each other and defining a plurality of chambers therein the air chamber cover and the air chamber box are provided with air guide tubes recesses air holes co operating with catch plates so as to increase the path of the air flow thereby reducing the velocity of the air flow so as to eliminate the noise application_number US 61927300 A description referring to the drawings and initially to fig2 5 a sound elimination structure in accordance with the present invention is used for an air pump 20 which comprises a body 21 a compression cup 22 a vibration crank 23 and two anti reverse structures 24 the body 21 is separated into an air inlet chamber 211 and an air outlet chamber 212 and has a first side provided with a washer 215 and a cover plate 216 and a second side provided with a flange 25 the air inlet chamber 211 is provided with an air input hole 2111 and an air inlet hole 213 the air outlet chamber 212 is provided with an air output hole 2121 and an air outlet hole 214 the vibration crank 23 has a first side secured on the compression cup 22 which is mounted on the lug 25 and a second side provided with a magnet 231 co operating with an external electromagnetic device not shown each of the air input hole 2111 and the air output hole 2121 defines a recess not shown for receiving an anti reverse structure 24 the body 21 is provided with a.