22 is formed in the center of the cap 2.
The cap seat 3 comprises a fourth engaging section 31 at the top thereof to be engaged with the second engaging section 12 of the base 1. A removable cover 32 is pivotally connected to the cap seat 3.
To pump gasoline into a tank incorporated with the present invention, as shown in FIG. 4, the pump gun is inserted into the tank through the opening 22 of the cap 2 and the through hole 11 of the base 1. The gun will push the removable cover 32 of the cap seat 3 away for the gun to be inserted direct into the tank. Should the atmosphere pressure is bigger then the pressure in the tank, as shown in FIG. 5, the tank will have a sucking force which moves the air washer 142 in the air inlet passage 14 away from the air inlet hole 141 to depress the spring 144, thus outside air is able to flow through the channel 16, the air inlet hole 141, the air inlet passage 14, the through hole 147 of the block 145, and the channel 17 in sequence into the tank. The air pressure between the tank and the atmosphere will reach a balanced situation.
When the pressure in the tank is bigger than the atmosphere, as shown in FIG. 6, the tank will have a push force which moves the air washer 152 in the air outlet passage 15 away from the air outlet hole 151 to depress the spring 154, thus the air in the tank may be flown through the channel 16, the air outlet passage 15, the through hole 157 of the block 155, and the channel 17 outward, balancing the pressure in and out of the tank.