JPS637095B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power supply device for an electrostatic ultra-high performance filter used primarily to purify indoor air.

A filter called a HEPA filter is
Although they generally have high dust collection efficiency, they also have a high pressure loss when passing dust-containing gas through them.

Therefore, if you make the filter mesh coarser in an attempt to reduce pressure loss, the dust collection efficiency will decrease, and if you try to reduce the pressure loss by slowing down the ventilation speed, the filter will become larger. Ta. Another disadvantage was that the pressure loss due to clogging increased significantly and the life of the filter was short. For this reason, a method has been adopted in which a suitable pre-filter is provided in front of the filter to extend the life of the filter.

The present inventor arranged and fixed grounded parallel plate electrodes 2 in parallel in the airflow direction on a container frame 1 through which dust-containing gas passes, as shown in FIGS. 1 and 2, and each electrode 2
A charging section 4 consisting of a discharge wire 3 that applies a high voltage is stretched within an interval of A conductive separator (also known as a spacer) 7 is arranged in a meandering direction in the direction of the air flow, and conductive separators (also known as spacers) 7 that allow the passage of dust-containing gas between adjacent parts of the filter material are inserted from the upstream and downstream sides of the air flow, respectively.
It consists of a dust collection section 8 that applies a high voltage between each separator on the upstream side and each separator on the downstream side, and the dust particles precharged by the charging section 4 are collected in the dust collection section 8.
This is an electrostatic ultra-high performance filter that has a long lifespan and has an extremely high dust collection efficiency that can improve the dust collection efficiency by three orders of magnitude compared to the conventional filter material alone. Invented.

In this electrostatic ultra-high performance filter, if power is supplied directly to each separator on the upstream side and each separator on the downstream side, even if a discharge occurs in one separator, the charge in all separators will move to the discharge point. , because the discharge energy increases, the separator voltage temporarily decreases due to the discharge, and the dust collection efficiency temporarily decreases.
There is a risk of damage to the filter material such as holes being formed in the filter material.

The present invention aims to provide a power supply device for an electrostatic ultra-high performance filter that can solve the above problems.

Embodiments of the present invention will be described below based on FIGS. 3 to 12. FIGS.
In the figure, reference numeral 9 denotes a container frame through which dust-containing gas passes, and is composed of left and right side walls 10, 11, a top plate 12, and a bottom plate 13. Reference numeral 14 denotes a filter material made of glass fiber or the like, which snakes inside the container frame 9 from one side wall 10 to the other side wall 11, and has upper and lower ends connected to the top plate 12.
and the inner surface of the bottom plate 13. Reference numerals 15 and 16 denote filtering materials 14 that meander from the upstream and downstream sides of the airflow of dust-containing gas passing through the container frame 9.
A conductive separator sandwiched between adjacent parts of the filtration material 14, made of aluminum foil or the like, supports the adjacent parts of the filter material 14 so as to keep a constant distance between them, and also prevents dust-containing gas from entering the same space. It is bent into a wave shape from the top end to the bottom end to allow for easy passage. Reference numeral 17 denotes a surrounding wall that protrudes from the inner surface of the top plate 12 to surround the upper ends of the filter material 14 and the separators 15 and 16, and reference numeral 18 indicates a surrounding wall that surrounds the upper ends of the filter material 14 and the separators 15 and 16 from the inner surface of the bottom plate 13. A sealing material 19 is poured into these surrounding walls 17 and 18 and solidified using surrounding walls that protrude so as to bend, and both upper and lower end surfaces of the filter material 14 and separators 15 and 16 are airtightly connected to the top plate 12 and the bottom plate 13. It has been done. 20 and 21 are inserted along the gaps formed between each upstream separator 15 and the surrounding wall 18 and between each downstream separator 16 and the surrounding wall 18 before pouring the sealing material 19 into the sealing material 19. It is a conductive rubber sheet fixed by pouring, and has an electric resistance that prevents the movement of charges in each separator 15, 16, and these are made of a long and thin rubber sheet with its center line as a boundary, as shown in the fourth figure. The separators 15, 23 are bent in a V shape and biased so that the edges of both bent pieces 22, 23 are always open.
A bent piece 22 opposite to the bent piece 16 is provided with a thin cut piece 25 by making a number of cut lines 24 from its edge,
Individual strips 25 are separated by individual separators 15,1
6. 26 is a wire mesh or other porous cover attached to cover the entrance of the container frame 9; 27 is a porous cover 26 on the inside of the container frame 9;
A grounded parallel plate electrode is provided between the filter member 14 and the filter material 14, and is arranged in parallel in the same direction as the airflow of the dust-containing gas. 28 is a cylindrical conductive spacer that maintains the distance between each electrode 27 and makes each electrode 27 electrically conductive;
These are supported by a core rod 29 that penetrates each electrode 27 at three locations: the top, middle, and bottom. Reference numeral 30 denotes an ionization line provided at each interval between the electrodes 27, and a spring 3 is provided between the top plate 12 and the bottom plate 13.
1 and 32. 33 is a connection terminal for applying the high voltage of the high voltage power supply 34 to the conductive rubber sheet 21; 35 is a connection terminal for applying the high voltage of the high voltage power supply 34 to the ionization wire 30; 36 is a ground terminal; It is electrically connected to the upstream separator 15 that is in contact with the inner surface of the side wall 11 of the container frame 9, the conductive rubber sheet 20, and the aluminum foil 37 that is in common contact with the electrode 27. Reference numerals 38 denote the downstream side end surfaces of the left and right end surfaces of the filter material 14 and the left and right side walls 1 of the container frame 9.
If the left and right walls 10, 11 are made of a material that may generate dust, such as wood, the downstream side of the left and right walls 10, 11 is It also acts as a seal to prevent dust from forming on the inner surface of the side.

