Ultrasonic wave cleaning apparatus

Abstract

An apparatus for physically cleaning objects by using ultrasonic waves which employs a unique arrangement of a cleaning liquid tub and a plurality of ultrasonic wave oscillators. The arrangement is such that the cleaning tub comprises two oppositely inclined bottom walls in generally V-shaped cross-section, and the ultrasonic wave oscillators are installed on one of the inclined bottom walls of the cleaning liquid tub having a relatively smaller area than the conventional flat bottom construction. By virtue of this arrangement, the ultrasonic waves can be radiated much more effectively leaving less dead space than in the conventional construction, thus resulting in such advantageous features as remarkable improvement of the radiation effects of ultrasonic waves on the object to be cleaned and effective reduction of the number of ultrasonic wave oscillators without sacrificing the ultrasonic wave cleaning effect.

Description

BACKGROUND OF THE INVENTION

The present invention relates generally to an art in the field of physical cleaning and particularly to an ultrasonic wave cleaning apparatus. More particularly, this invention is concerned with an ultrasonic wave cleaning apparatus of laterally inclined radiation type which is adaptable for a medical bacteria-free cleaning treatment to objects such as doctors' hands and medical instruments to be cleaned prior to a surgical operation.

It has been well known to use ultrasonic waves for removing oils and other contaminants off from instruments. For such a purpose, conventional ultrasonic wave cleaning apparatus have employed an ultrasonic wave radiation system in which a plurality of ultrasonic wave oscillators are arranged horizontally along a flat horizontal bottom of a cleaning liquid chamber of the apparatus. With such an arrangement of the ultrasonic wave oscillators, unless such wave oscillators are provided in quantity in proportion to the area of the bottom of the cleaning liquid chamber, substantial effect of ultrasonic cleaning cannot be obtained as desired, and therefore, it has been necessary with such conventional arrangement to dispose a plurality of ultrasonic wave oscillators with appropriate spaces between each other extensively throughout the whole bottom area of the chamber.

When it is desired to have an incresed effect of ultrasonic cleaning in the design of such apparatus, it has been a practice to increase the number of ultrasonic wave oscillators to be provided along the bottom area of the chamber. In this respect, the cost of such oscillators per one cleaning apparatus inevitably became considerably large, which cost sometimes amounted to almost a third of the total price of the apparatus, thus resulting in a costly apparatus, and this fact was an obstacle to extensive use of such apparatus.

In addition, when such an apparatus of the conventional arrangement is used for a hand-cleaning or a therapeutical treatment, an effective ultrasonic wave cleaning performance is obtained with respect to skin surfaces such as of the fingers, etc., as the cleaning liquid is caused to positively pass into the surfaces of such objects in an extremely short period.

However, it has been experienced that there is no substantial effect obtained specially in the nailback portions of the fingers which are most likely to be contaminated by bacteria and so much so that the nailback portions should essentially be cleaned bacteria-free in this particular application. This is because the radiation of ultrasonic waves tends to be diffused at random due to the horizontal arrangement of the ultrasonic wave oscillators on the bottom of liquid chamber, and consequently, no substantial ultrasonic wave cleaning effect is obtained in the nailback portions of the fingers which require a strongly concentrated radiation of ultrasonic waves for striking and removing the contaminants lodged therein.

SUMMARY OF THE INVENTION

It is therefore a primary object of this invention to provide an ultrasonic wave cleaning apparatus which is free from the above mentioned drawbacks and which ensures an enhanced and improved ultrasonic wave radiation effect.

According to this invention, there is provided an ultrasonic wave cleaning apparatus including a plurality of ultrasonic wave oscillating means on the wall of a cleaning liquid tub adapted for radiating ultrasonic waves into the body of cleaning liquid contained in the tub, the cleaning apparatus incorporating the improvement comprising a bottom wall inclinedly extending upwardly toward one side of the cleaning liquid tub and a plurality of ultrasonic wave oscillating means arranged on the other side of the tub, the ultrasonic wave oscillating means being mounted to radiate beams of ultrasonic waves in an obliquely upward direction generally parallel with the inclined bottom wall.

A preferred embodiment of the invention will now be described by way of example and with reference to the accompanying drawing in which like parts are designated by like reference numerals.

