A DISCHARGING ELECTRODE SOCKET

TECHNICAL FIELD

This invention relates to a discharging electrode socket of a corona discharged ionizer. More specifically, this invention relates to an apparatus that ionizes CDA (clean dried air) spouted from nozzles and transfers generated ions effectively in order to eliminate electrostatic charge accumulated on a charged object, and that enhances the efficiency of neutralization by spouting high pressure of optimal amount of ionized CDA (clean dried air) by improving the structure of a discharging electrode socket attached to a bar type ionizer which comprises a discharging electrode, a ground electrode, a high voltage generation unit, and a controller and generates ions by corona discharge.

BACKGROUND ART

Generally, ions generated from a discharging electrode should be sufficiently transferred to desired neutralization distance with optimized amount of air to enhance the efficiency of neutralization in an electrostatic eliminator, and the amount and pressure of the spouted air should be controlled arbitrarily for the transmission.

However, there are still a lot of problems to be solved about the structure of CDA spouting nozzle to use ionized air more effectively, though there have been a lot of technical developments about the air ionization using discharging bar according to the common use of corona discharged ionizers in many fields for eliminating electrostatic charge.

The problems arising while ionized CDA is spouted in the previous ionization apparatus are excessive use of CDA, decrease of neutralization distance because of low spouting pressure, decline of ion generating efficiency by particles fouled on the discharging electrode tip when used long time, etc. Though several improved apparatus (for example, an apparatus comprising a nozzle independent from CDA spouting nozzle, formed on the discharging electrode socket and eliminates dust and particles on and around the discharging electrode) were developed, radical method for preventing contamination of the discharging electrode by dust or particle has not been provided yet.

DISCLOSURE TECHNICAL PROBLEM

Consequently, a purpose of this invention is to improve efficiencies of eliminating electrostatic charge and preventing contamination of the discharging electrode by minimizing the amount of spouted CDA to reduce the drop of pressure in the air

chamber and by increasing the spouting pressure to increase spouting distance and spouting velocity, which are accomplished by improving the cross sectional area, shape, and location of spouting nozzles comprised in the discharging electrode socket which is one of the main parts of a corona discharged ionizer. Another purpose of this invention is to increase neutralization distance by decreasing the amount of spouted CDA, accordingly increasing the pressure in the air chamber, and accordingly increasing the spouting velocity, which are accomplished by designing the CDA spouting nozzle very small compared to previous devices. Another purpose of this invention is to prevent contamination of the discharging electrode by spouting high pressure CDA in turbulent flow at high velocity.

Another purpose of this invention is to provide an ionization apparatus which has improved efficiency and adaptability and can be easily managed by designing the discharging electrode socket whose cross sectional area is different from that of the spouting nozzle can be easily attached/detached, which lets the user select the neutralization distance and the velocity of spouted CDA.

Other purposes and merits of this invention will become clear upon reading the detailed explanation and referring to the attached drawings.

TECHNICAL SOLUTION A preferred embodiment of a discharging electrode socket attached to a corona discharged ionizer according to this invention comprises a discharging electrode, a ground electrode, a high voltage generation unit, and a controller, which ionizes CDA (clean dried air) spouted from nozzles and transfers generated ions in order to eliminate electrostatic charge accumulated on a charged object, wherein not less than two nozzles having the same cross sectional area do not surround the whole discharging electrode, and contact with said discharging electrode in the direction of the axis of said discharging electrode. In figure Ia, two nozzles (10) are provided facing each other on the end of the socket hole (15). As the discharging electrode (20) is inserted through the socket hole (15) as shown in figure 8, the socket hole (15) is closed by conic part of the discharging electrode (20). However, the nozzle (10) positioned outside of the socket hole (15) is not closed, and accordingly air is spouted from the nozzle. In figure 8, cross section of the nozzle is square and the nozzle passes through the socket in the direction of the axis along the discharging electrode (20). The end of the discharging electrode (20) is the shape of circular cone, and the air spouted from two nozzles (10) brushes against the conic part of the discharging electrode (20), so the discharging electrode is not contaminated. Cross section of the nozzle can have various forms like a circle,

triangle, or semicircle, and more than two nozzles can be provided.

