the following paragraphs will illustrate the present invention in more detail with preferred embodiments . referring to fig1 and 2 , the air compressor equipment of the present invention generally comprises a supportive box 1 and a sealant dispensing unit 9 . the supportive box 1 is substantially rectangular in shape , in which a compressor unit ( not shown ) being able to generate high - pressure air is provided . the supportive box 1 is provided on its outer surface with a switch 10 that can start and stop the compressor unit . the supportive box 1 defines a positioning slot 15 , which is a recessed space . the sealant dispensing unit 9 can be inserted into the positioning slot 15 , so that it can be positioned stably and will not tilt or tip over . a first hose 17 has one end being connected to an outlet of the compressor unit ( which is related to prior - art technology and not shown in the figures ) and has the other end being connected to a first hose connector 37 of the sealant dispensing unit 9 . a second hose 18 has one end being connected to a second hose connector 38 of the sealant dispensing unit 9 and has the other end being connected to an air nozzle 191 of a tire 19 . when the switch 10 is switched on , the high - pressure air generated by the compressor unit can go through the first hose 17 , the interior of the sealant dispensing unit 9 , and the second hose 18 to enter the tire 19 , thereby inflating the tire 19 or delivering the chemical sealant 26 to repair the tire 19 as well as inflating the tire 19 . referring to fig2 through 5 , the sealant dispensing unit 9 generally includes a bottle 2 , a cap 3 , and a tube 5 . the bottle 2 has a top opening 21 and a bottom 27 . the bottle 2 defines therein an inner space 22 for storing the chemical sealant 26 ( see fig6 and 7 ). the bottle 2 is provided with engagement seats 23 , 24 , 25 respectively at its two sides and bottom . the cap 3 can be combined with the top opening 21 of the bottle 2 by thread engagement or thermal bonding . in this embodiment , the cap 3 is connected to the bottle 2 by thermal - bonding the cap flange 31 of the cap 3 with the top opening 21 of the bottle 2 . the cap 3 has a lower cylindrical pipe 32 extending downwardly and an upper cylindrical pipe 36 extending upwardly , wherein the lower cylindrical pipe 32 communicates with the upper cylindrical pipe 36 . the lower cylindrical pipe 32 defines multiple slots 34 around its periphery . the lower cylindrical pipe 32 is provided at its bottom with a circular bottom wall 33 that extends inwardly along a radial direction of the pipe 32 , wherein the circular bottom wall 33 defines a central circular opening 331 communicating the inner passage 35 of the lower cylindrical pipe 32 ( see fig4 and 5 ). the upper cylindrical upper pipe 36 has a top opening 39 and defines two opposite mounting slots 392 , each of which is open in its top and closed in its bottom . also , the upper cylindrical pipe 36 defines two opposite pin holes 391 adjacent to the two mounting slots 392 . also , the upper cylindrical pipe 36 is provided with the first hose connector 37 and the second hose connector 38 , both of which communicates with the inner passage 393 of the upper cylindrical pipe 36 . the sealant dispensing unit 9 further includes a spring 6 , which is inserted through the top opening 39 of the upper cylindrical pipe 36 and placed on the circular bottom wall 33 at the bottom of the inner passage 35 of the lower cylindrical pipe 32 . the sealant dispensing unit 9 further includes a tube 5 with a predetermined length and an inner passage 50 . the tube 5 generally has a top segment 51 and a bottom segment 59 , wherein the top segment 51 is provided with a closed top face 510 and a bottom seal ring 511 , and the bottom segment 59 defines a bottom opening 590 . the top segment 51 has a greater diameter than the bottom segment 59 . the bottom segment 59 defines multiple notches 591 around its bottom periphery . furthermore , the tube 5 is provided with two upper , spaced - apart , annular protrusions 52 and two lower , spaced - apart , annular protrusions 56 between the top segment 51 and the bottom segment 59 , wherein the upper and lower annular protrusions 52 , 56 have a greater diameter than the bottom segment 59 of the tube 5 . between the segment 51 and the upper annular protrusions 52 defines a first annular slot 55 which has a smaller diameter than the bottom segment 59 of the tube 5 . the tube 5 