BRIEF DESCRIPTION OF THE DRAWING

In the drawing:

FIG. 1 is a side elevational view, partly in vertical section, showing the interior arrangement of an ultrasonic wave cleaning apparatus of inclined radiation type according to this invention, and

FIG. 2 is a top plan view of the apparatus shown in FIG. 1.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Referring now to the accompanying drawing, there is shown a cleaning tub 2 which defines a cleaning liquid chamber W. The cleaning tub 2 has a bottom of V-shaped cross section which comprises a laterally inclined bottom wall 2a and another oppositely inclined bottom wall 2b ; as seen in FIG. 1 wall 2b has a greater inclination with respect to the horizontal as compared to that of wall 2a. Wall 2a thus has a greater length than wall 2b . The inclined bottom wall 2a extends obliquely upwardly from the bottom corner towards one lateral side of a casing 3. In an opening provided in the inclined bottom wall 2b , there are provided a plurality of ultrasonic wave oscillators 4 each of which has a high frequency coil 4b wound around an iron core 4a so as to produce ultrasonic waves as specified. This arrangement is specifically designed for keeping to a minimum a dead space or area where there is no substantial effect of ultrasonic waves radiated from the ultrasonic wave oscillators 4 with respect to a cleaning liquid contained in the cleaning liquid chamber W.

These ultrasonic wave oscillators 4 are, for instance, bonded in position on a base plate 6 by using a suitable adhesive, and the marginal portion of the base plate 6 is secured fluidtightly on the sides 7 of the opening in the inclined bottom wall 2b of the cleaning tub 2 by a plurality of screws 8 with a suitable packing (not shown) therebetween. An auxiliary liquid chamber 9 is provided for receiving therein the cleaning liquid overflowing from the liquid chamber W when an object to be treated is immersed into the liquid in the liquid chamber W, the auxiliary chamber 9 being separated by a partition or weir 10 from the cleaning liquid chamber W.

At the bottom of the auxiliary chamber 9, there is provided a cleaning liquid drain hole 11 having therein a filter 11a , the drain hole communicating with a three-way valve 13 through a pipe 12. One delivery port of the three-way valve 13 is connected to the suction side of a pump 15 through a pipe 14, while the other delivery port of the three-way valve 13 is connected to a drain cock 18 through pipes 16 and 17.

On the other hand, a drain pipe 19 opening at the bottom of the cleaning tub 2 is communicatively connected with the abovementioned pipe 17. The delivery side of the pump 15 is connected through a pipe 21 to cleaning liquid discharging outlets 22 which are formed in the base plate 6 of the ultrasonic wave oscillations 4. There is further provided a high frequency generator 20 at the bottom of the casing 3. In the above described arrangement of the ultrasonic wave cleaning apparatus, the cleaning tub 2 is filled with the cleaning liquid.

In operation, an object to be treated or cleaned is immersed in the cleaning liquid in the chamber W and a radio frequency current from the ultrasonic wave generator 20 is applied to the oscillating coils 4b of the ultrasonic wave oscillators 4, whereby ultrasonic waves are radiated from the oscillators 4 disposed on the obliquely inclined bottom wall 2b of the cleaning tub 2 in a variety of directions with respect to the inclined bottom wall 2a of the cleaning tub 2 as indicated by phantom arrows in FIG. 1, such as more or less obliquely upwardly, in parallel, or more or less obliquely downwardly with respect to the inclined bottom wall 2a of the cleaning tub 2.

Among these ultrasonic waves, portions or beams of ultrasonic waves radiated in relatively downward radiating directions so as to collide at certain varied angles with the bottom wall 2a will be reflected so as to be redirected into the body of the cleaning liquid in the cleaning tub 2 according to the angles of incidence to the wall 2a. Consequently, there occur a variety of irregular reflections of ultrasonic waves on the inclined bottom wall 2a, and this results in relatively uniformly distributed radiations of the ultrasonic waves throughout the cleaning tub 2.

As a consequence of the above described radiating operation, there is obtained a generally upward radiating effect of ultrasonic waves with respect to the cleaning liquid in the cleaning tub 2, so that the cleaning liquid is as a whole exposed to such radiation of ultrasonic waves from the bottom portion towards the upper portion thereof, and there remains only a small portion of the liquid existing at the upper right side of the cleaning tub 2 as viewed in FIG. 1 that is not well subjected to the radiation of ultrasonic waves, whereby the object immersed in the cleaning liquid is subjected to generally uniform radiating effects of ultrasonic waves throughout almost all of the portions thereof. The best cleaning effect is obtained particularly on the part of the object which faces the inclined bottom wall 2a.

When the three-way valve 13 is changed over so as to connect the pipe 12 with the pipe 14, and a motor M is operated to drive the pump 15, the cleaning liquid is sucked by the pump 15 from within the auxiliary liquid chamber 9 through the pipe 12 and then delivered via the pipe 21 and the discharging outlets 22 back into the liquid chamber W. An extra quantity of the cleaning liquid in the cleaning liquid chamber W overflows into the auxiliary liquid chamber 9, and the liquid is thus repeatedly recycled to the liquid chamber W.