In this embodiment, it is preferable that the cross sectional area, shape, or position of the spouting nozzle comprised in said discharging electrode socket is controlled, and CDA generated is spouted toward a charged object at high pressure in order to optimize the amount of ionized CDA which is spouted according to required neutralization distance and used amount of CDA; wherein the spouting nozzle (10) spouts CDA at high speed parallel to the nozzle attached to the discharging electrode (20) to reduce the amount of CDA for preventing the contamination of the discharging electrode (20). hi this embodiment, it is preferable that input pressure of said spouted CDA is 0.05-1.5 MPa, internal pressure in the air chamber is 0.05-1.5 MPa, amount of spouted CDA is 0.5-100LPM.

In this embodiment, it is preferable that the shape of the cross section of said spouting nozzle is triangle, square, semicircle, or polygon which can form a passage.

In this embodiment, it is preferable that spouting velocity of CDA from said spouting nozzle is 60-1500 m/sec.

ADVANTAGEOUS EFFECTS

The discharging electrode socket in this invention can effectively change required neutralization distance and amount of CDA used for the ion transmission because the cross sectional area of the spouting nozzle can be controlled arbitrarily compared to the previous nozzle, can save the amount of CDA, and can prevent the contamination of the discharging electrode for a long time because the spouting nozzle has spouting angle parallel to the axis of the discharging electrode and spouts CDA at high speed in the direction of the axis of the discharging electrode.

DESCRIPTION OF DRAWINGS

Figure 1 presents discharging electrode sockets. Figure Ia, Ib are this invention, figure Ic, Id, and Ie are prior arts.

Figure 2 presents change of internal pressure in air chamber corresponding to CDA input pressure according to the sort of the discharging electrode socket.

Figure 3 presents change of amount of CDA spouting corresponding to internal pressure in air chamber according to the sort of the discharging electrode socket.

Figure 4 presents a test environment of change of neutralizing efficiency according to the cross sectional area of the nozzle. Figure 5 and figure 6 present degree of contamination after operated for 360 hours continuously. Figure 5 is a prior art and figure 6 is this invention.

Figure 7 is a cross sectional view of a discharging electrode socket according to this invention, figure 8 is an enlarged diagram of part A in figure 7.

Figure 9 presents a bar type ionizer to which discharging electrode sockets according to this invention are attached. < Name of important part in drawings > 10: nozzle 15: socket hole 20: discharging electrode 40: CPM(charged plate monitor) 50: bar type ionizer 55: air chamber

100: discharging electrode socket dl: 600mm d2: 740mm

BEST MODE

This invention was made based on the idea that when the amount of spouted air is small and high pressure is maintained by minimizing cross sectional area of the spouting nozzle, the neutralization distance is increased and the neutralization effect compared to used amount of air is improved.

The electrostatic eliminator used in this invention is a corona discharged ionizer which comprises a discharging electrode generating corona discharge, a ground electrode inducing ion generation from said discharging electrode to which voltage was supplied, a discharging electrode socket having air nozzles which spouts CDA in a constant pressure to transfer the ions generated at the discharging electrode to a charged object, a high voltage generation unit generating AC pulse high voltage and supplying it to said discharging electrode.

The electrostatic eliminator further comprises a controller to control the amount of plus and minus ions generated from the discharging electrode arbitrarily by controlling the frequency and duty ratio of the AC pulse high voltage, an air chamber being connected to the discharging electrode socket and supplying the air injected from an air injection unit to the discharging electrode socket, and a means being connected to the discharging electrode and reducing the electric current which flows through the discharging electrode. A proper condition using the electrostatic eliminator is that input power is AC 110-240 volt, frequency is 50-60 hertz, duty ratio is 30-70%, residual voltage is within

±50 volt, and ozone concentration is 0.004~0.005ppm. It is preferable that the material of main body of said electrostatic eliminator is non-flammable ABS, the material of cover is stainless, the material of the electrode is tungsten with 99.99 degree of purity, and said electrostatic eliminator is normally operated under temperature 0-50 "C and humidity 35-85% RH.