defines at the first annular slot 55 a through hole 550 by which the inner passage 50 of the tube 5 communicates with the first annular slot 550 . between the upper annular protrusions 52 and the lower annular protrusions 56 defines a second annular slot 58 which has a smaller diameter than the bottom segment 59 of the tube 5 . between the two upper annular protrusions 56 is provided with a first seal ring 53 . between the two lower annular protrusions 56 is provided with a second seal ring 57 . the bottom segment 59 of the tube 5 is inserted to go through the top opening 39 of the upper cylindrical pipe 36 and go out of the central circular opening 331 of the circular bottom wall 33 . thereafter , the lower annular protrusions 56 of the tube 5 can urge against a top end of the spring 6 and thus located in the upper cylindrical pipe 36 and the lower cylindrical pipe 32 of the cap 3 . furthermore , between the cap 3 and the first annular slot 55 of the tube 5 defines a first annular gap 301 ; between the cap 3 and the second annular slot 58 of the tube 5 defines a second annular gap 302 ; both of the first and second annular gapes 301 , 302 are displaceable with the tube 5 . the sealant dispensing unit 9 further includes a serving element 4 a , wherein one end of the serving element 4 a is provided with an eccentric cam 41 having two pivot pins 411 at its two sides , the other end of the serving element 4 a is provided with an operating handle 42 . the serving element 4 a is pivotally connected with the pin holes 391 of the upper cylindrical pipe 36 by the pivot pins 411 . the eccentric cam 41 of the serving element 4 a is located at the top opening 39 of the upper cylindrical pipe 36 and urging against the closed top face 510 of the top segment 51 of the tube 5 . the serving element 4 a can be operated by the operating handle 42 at the mounting slots 392 of the upper cylindrical pipe 36 to conduct a semicircle swing about the pivot pins 411 . the spring 6 , the tube 5 , and the serving element 4 a can be assembled to the cap 3 to become a cap assembly , which in turn can be assembled to the bottle 2 . as such , the lower cylindrical pipe 32 of the cap 3 and the most part of the tube 5 , such as the bottom segment 59 , are located in the inner space 22 of the bottle 2 , as shown in fig2 and 4 . in fig1 , the supportive box 1 , being substantially rectangular in shape , has a large - area top surface 11 , a large - area bottom surface 12 , and four small - area side surfaces . in another box design , the supportive box 1 has a small - area top surface 13 and a small - area bottom surface 14 . ( see fig8 ). the engagement seats 23 , 24 of the bottle 2 can be inserted into the positioning slot 15 of the supportive box 1 , so that the sealant dispensing unit 9 will not tip over . under this condition , the sealant dispensing unit 9 is installed in upright orientation . a first hose 17 has one end being connected to the compressor unit and has the other end being connected to the first hose connector 37 of the cap 3 of the sealant dispensing unit 9 . a second hose 18 has one end being connected to the second hose connector 38 of the cap 3 of the sealant dispensing unit 9 and has the other end being connected to the air nozzle 191 of the tire 19 that is intended to be inflated or repaired , as shown in fig1 . alternatively , the sealant dispensing unit 9 is installed such that it can be concealed in the positioning slot 16 of the supportive box 1 , as shown in fig8 . in the present invention , the term “ upright orientation ” means that the cap 3 of the sealant dispensing unit 9 faces upwardly while the bottom 27 of the bottom 2 faces downwardly ; the term “ inverted orientation ” means that the cap 3 of the sealant dispensing unit 9 faces downwardly while the bottom 27 of the bottle 2 faces upwardly . one feature of the present invention is that the sealant dispensing unit 9 can be installed to the supportive box 1 in upright orientation as well as inverted orientation to achieve the purpose of inflating or repairing a tire . an inverted orientation application for the sealant dispensing unit 9 is shown in fig9 . an upright orientation application for the sealant dispensing unit 9 is shown in fig1 and 8 . no matter the sealant dispensing unit 9 is installed in upright or inverted orientation , the sealant dispensing unit 9 can assembled or concealed in the positioning slot 16 of a supportive box that is designed properly . another