Since jet streams of the cleaning liquid are ejected out of the discharging outlets 22 located at the bottom portion of the tub 2, there is produced a recirculation flow or convection of the cleaning liquid within the cleaning tub 2. The jet streams of the cleaning liquid cause dislodging of the contaminants on the surfaces of the object being treated in the cleaning tub 2. When the surfaces of the object thus made free from contaminants are further exposed to the abovementioned effects of ultrasonic waves, a remarkably improved cleaning effect can be obtained.

The contaminants removed from the surfaces of the object are then directed into the auxiliary liquid chamber 9, being entrained by the cleaning liquid, and are finally trapped by the filter 11a in the drain hole 11. Consequently, the cleaning liquid to be recycled to the tub 2 is made free from contaminants.

In the practice of the cleaning apparatus of this invention, a preferred frequency range of ultrasonic waves was found to be between 20 and 38 KHz, and a preferred output range of ultrasonic waves between 0.1 and 0.2 Watt/cm.sup.2.

From the results of breeding experiments on the staphylobacillus and staphylococcus in the nailback portions of the human fingers by using the ultrasonic cleaning apparatus of the conventional horizontal bottom arrangement, it was found that the number of colonies (quantitative unit of bacteria) increased from 98 colonies up to 186 colonies, which was a considerably adverse effect due to the use of such ultrasonic wave cleaning apparatus. In contrast, when the ultrasonic wave cleaning apparatus of laterally inclined oscillator arrangement according to this invention was used, experiments under identical conditions in terms of the same staphylobacillus and staphylococcus in the nailback portions of the fingers produced a remarkable result in that the number of colonies decreased from 205 to 0 with a single cleaning operation.

In summary, the ultrasonic wave cleaning apparatus according to this invention has the following advantageous features. First, the time required for the cleaning operation can be made remarkably shorter than by the conventional arrangement, so much so that the service life of the apparatus can be substantially prolonged. Second, equal cleaning effect can be attained by applying only about one-third output of ultrasonic waves in comparison with the conventional arrangement, thus resulting in considerable savings in economy. In addition, a substantial reduction in the number of ultrasonic wave oscillators is accordingly possible while maintaining equal cleaning performance, thus considerably contributing to a further wider application of the ultrasonic wave cleaning apparatus.

While this invention has been described above with respect to only an application thereof to a handcleaning operation for doctors prior to a surgical operation, this does not mean in any way a limitation of this invention, but on the contrary, this invention can likewise be applied to many other uses such as, for instance, for cleaning medical devices and instruments by commonly using special medical fluids.

Claims

What is claimed is:

1. In an ultrasonic wave cleaning apparatus including an open-top cleaning liquid tub having a bottom of V-shaped cross section, including a pair of first and second oppositely inclined bottom walls, and ultrasonic wave oscillating means on said first bottom wall to radiate ultrasonic waves into a cleaning liquid contained in said tub:

an improvement wherein said second bottom wall is less inclined with respect to the horizontal than said first bottom wall so as to extend obliquely upwardly over a greater length than said first bottom wall, said ultrasonic wave oscillating means being oriented to radiate the ultrasonic waves obliquely upwardly along and parallel to said second bottom wall, said tub being fully open upwardly at the upper edge of the bottom walls.

2. An ultrasonic wave cleaning apparatus as claimed in claim 1, further comprising means for injecting said cleaning liquid into said cleaning liquid tub.

3. An ultrasonic wave cleaning apparatus as claimed in claim 2, further comprising means for sucking said cleaning liquid from within said cleaning liquid tub and recirculating said liquid to said injecting means.

4. An ultrasonic wave cleaning apparatus as claimed in claim 3 wherein said sucking means includes liquid pumping means.

5. An ultrasonic wave cleaning apparatus as claimed in claim 3, further comprising change-over means disposed in said sucking and recirculating means to selectively direct said cleaning liquid to said cleaning liquid tub through said pump and said injecting means, or to a drain.

6. An ultrasonic wave cleaning apparatus as claimed in claim 2 wherein said injecting means includes means for directing the cleaning liquid in a direction generally parallel with said inclined bottom wall.

7. An ultrasonic wave cleaning apparatus as claimed in claim 1 further comprising an auxiliary liquid tub adjoining said cleaning liquid tub, and weir means between said tubs for overflowing of said cleaning liquid from said cleaning liquid tub into said auxiliary tub.

8. An ultrasonic wave cleaning apparatus as claimed in claim 1, further comprising filter means adapted to filter said cleaning liquid flowing out of said cleaning liquid tub.