In the above configuration, the dust collection section formed by the filter material 14 and the separators 15 and 16 has a capacitor formed between the upstream separator 15 and the downstream separator 16, and the conductive rubber sheets 20 and 21. A high voltage is supplied through the electrical resistance, and a small amount of leakage current flows through the filter material 14, so the capacitance between each separator is reduced.
C ₁ , C ₂ , ......, _Co and conductive rubber sheet 2
Assuming that the resistances of 0 and 21 are R ₁ , R ₂ ......, _Ro , and the resistances of the filter material 14 are Rl ₁ , Rl ₂ , ......, Rl _o , the equivalent circuit of the dust collecting section is shown in Figure 7. It becomes as shown in .

Now, if we show the equivalent circuit when power is directly supplied to each separator 15, 16 without going through the conductive rubber sheets 20, 21, it will be as shown in Figure 8. , all the charges on each separator 15, 16 are instantaneously moved to the discharge location, and the discharge energy becomes large. The discharge energy at that time is approximately E ₁ = 1/2 (C ₁ +C ₂ + +C _o )V ² .

This discharge energy is transmitted through the separators 15, 1
6 and the applied voltage, and is not affected by the externally connected resistor _Rx .

However, as shown in Figure 7, separators 15 and 16
If power is supplied through the resistors R ₁ to _{R o} of the conductive rubber sheet one by one, even if a discharge occurs at one location on a certain separator, the discharged charge will be suppressed by the resistors R ₁ to R _o . Since the amount of charge is limited and the charge charged between other separators does not move to the discharge point, the discharge energy is approximately 1/n compared to the case not via the resistors R ₁ to _{R o} , that is, E ₂ = 1/2C _o V ² =E ₁ /n.

The external dimensions of the container frame 9 are, for example, 610 mm both vertically and horizontally, and 150 mm deep, the power supply voltage is 1 KV, the filter material leak resistance is 200 MΩ, the filter material leak current is 5 μA per separator stage, and the capacitance between separators is 3
In the case of ×10 ^-8 F, experiments have shown that the effect of limiting the discharge load becomes apparent when the value of the resistance _Ro becomes 10KΩ or more, although it depends on the capacitance between the separators. , the higher the resistance value, the smaller the charge transfer between the separators. However, resistance
If the value of R _o is set too large, a voltage drop will occur across the resistor R _o due to leakage current, and the voltage applied across the separator will essentially decrease.
Collection efficiency will decrease. As a specific example, if a voltage drop of 5% is allowed for the power supply voltage of 1KV, the leakage current is 5μA per spacer stage as mentioned above, so 1000×0.05/5×10 ^-6 = 10 ⁷ (Ω) Approximately 10MΩ or less If so, the voltage drop across the resistor R _o can be ignored.

Therefore, in the above experimental example, the range of resistance R _o is 10KΩ
It is appropriate to set it in the range of ~10 MΩ.