Compared to apparatus having said condition, the characteristics of this invention is that since cross sectional area of the spouting nozzle (10) attached to the discharging electrode socket (100) is minimized, change of internal pressure in the air chamber (55) is small even a lot of discharging electrode sockets are attached horizontally, which can make the velocity of CDA spouted to the discharging electrode socket (100) continuously fast and improve the neutralization effect. (See figure 9.) We tested neutralization efficiency of a bar type ionizer (50) having 10-40 discharging electrode sockets (100) of this invention which have the same cross sectional areas but different shapes, under the above operation condition of a electrostatic eliminator. The ionizer as shown in figure 9 has the air chamber (55) and the CDA is supplied to the air chamber from outside. Since the discharging electrode socket (100) is sealed by the air chamber (55), the CDA supplied is spouted only from the nozzle (10). At this time, if the pressure in the air chamber (55) is lower than the pressure of the air flown in, the pressure in each discharging electrode socket (nozzle) becomes irregular and the spouting velocity at each discharging electrode socket becomes different. And if the pressure of the air flown in is the same with the pressure in the air chamber (55), the pressure in each discharging electrode socket (100) is regular and the spouting velocity at each discharging electrode socket becomes regular, too. Since the velocity is inversely proportional to the cross sectional area when spouted amount is the same, if the nozzle (10) becomes smaller the velocity becomes higher.

If the nozzle (10) in the discharging electrode socket (100) is large and a lot of discharging electrode sockets (100) are attached as in figure 9, the amount of air flown out through the discharging electrode socket (100) is large compared to the amount of air flown in the air chamber (55), and the pressure in the air chamber (55) becomes low. However, if the nozzle (10) in the discharging electrode socket (100) is small enough, the amount of air flown out is small compared to the amount of air flown in, and the pressure in the air chamber (55) is maintained uniformly.

1. Change of internal pressure in the air chamber and change of spouted amount of CDA according to the difference of the cross sectional area of the nozzle

We measured the change of pressure in the air chamber according to inputted

pressure in an apparatus having 17 discharging electrode sockets. 2 nozzles of 0.55mm in diameter are formed in each discharging electrode socket, and a CDA supplying means which can control the pressure arbitrarily is connected to the air chamber of the bar type ionizer through a polyurethane hose of 6mm in inside diameter. We checked the effect of decrease of used amount of CDA and the effect of preventing contamination of the discharging electrode by the increase of spouted pressure while variously changing the size of the cross sectional area of the nozzle, which this invention intends to propose.

< Comparative example 1 >

To check the efficiency of this invention, we formed 2 circular spouting nozzles of 0.51mm in average diameter regularly spaced in the direction of the axis of the discharging electrode in each of said 17 discharging electrode socket, and made CDA be spouted through the passage of 0.204mmf in average cross sectional area. Changing the pressure condition of CDA flowing into the air chamber in the range of 0.05-0.5 MPa while 17 CDA spouting nozzles are normally operated, we measured internal pressure in the air chamber and amount of used CDA for each condition. The result is shown in table 1.

[Table 1 ]

We can see that there is a great difference between input pressure and internal pressure in the air chamber under all normal operating condition, and spouting velocity is lowered because the internal pressure in the air chamber is low though large amount of CDA is spouted through the nozzle.

< Embodiment 1 >

As we can see from the result of comparative example 1, the size of the nozzle spouting ionized CDA should be small to operate bar type ionizer effectively. However, the nozzle (10') in previous air spouting socket was installed completely separated from the discharging electrode (20') (See figure Ic), or the nozzle (10') having structure of hexagon or circle surrounded the whole discharging electrode (20') even when the nozzle was contacted with the discharging electrode. (See figure Ie.) Accordingly, air did not flow around the discharging electrode and particles were easily stuck on the end of the discharging electrode, hi order to prevent adhesion of dust or particle on the discharging electrode by reducing the amount of CDA used and increasing the spouting velocity, cross sectional area of the nozzle should be minimized. However, decreasing

the cross sectional area is difficult in the previous nozzle shape. Above all, in case that the nozzle surrounds the discharging electrode, if the cross sectional area of the nozzle (10') is decreased, contacting area of CDA in the direction of axis is increased compared to the cross sectional area that the CDA passes, and accordingly the velocity cannot be increased though the spouted amount is small because of the friction loss.

To solve this problem, this invention uses a discharging electrode socket having nozzles facing each other on the end of the socket hole (15), and provided parallel to the axis of the discharging electrode (20), and formed as 0.16mm square as shown in figure Ia and figure Ib. Result of the test after setting each cross sectional area of the passage as 0.025mnf in average and setting other conditions as the same with comparative example 1 is shown in table 2. [Table 2]

We can see that internal pressure is not different from the input pressure, and the amount of CDA used becomes very small compared to comparative example 1.

< Embodiment 2 >

An air spouting socket having nozzles of 0.21mm square is used under the same condition with embodiment 1.

