GB2174150A

GB2174150A - Air pump

Info

Publication number: GB2174150A
Application number: GB08510703A
Authority: GB
Inventors: Minoru Ichikawa
Original assignee: JAPAN CRYSTAL IND
Current assignee: JAPAN CRYSTAL IND
Priority date: 1985-04-26
Filing date: 1985-04-26
Publication date: 1986-10-29
Also published as: HK97191A; GB8510703D0; GB2174150B; SG80191G

Abstract

An air pump for suppling air into water especially in aquaria is disclosed which comprises a vibrating arm (26) having free ends, a permanent magnet (28) fastened to at least one of the ends of the arm, two housings (20, 20') disposed parallel to each other along the length of the arm, each capped by a diaphragm (25, 25') attached to the arm and a driving electromagnet (17) the core (18) of which is opposed to the end of the arm (26) having the permanent magnet (28) thereon. Of the two housings (20, 20'), at least the one (20) disposed nearer to the driving electromagnet (17) is provided with an air suction valve (21) and an air discharge valve (22), whereby the excitation of the driving electromagnet causes the arm to be vibrated about a point (a) falling between the fixed portions of the two diaphragms. As shown in Fig. 4 the output of the pump can be controlled by adjusting valve (32), so building up a back pressure in housing (20') which governs the position of point 'a' about which arm (26) pivots and so governs the pumping stroke. <IMAGE>

Description

SPECIFICATION Air pump This invention relates to improvements in and concerning an air pump for supplying air into water, particularly into water in an aquarium.

The conventional air pump generally comprises, as illustrated in Figure 1, a case 1, a shaking arm 3 disposed in the case 1 as pivotally supported at one end thereof by a support member 2 and provided at the other end thereof with a permanent magnet 4, a driving electromagnet 7 formed by winding a coil 6 on a core 5 as disposed inside the case 1 with the core 5 opposed to the permanent magnet 4, a diaphragm 9 fitted on a valve housing 8 and set fast in place with a pin 10 on the shaking arm 3 partway along the length thereof, an air suction inlet 12 formed on the valve housing 8 on the side incorporating a suction valve 11 and an air discharge outlet 14 formed on the valve housing 8 on the side incorporating a discharge valve 13, and a tube 15 connected at one end thereof to the aforementioned air discharge outlet 14 and at the other end thereof to an air stone inside an aquarium.When the driving electromagnet 7 is excited by supply of alternating current, the shaking arm 3 is vibrated about the support member 2 by the interaction between the rapidly alternating N and S poles generated in the core 5 and the magnetic poles of the permanent magnet 4, and the diaphragm 9 alternately inflates and shrinks to a slight degree so as to suck in air through the air suction inlet 12 and discharge air through the air discharge outlet 14 by virtue of the valves 11,13.

The air pump constructed as described above entails the following drawbacks.

The first drawback resides in the fact that when the driving electromagnet 7 is excited and the shaking arm 3 is vibrated to vibrate the diaphragm 9, even if the vibration is started about a center of vibration wherein the permanent magnet 4 remains near the center between the opposite ends of the core 7 (which is the optimum position), the diaphragm 9 tends to inflate with continued operation until the center of vibration reaches the position indicated by chain line in Figure 1, which is far removed from the optimum position. As a results, the discharge of air is not sufficient because the amplitude of vibration of the shaking arm 3 is decreased and the change in the positon of the diaphragm 9 between its inflated and shrunken states is small.

The second drawback resides in the fact that while one end of the shaking arm 3 should be supported in place without inducing any frictional resistance, the supporting of the shaking arm 3 actually cannot be attained with the frictional resistance reduced to zero. When the shaking arm 3 is shaken, therefore, the friction loss generated by the support member 2 goes to reduce the amplitude of vibration of the shaking arm. Also by this reason, the discharge of air is not sufficient.

Another drawback lies in the fact that with elapse of time, the support member gradually wears and eventually reaches the point of ceasing to offer required support to the shaking arm 3 and, as a result, the shaking arm slips off the support member to interrupt the operation of the pump.

The present invention has been accomplished with a view to overcoming the drawbacks described above. Specifically, the present invention aims to provide an air pump which permits sufficient supply of air into water without substantially entailing trouble.