Next, to explain the action of the electrostatic ultra-high performance filter consisting of the above configuration, the ionization line 3
When a dust-containing gas is fed from the inlet of the container frame 9 with a DC high voltage applied to the separator 15 and
Gas containing charged particles 47 that are charged by corona discharge while passing through the charged part formed by the ionized wires 30 and ionized lines 30 passes through the dust collection part as shown by the dotted arrow in FIG. In the process, most of the charged particles 47 first reach each separator 1 on the upstream side.
5, adheres to the surface of each separator 15, and is removed. This effect is more pronounced as the charged particles have a larger particle size. Next, the gas flow 48 containing the remaining charged particles 47 passes through the filter material 14 in the shortest distance since the pressure loss through the filter material 14 is very large. For this reason, the airflow 48 is substantially parallel to and in the opposite direction to the electric lines of force 49 directed from the separators 16 to 15, as shown in Figure 10. At the same time, when the airflow 48 passes through the filter material 14, the speed of the airflow 48 becomes extremely slow compared to the speed (surface wind speed) upstream of the dust collecting section. In this way, when the direction of the electric field and the direction of the airflow are reversed, the electrical movement speed of the charged particles 47, that is, the movement speed in the direction of the electric lines of force 49, becomes greater than the speed of the airflow 48 passing through the filter material 14. Therefore, charged particles 47
cannot enter inside the filter material 144. On the other hand, since the airflow velocity through the filter material 14 is high, the charged particles 47 end up depositing on the surface of the filter material 14 in a porous manner. Next, filtering material 1 without being deposited in a porous manner
The charged particles 47 that have entered the filter material 14 move along the lines of electric force that gather on the fibers of the filter material 14 due to the electric field applied between the separators 15 and 16, so the area that can be captured by the fibers increases dramatically. do.

Due to the above dust collection mechanism, the dust collection efficiency is significantly increased, and clean gas flows out from the outlet of the container frame 9. Furthermore, the larger the particle size of the charged particles, the greater the effect of collecting them in each separator 15, which reduces clogging inside the filter material and significantly extends the service life.

In the above embodiment, the conductive rubber sheets 20, 21
Since a rubber sheet with a large number of thin pieces 25 provided thereon is used, even if the separators 15 on the upstream side or the separators 16 on the downstream side are sandwiched somewhat irregularly, the individual thin pieces 25 can be inserted into the individual separators. Since the pressure contact is made, there is an advantage that no contact failure occurs. However, in the case where each separator on the upstream side or each separator on the downstream side is accurately aligned and sandwiched, the present invention does not provide a thin section and is simply V. A conductive rubber sheet bent into a letter shape can be used.

The present invention is not limited to the above embodiments, and for example, as shown in FIG.
A conductive sealing layer 39 and an insulating sealing layer 40 having electrical resistance to prevent the movement of electric charges of the separators 15 and 16 are provided on the inner surface of the bottom plate 13, and the inner surface of the bottom plate 13 is also provided with a conductive sealing layer 39 having electrical resistance and an insulating material sealing layer 40 having the above-mentioned electrical resistance. A solid seal layer 41 and an insulating seal layer 42 are provided in two layers,
Each conductive separator 15 sandwiched between the meandering filter material 14 from the upstream side of the airflow has its upper end embedded in the conductive sealing layer 39 and its lower end embedded in the insulating sealing layer 42, so that it Conductive separators 16 sandwiched from the sides
The lower end is buried in the conductive seal layer 41 and the upper end is buried in the insulating seal layer 40, so that each separator 15 on the upstream side is electrically connected to only one conductive seal, and each separator 15 on the downstream side is electrically connected to only one conductive seal. The separator 16 is electrically connected only to the other conductive seal, and a negative or positive high voltage is applied to each separator 15 on the upstream side, and a positive or negative high voltage is applied to each separator 16 on the downstream side. It may also be configured as

In this case, since the liquid conductive sealing material is poured into the edges of each separator 15, 16 and hardened, power can be reliably supplied without being affected by the edge shape of each separator 15, 16, and reliability is high.

Also, as shown in Figure 12, separators 15 and 16 are provided on the inner surface of the top plate 12 and the inner surface of the bottom plate 13 of the container frame 9.
Rubber sheets 43 and 44 having electrical resistance to prevent the movement of charges are bonded together, and a contact piece formed on the upper end of each conductive separator 15 sandwiched between the meandering filter material 14 from the upstream side of the airflow is attached to the rubber sheet 43. A contact piece formed at the lower end of each conductive separator 16 sandwiched from the downstream side of the airflow is brought into elastic contact with the rubber sheet 44,
A negative or positive high voltage may be applied to each separator 15 on the upstream side, and a positive or negative high voltage may be applied to each separator 16 on the downstream side. In Fig. 12, 45 and 46 are filter material 1
4 and the upper and lower ends of each of the separators 15 and 16 are hermetically coupled to the top plate 12 and the bottom plate 13.

In this case, since each contact piece and the conductive rubber sheet come into contact with each other with appropriate pressure, the reliability of the contact is high.

In the above embodiment, an example was shown in which the charging section and the dust collecting section were provided in an integrally molded container frame, but it is also possible to provide both in separately molded container frames and to combine the container frames. There is also.