feature of the present invention is that the first hose connector 37 and the second hose connector 38 can be changed to serve as an inlet for the high - pressure air from the compressor unit or an outlet for the chemical sealant 26 contained in the sealant dispensing unit 9 , depending on the sealant dispensing unit 9 being operated under upright or inverted orientation . fig6 shows that the sealant dispensing init 9 is installed to the supportive box 1 in upright orientation for delivering the high - pressure air . fig7 shows that the sealant dispensing init 9 is installed to the supportive box 1 in upright orientation for delivering the chemical sealant 26 . when the surface with short distance 413 of the eccentric cam 41 urges against the closed top face 510 of the top segment 51 of the tube 5 , the spring 6 is not compressed and thus the high - pressure air from the compressor unit can go through the first hose 17 , the first hose connector 37 to enter the upper cylindrical pipe 36 of the cap 3 such that the high - pressure air can enter the first annular gap 302 between the second annular slot 58 and the cap 3 , such that the first hose connector 37 can communicate with the second hose connector 38 . therefore , the second hose connector 38 can deliver the high - pressure air to inflate the tire 19 , as shown in fig6 . when the tire 19 is punctured and requires to be inflated and repaired , the user can swing the serving element 4 a to have the surface with long distance 412 of the eccentric cam 41 come into contact with the closed top face 510 of the top segment 51 of the tube 5 , as shown in fig7 . under this condition , the spring 6 is compressed , and thus the tube 5 is displaced downwardly to have the first hose connector 37 being blocked from the second hose connector 38 . therefore , the air entering the first hose connector 37 will be blocked from entering the second hose connector 38 . however , the high - pressure air can go through the slots 34 of the lower cylindrical pipe 32 , via the second annular gap 302 between the second annular slot 58 and the cap 3 , to enter the inner space 22 of the bottle 2 . as such , the high - pressure air can force the chemical sealant 26 contained in the bottle 2 to enter the tube 5 via the bottom opening 590 and the notches 591 and go upwardly along the inner passage 50 and go through the through hole 550 and the first annular gap 301 between the first annular slot 55 and the cap 3 to enter the second hose connector 38 so that the chemical sealant 26 can be conveyed to a the for a repair . as shown in fig6 and 7 , when the sealant dispensing unit 9 is installed to the supportive box 1 in upright orientation , the sealant dispensing unit 9 is not only for inflating a tire , but also for repairing a the of being punctured . when repairing a punctured tire is required , the user only requires swinging the serving element 4 a . over to the opposite side . when the sealant dispensing unit 9 is operated under upright orientation , the first hose connector 37 only afford the function of receiving the high - pressure air . the inner passage 50 of the tube 5 is only used as a channel for the chemical sealant 26 . fig9 through 11 show that the sealant dispensing unit 9 is installed to the supportive box 1 in inverted orientation . as shown , the functions of the first hose connector 37 and the second hose connector 38 have been changed . as shown in fig9 , the first hose connector 37 , which serves as an inlet for the high - pressure air when the sealant dispensing unit 9 is operated under upright orientation , will now serve as an outlet for the chemical sealant 26 ; the second connector 38 , which serves as an outlet for the chemical sealant 26 when the sealant dispensing unit 9 is operated under inverted orientation , will now serve as an inlet for the high - pressure air ; the inner passage 50 of the tube 5 , which serves as a channel for the chemical sealant 26 when the sealant dispensing unit 9 is operated under upright orientation , will now serve as a channel for the high - pressure air . referring to fig1 , since the surface of short distance 413 of the eccentric cam 41 urges against the closed top face 510 of the top segment 51 of the tube 5 , the spring 6 is not compressed . under this condition , the second hose connector 38 receiving the high - pressure air and the first hose connector 37 delivering the chemical sealant 26 are located at the region of the second annular