The air pump according to the present invention comprises a shaking arm having the opposite ends in free state, a permanent magnet disposed on at least one of the opposite ends of the shaking arm, two valve housings parallelly disposed in the direction of the length of the shaking arm, each capped with a diaphragm and provided with an air suction inlet and an air discharge outlet, the two diaphragms being fastened to the shaking arm as separated by a prescribed space, and a driving electromagnet having the core thereof opposed to the permanent magnet side end of the shaking arm, whereby the excitation of the driving electromagnet causes the arm to be vibrated about a point between the portions attached to the two diaphragms.

Air pumps according to the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a schematic view of a conventional air pump.

Figure 2 is a schematic view illustrating the basic construction of an air pump according to the present invention.

Figure 3 through Figure 6 are schematic views each illustrating an air pump according to the present invention.

Figure 2 shows the basic construction of an air pump according to the present invention.

A driving electromagnet 1 7 disposed inside a case 16 comprises a U-shaped core 18 and a coil 19 wound around one of the shanks of the core 18. Inside the case 16, two valve housings 20, 20' are parallelly disposed.

One of the housings indicated by 20 is provided internally with an air suction valve 21 and an air discharge valve 22. It is further provided on the air suction valve 21 side thereof with an air suction inlet 23 and on the air discharge valve 22 side thereof with an air discharge outlet 24. The other valve housing 20' is not internally provided with an air suction valve or an air discharge valve but is provided with an air suction inlet 23' and an air discharge outlet 24' which both communi cate with the interior of the housing.

The two housings are capped with diaphragms 25, 25'. A slender shaking arm 26 is fastened by pins 27, 27' to the two diaphragms 25, 25'. The opposite ends of this shaking arm 26 are not supported by the case 16 but are in free state. The shaking arm 26 is provided at one end thereof with a permanent magnet 28. This permanent magnet is disposed opposite the opening separating the two leading ends of the U-shaped core 18. Of the aforementioned valve housings, 20, 20', the valve housing 20, which is provided internally with the air suction valve and the air discharge valve, is disposed nearer to the electromagnet 17 and the valve housing 20' provided with neither an air suction valve nor an air discharge valve is disposed farther from the electromagent 17.The air discharge outlet 24 of the valve housing 20 and the air suction inlet 23' of the valve housing 20' are interconnected by an air path 29. An air discharge path 30 is connected to the air discharge outlet 24' of the valve housing 20'. The remaining end of the aforementioned air discharge outlet 30 is connected to an air stone inside the aquarium (not shown).

The basic construction of the air pump of the present invention is as described above.

When an alternating current is passed through the coil 19 of the electromagnet 17, the shaking arm 26 is set in vibration by the magnetic action between the alternating N and S poles generated at the leading end portions of the core 18 and the permanent magnet 28. In this case, owing to the initial vibration of the shaking arm 26, the inner pressure is heightened to a certain degree in each of the valve housings 20, 20' and the diaphragms 25, 25' are proportionately inflated. The condition so assumed by the diaphragms 25, 25' represents the standard position for the vibration of the shaking arm (dotted line in Figure 2). The vibration is produced based on this standard position. In its vibrated condition, the shaking arm 26 swings about a point or node "a" as its center. When the diaphragm 25 is inflated, the other diaphragm 25' is contracted.When the diaphragm 25 is contracted, the other diaphragm 25' is inflated. When the diaphragms 25 is inflated, the air is sucked in via the air suction inlet 23 into the valve housing 20 by the action of the air suction valve 21. When the diaphragm 25 is contracted, the air held inside the valve housing 20 is discharged through the air discharge outlet 24 by the action of the air discharge vavle 22. The air discharged via the air discharge outlet 24 advances through the air path 29 into the valve housing 20' and departs from the air discharge path 30.

When the electromagnet 17 is excited, therefore, the shaking arm 26 is set in vibration despite the fact that it is not pivotally attached at either end. Thus, the air pump is allowed to fulfill its function fully.

Owing to the operation of the diaphragms 25, 25', the point "a" is enabled to occur between the portions (pins 27, 27') at which the shaking arm 26 is fixed to the diaphragms 25, 25'. To be precise, the point "a" is slightly toward the diaphragms 25' from the center between the two portions of fixation.