< Embodiment 3 >

An air spouting socket having nozzles of 0.26mm square is used under the same condition with embodiment 1. Result of the test is shown in table 3, table 4, figure 2, and figure 3. Table 3 shows internal pressure in the air chamber according to the input pressure and table 4 shows amount of spouted CDA according to the internal pressure in the air chamber. [Table 3]

We can see from the result that if the cross sectional area of the nozzle is increased the amount of CDA used is also increased, and internal pressure in the bar is decreased compared to the input pressure.

2. Change of internal pressure and amount of CDA according to the difference of the shape of nozzle

< Embodiment 4 >

In order to check ionized air spouting effect according to the geometric structure of the nozzle in this invention, we designed several nozzles having the same cross sectional area but different shapes and checked their efficiency. We made the cross section to be a triangle, square, or semicircle, and average cross sectional area to be

0.044mnf for each case and tested. The result was that if the cross sectional areas are the same regardless of the shapes, they have similar efficiency.

3. Change of neutralization efficiency according to the difference of the cross sectional area of nozzle

We compared neutralization efficiency according to the difference of the cross sectional area of spouting nozzle in the discharging electrode socket using a bar type ionizer having 30 discharging electrode sockets when neutralization distance between the discharging electrode socket and a charged object is constant(600mm, 1000mm). The neutralization efficiency is expressed as residual voltage of a charged object after the electrostatic charge is removed for the same time by ionized CDA spouted from the discharging electrode socket.

We set the CDA input pressure as 0.3 MPa and used the same discharging electrode socket that used in embodiment 1, 2, 3. We operated the bar type ionizer continuously after supplying CDA to the air chamber to increase reliability of residual voltage and recorded the residual voltage of the charged object after 72 hours and 360 hours for each test. [Table 5]

[Table 6]

Table 5 is the result of the neutralization efficiency test after operating 72 hours (3 days), and table 6 is after 360 hours (15 days). Table 5 shows the neutralization eff ⁱ ciency of the discharging electrode socket after 72 hours according to the comparison of residual voltage, and table 6 shows after 360 hours.

We can see from table 5 that compared to the previous discharging electrode in which circular nozzle of 0.55mm in diameter is formed, when the discharging electrode having square nozzle of 0.16mm in this invention is used, the residual voltage is similar at neutralization distance 600mm but neutralization efficiency is low at neutralization distance 1000mm. However, when square nozzle of 0.21mm or 0.26mm is used, the residual voltage is low compared to the previous discharging electrode though the amount of ionized CDA spouted from the nozzle is small, which means the neutralization efficiency is greatly improved. However, we cannot say the amount of CDA used should be necessarily minimized in order to increase the efficiency of the electrostatic eliminator from the test using square nozzle of 0.16mm, which means selecting optimized condition considering amount of CDA used, neutralization distance

between spouting nozzle and charged object, residual voltage of charged object is important.

Table 6 is the result after 15 days operation and we can see the electrostatic charge in the charged object is increased quickly compared to after 3 days operation when previous discharging electrode is used. The reason is that since the previous discharging electrode spouts large amount of CDA in low voltage, as the used time becomes longer the discharging electrode tip is contaminated by particles and the amount of ions generated becomes small. Meanwhile, when the discharging electrode socket (100) in this invention is used, the residual voltage after 15 days is not so different from the residual voltage after 3 days. The reason is that spouting CDA at high velocity is possible since input pressure in the air chamber is not decreased though CDA is spouted when the cross sectional area of the spouting nozzle (10) is reduced, and the discharging electrode (20) is not contaminated for a long time since the spouting nozzle has spouting angle parallel to the axis of the discharging electrode. The improved effect of protecting the discharging electrode from contamination in this invention can be confirmed by comparing the previous discharging electrode with the discharging electrode in this invention after operation for 360 hours as shown in figure 5 and figure

6.

Figure 4 presents a test environment of change of neutralizing efficiency according to the cross sectional area of the nozzle. 40 in figure 4 is CPM (charged plate monitor). In this test, we measured neutralizing efficiency by the CPM (40) installed dl (600mm) apart under the center of the bar type ionizer (50) to which the discharging electrode socket is attached (central part), d2(740mm) apart on the left and right of the central part, dl (600mm) apart under the central part, and d2(740mm) apart on the left and right of this part, which are the positions of charged object.

This invention may be modified and embodied in various forms, and it has been described and illustrated herein with reference to a specific embodiment thereof. However, it should be understood that this invention is not limited to the particular form as described above, and that this invention includes all modifications, equivalents and substitutes within the spirits and scope of this invention as defined in the "claims" attached hereto.