The present invention has the above-mentioned configuration, and connects each upstream separator and each downstream separator sandwiched between the meandering filter material to a high-voltage power supply device through a conductive material having an electrical resistance that prevents the movement of electric charges in each separator. can be connected, so if a discharge occurs at one location on a separator, the amount of discharge is limited by the electrical resistance, and it is possible to prevent all of the separator's charges from moving to the discharge location. Energy can be kept small. Therefore, the separator voltage does not temporarily decrease due to discharge, and therefore the dust collection efficiency does not decrease temporarily. Further, there is no risk of damaging the filter material such as making holes in the filter material. Also, since the conductive material is connected in a series like a conductive rubber sheet or a conductive seal, it is inevitable that each separator on the upstream side and each separator on the downstream side may be inserted unevenly between the filter materials. Regardless, it is possible to provide a power supply device which has advantages such as being able to easily bring the conductive material into contact with all of them without causing contact failure, and being easy to assemble.

[Brief explanation of the drawing]

Figure 1 is a perspective view schematically showing a conventional electrostatic ultra-high performance filter, Figure 2 is a circuit diagram of the filter,
FIG. 3 is a partially omitted perspective view of the device of the present invention, FIG. 4 is a perspective view showing an example of a conductive material, FIG. 5 is a vertical sectional view of the device of the present invention with some portions omitted, and FIG. A partially omitted cross-sectional view of the device of the present invention, FIG. 7 is an equivalent circuit diagram of the device of the present invention, FIG. 8 is an equivalent circuit diagram of the conventional device, and FIG. 9 is a diagram of the dust-containing gas passing through the dust collection section. A schematic diagram of airflow; FIG. 10 is a diagram explaining the relationship between the direction of movement of charged particles when passing through a filter material and the direction of the electric field; FIG. 11 is a diagram showing another embodiment of the present invention; FIG. 12 is a diagram showing the present invention. It is a figure which shows yet another Example of. 9... Container frame, 14... Filter material, 15... Upstream conductive separator, 16... Downstream conductive separator, 20, 21... Conductive rubber sheet, 25
... Thin section, 26 ... Porous cover, 27 ... Ground parallel plate electrode, 30 ... Ionization wire, 33 ... Connection terminal, 34 ... High voltage power supply device, 35 ... Connection terminal, 36 ... Earth terminal.

Claims (1)

[Scope of Claims] 1. A charging section that charges dust particles by corona discharge through the passage of dust-containing gas, and a filter material meandering in a direction perpendicular to the airflow direction of the dust-containing gas passing through the charging section. Conductive separators bent into waveforms are sandwiched between adjacent parts of the filter material from the upstream and downstream sides of the airflow, and each separator on the upstream side and each separator on the downstream side are sandwiched between adjacent parts of the filter material. In an electrostatic ultra-high performance filter consisting of a separator and a dust collector that applies a high voltage between them, each separator on the upstream side has an electrical resistance that prevents the movement of charge, and is a series of conductive materials. is arranged so as to be in contact with all of the separators on the upstream side, and has an electrical resistance that prevents the movement of charge in each separator on the downstream side, and a series of conductive materials is placed in contact with all of the separators on the downstream side. A power supply device for an electrostatic ultra-high performance filter, comprising: a high-voltage power supply device connected to each conductive material; 2. A conductive rubber sheet whose conductive material has an electrical resistance that prevents the movement of charges in each separator is bent into a V shape, and a number of score lines are inserted from one edge of the bent piece to form a number of thin pieces. A power supply device for an electrostatic ultra-high performance filter according to claim 1, comprising a contact piece. 3. The conductive material is a liquid conductive sealing material having an electrical resistance that prevents the movement of charges in each separator, and the end of the meandering filter material and the end of each upstream separator sandwiched between the filter material are connected to each other. A conductive seal poured and solidified into the area in contact with the frame, and the conductive sealing material are applied to the area where the end of the filtration material and the end of each downstream separator sandwiched between the filtration materials contact the vessel frame. A power supply device for an electrostatic ultra-high performance filter according to claim 1, comprising a pair of conductive seals that are poured and solidified. 4. The power supply device for an electrostatic ultra-high performance filter according to claim 3, wherein a pair of conductive seals are provided on opposing wall surfaces of the container frame. 5. A conductive rubber sheet with electrical resistance that prevents the movement of charges in each separator is sandwiched between the meandering filter materials so that the contact pieces provided at the ends of each upstream separator come into elastic contact with each other. A pair of conductive sheets provided in such a manner that the conductive rubber sheet is in elastic contact with the contact piece provided at the end of each downstream separator sandwiched between the filter material. A power supply device for an electrostatic ultra-high performance filter according to claim 1, which comprises a conductive sheet. 6 Claim 5, wherein a pair of conductive sheets are provided on opposing wall surfaces of the container frame, respectively.
Power supply device for the electrostatic ultra-high performance filter described in Section 1.