This phenomenon is ascribable to the presence of the permanent magnet 28 at one end of the shaking arm 26 and the absence of a permanent magnet at the other end, namely the lack of balance between the opposite ends of the shaking arm 26. While the shaking arm 26 is in the state of vibration, the conditions of inflation and contraction of the diaphragm 25 change more than those of inflation and contraction of the diaphragm 25'.

Figure 3 depicts another air pump embodying the present invention. The shaking arm 26 is provided at one end thereof with a permanent magnet 28 and at the other end thereof with a permanent magnet 31 which is identical with the permanet magnet 28. The former permanent magnet 28 is opposed to the opening in the electromagnet 17. The two valve housings 20, 20' are provided with air suction valves 21, 21' and air discharge valves 22, 22' respectively. The air discharge path 30 is connected in common to the air discharge outlet 24, 24' respectively of the two valve housings 20, 20'.Further, in the shaking arm 26, the portions at which the diaphragms 25, 25' are fixed to the shaking arm 26 with pins 27, 27' are symmetrical, so that the length from the permanent magnet 28 to the fixed portion of one diaphragms 25 is equal to the length from the other permanent magnet 31 to the fixed portion of the other diaphragm 25'.

In the present embodiment, therefore, the shaking arm 26 is well balanced. When the electromagnet 17 is excited and the shaking arm 26 is set in vibration, the point "a" falls exactly at the center between the fixed portions of the two diaphragms. As a result, the conditions of inflation and contraction caused by the shaking arm are equal between the two diaphragms 25, 25' and the air discharge outlets 24, 24' of the valve housings 25, 25' alternately discharge an equal volume of air. In this embodiment, the magnet 31 is disposed as described above for the purpose of counterbalancing the weight of the magnet 21.

Thus, it may be replaced with some other object which is capable of fulfilling the purpose just mentioned.

Figure 4 depicts yet another air pump embodying the present invention. This embodiment differs in construction from that of Figure 3 in respect that the air path 30 is connected to the air discharge outlet 24 of the valve housing 20 disposed closer to the electromagnet 17 and an air discharge path 33 provided with a control valve 32 is connected to the air discharge outlet 24' of the valve housing 20' disposed farther from the electromagnet 17. Since Figure 4 is the same as Figure 3 except for the points described above, description of its construction is omitted.In the air pump constructed as described above, when the control valve 32 is closed and the electromagnet 17 is excited to set the shaking arm 26 in motion, the diaphragm 25 of the valve housing 20 disposed nearer to the electromagnet 17 is alternately inflated and contracted and the air introduced via the air suction inlet 23 is forced out into the air path 30 via the air discharge outlet 24. Since the air discharge outlet 24' of the other valve housing 20' is kept in a closed state in this case, the inner pressure of the valve housing 20' gradually increases and causes the diaphragms 25' to be inflated to the point of ceasing the alternation of inflation and contraction.As a result, the point "a" of the shaking arm now in a vibrating state shifts from the center between the two diaphragms toward the diaphragm 25' which is gradually inflating and finally reaches the fixed portion of the inflated diaphragm 25'. Thereafter, the shaking arm vibrates about this fixed portion as its fulcrum. Thus, the extents of inflation and contraction caused in the diaphragm 25 can be increased and the amount of air discharged can be proportionately increased.

In the air pump of Figure 4 operated as described above, the control valve 32 can be adjusted so as to control the inner pressure of one of the valve housings and consequently change the position of the fulcrum point of the shaking arm as desired. Thus, the volume of air discharged can be continuously and appreciably varied by adjusting the alternate inflation and contraction of the other diaphragm.

In Japan, depending on the district, commercial line current is supplied at 50 cycles or 60 cycles and whether an air pump will operate efficiently at one of these cyclages normally depends on the length of the shaking arm and the resilient force of the diaphragms.

In accordance with the embodiment of Figure 4, however, since the change of the position of the fulcrum point constitutes itself a substantial change in the length of the shaking arm, the air pump is enabled to operate most efficiently without reference to the cycle of the alternating current by suitably adjusting the volume of air flowing through the air discharge path 33 with the control valve 32 and setting the fulcrum point appropriately.