gap 302 between the second annular slot 58 of the tube 5 and the cap 3 , and thus the second hose connector 38 and the first hose connector 37 can communicate with each other . therefore , the high - pressure air can enter the second hose connector 38 and go out of the first hose connector 37 to inflate the tire 19 . when the tire 19 requires to be repaired , the user can swing the serving element 4 a over to the opposite side to have the surface of long distance 412 of the eccentric cam 41 come into contact with the closed top face 510 of the top segment 51 of the tube 5 , as shown in fig1 . under this condition , the spring 6 is compressed and thus the tube 5 is displaced upwardly to approach the bottom of the bottle 2 . therefore , the second hose connector 38 is blocked from communicating with the first hose connector 37 . however , the high - pressure air entering the second hose connector 38 can go through the through hole 550 to enter the inner passage 50 of the tube 5 and then go into the inner space 22 of the bottle 2 above the chemical sealant 26 , and thus the chemical sealant 26 can be forced to go through the slots 34 of the lower cylindrical pipe 32 to enter the second annular gap 302 between the second annular slot 58 and the cap 3 and then go out of the first hose connector 37 . in brief , when the sealant dispensing unit 9 is operated under inverted orientation , the first hose connector 37 will provide the function of delivering the chemical sealant 26 , which is different from the function of receiving the high - pressure air when the sealant dispensing unit 9 is operated under upright orientation . furthermore , when the sealant dispensing unit 9 is operated under inverted orientation , the inner passage 50 of the tube 5 will serve as a channel for the high - pressure air , but not serve as a channel for the chemical sealant 26 . a further feature of the present invention is that the serving element 4 a can be used to control the displacement of the tube 5 to allow the sealant dispensing unit 9 to be used for only inflating a tire or for simultaneously repairing and inflating a tire . fig1 and 13 show another embodiment of the sealant dispensing unit 9 , wherein most elements of the sealant dispensing unit 9 are the same as those shown in fig3 except for the serving element . as shown in fig1 and 13 , the serving element 4 b is designed such that it can be operated to rotate about the pin hole 391 of the upper cylindrical pipe 36 . in fig3 , the serving element 4 a is operated to swing about the pin holes 391 . both of the serving element 4 a and the serving element 4 b provides the function of displacing the tube 5 . as shown in fig1 and 13 , one end of the serving element 4 b is provided with a pivot pin 431 and a transverse eccentric cam 43 at the rear of the pivot pin 431 . the other end of the serving element 4 b is provided with a rotary handle 44 , wherein the pivot pin 431 is pivotally connected to the pin hole 391 of the upper cylindrical pipe 36 . in view of the foregoing , the sealant dispensing unit 9 of the present invention can be installed to the supportive box 1 in upright orientation as well as inverted orientation to inflate or repair a tire , and this feature can facilitate an associated professional to perform various modes and designs of the supportive box in cooperation with the sealant dispensing unit 9 . furthermore , the first hose connector 37 and the second hose connector 38 of the sealant dispensing unit 9 can be used to serve as an inlet for the high - pressure air or an outlet for the chemical sealant 26 . furthermore , the tube 5 can be used to serve as a channel for the chemical sealant 26 or a channel for the high - pressure air . furthermore , the serving element 4 a and the serving element 4 b are respectively provided with the eccentric cam 41 and the eccentric cam 43 , both of which allows the tube 5 to be displaced for achieving the purpose of delivering the chemical sealant to repair a tire . the operation of the sealant dispensing unit 9 is very convenient . the descriptions set forth as above illustrate simply preferred embodiments of the present invention and are not intended to limit the scope of the present invention . it is understood that any modification , replacement of equivalent parts and improvement by those skilled in the art are within the scope of the present invention without departing the spirit and principle of the invention hereinafter claimed