Figure 5 depicts still another air pump embodying the present invention. This embodiment differs in construction from that of Figure 3 in respect that two electromagnets 17, 17' are disposed as opposed to the permanent magnets 28, 31 at the opposite ends of the shaking arm 26.

When the electromagnets 17, 17' are opposed to the opposite ends of the shaking arm 26 as in the present embodiment, the shaking arm 26 is caused by the excitation of the two electromagnets 17, 17' to vibrate powerfully about the point "a", with the result that the diaphragms 25, 25' are alternately inflated and contracted to induce discharge of air through the air discharge path 30 connected in common to the air discharge outlets 24, 24' respectively of the valve housings 20, 20'.

Figure 6 depicts another air pump embodying the present invention. Inside the case 16, two sets each of laterally paired valve housings 20, 20' are disposed as vertically opposed to each other. Two shaking arms 26a, 26b are fastened one each to two sets each of laterally paired diaphragms 25, 25' adapted to cap the valve houses 20, 20'. The shaking arms 26a, 26b are each provided at the opposite ends thereof respectively with permanent magnets 28, 31. The two electromagnets 17, 17' disposed in the opposite end portions of the interior of the case 16 are opposed to the permanent magnets 28, 31. Thus, the two shaking arms 26a, 26b are laid parallelly to each other.

In the present embodiment, therefore, when the two electromagnets 17, 17' are excited, the magnetic action generated between the two electromagnets 17, 17' and the permanent magnets 28, 31 sets the shaking arms 26a, 26b in vibration and the operation of the diaphragms induces discharge of air through the air discharge paths 30a, 30b. In this embodiment, the cores 18, 18' of the electromagnets 17, 17' are in the shape of the letter E so that the permanent magnets may be opposed to the openings separating the adjacent leading ends of the core.

In the embodiments of Figure 5 and Figure 6 described above, when the alternating current is passed in one same direction through the coils 19, 19' of the two electromagnets 17, 17', the surfaces of the permanent magnets 28, 31 disposed at the opposite ends of the shaking arm(s) 26 (26a, 26b) which are directed toward the corresponding electromagnets are polarized oppositely. When the alternating current is passed in opposite directions through the cores 19, 19' of the two electromagnets, however, the aforementioned surfaces of the permanent magnets 28, 31 disposed at the opposite ends of the shaking arms are similarly polarized. As a result, the shaking arms are each enabled to vibrate about the point "a" at the center of the fixed portions of the diaphragms.

As is clear from the foregoing description, the present invention can reduce the deviation of the permanet magnet due to the change of the position of the shaking arm during the inflation of the diaphragm while the air pump is in operation because the shaking arm is supported in place by two diaphragms without requiring either of the opposite ends thereof to be pivotally attached. The magnetic action generated between the electromagnet and the permanent magnet is highly effective and the vibration produced by the shaking arm is powerful enough for the inflation and contraction of the diaphragm to be effected powerfully and for the amount of air discharged to be increased. Since the shaking arm is not pivotally attached, the diaphragm is operated efficiently without entailing any mechanical frictional loss. This invention, accordingly, provides an air pump of high economic value.

Claims

1. An air pump comprising a shaking arm having the opposite ends thereof in free state, a permanent magnet disposed on at least one of the ends of said shaking arm, two valve housings parallelly disposed in the direction of the length of said shaking arm, each capped with a diaphragm and provided with an air suction inlet and an air discharge outlet, said two diaphragms being fastened to said shaking arm as separated by a prescribed space, and a driving electromagnet having the core thereof opposed to the permanent magnet side end of said shaking arm, whereby the excitation of said driving electromagnet causes said arm to be vibrated about a point between the portions attached to said two diaphragms.

2. An air pump according to claim 1, wherein of said two valve housings, at least the valve housing disposed nearer to said driving electromagnet is provided internally with an air suction valve and an air discharge valve.

3. An air pump according to claim 1, wherein said shaking arm is provided with permanent magnets at both ends.

4. An air pump according to claim 1, wherein the air discharge outlet of one of said two valve housings is connected to the air suction inlet of the other valve housing.

5. An air pump according to claim 1, wherein the air discharge outlets of the two valve housings are connected to one common air discharge path.

6. An air pump substantially as hereinbefore set forth with reference to and/or as illustrated in Figures 2 to 6 of the accompanying drawings.