OZONE CHEMISTRY AND TECHNOLOGY

Electrical Characteristics of the Ozonizer SACHIO FUJI and

NAOSHI

TAKEMURA

OZONE CHEMISTRY AND TECHNOLOGY Downloaded from pubs.acs.org by UNIV OF CALIFORNIA SAN DIEGO on 12/27/16. For personal use only.

Electrotechnical Laboratory, Ministry of International Trade and Industry, Tokyo, Japan

Extensive studies (1, 4) have been made on the chemi cal reaction involved in silent electric discharge. Also, studies have been undertaken to explain the characteristics of silent electric discharge purely on the basis of electrotechniques (2, 3, 5, 6). The a u thors have studied the electrical characteristics of a n ozonizer to find relations between the gaseous reac tion occurring in the silent discharge a n d the electri cal conditions governing it.

T h e c h e m i c a l r e a c t i o n a n d t h e e l e c t r i c a l c h a r a c t e r i s t i c s of s i l e n t electric d i s c h a r g e h a v e b e e n c o r r e l a t e d b y s t u d i e s o n a n o z o n i z e r . U s u a l l y , t h e s p a c e i n s i l e n t d i s c h a r g e is t e r m i n a t e d b y d i e l e c t r i c s w h i c h a c t as t h e s t a b i l i z i n g resistance w i t h a l i t t l e loss a n d p r e v e n t c o n c e n t r a t i o n of t h e d i s c h a r g e . A n a l t e r n a t i n g c u r r e n t m u s t b e u s e d . Experimental

Equipment

and

Conditions

T h e s i l e n t d i s c h a r g e t u b e is a c y l i n d r i c a l t u b e of h a r d glass. T h e c o n s t r u c t i o n a n d d i m e n s i o n s a r e g i v e n i n F i g u r e 1. T h e a i r g a p a n d t h i c k n e s s of t h e glass t u b e a r e

I

42.21

,Cu ELECTRODE

Τ7Ά πττλ Vtrnf/n ÏÏ7T 260

ELECTROLYTICSOLUTION

Figure 1.

185mm.

Silent discharge 334

tube

335

FUJI A N D TAKEMURA—ELECTRICAL CHARACTERISTICS OF OZONIZER

1.6 a n d 1.4 m m . , r e s p e c t i v e l y . B o t h i n s i d e a n d o u t s i d e t h i s d o u b l e glass t u b e t h e r e is a n e l e c t r o l y t i c s o l u t i o n ( c o p p e r s u l f a t e s o l u t i o n ) w h i c h i s u s e d as t h e electrodes. T h e experiments were c a r r i e d out at atmospheric pressure. T h e a i r went t h r o u g h the d i s c h a r g e t u b e a t t h e r a t e of 0 t o 5.5 l i t e r s p e r m i n u t e , a n d a 10,000-volt a l t e r n a t i n g c u r r e n t w a s a p p l i e d across t h e electrodes. A s t h e discharge was sometimes u n s t a b l e a n d l o c a l l y c o n c e n t r a t e d i m m e d i a t e l y a f t e r a p p l i c a t i o n of t h e v o l t a g e , m e a s u r e m e n t s w e r e b e g u n a f t e r t h e d i s c h a r g e s p r e a d u n i f o r m l y t h r o u g h o u t t h e a i r g a p of t h e discharge tube. T h e m e a s u r i n g c i r c u i t is s h o w n i n F i g u r e 2. A condenser, C , i s i n s e r t e d t o r e m o v e influences r e s u l t i n g f r o m t h e i m p e d a n c e of t h e e l e c t r i c p o w e r source. R i s a s h u n t resistance u s e d t o m e a s u r e t h e c u r r e n t w a v e f o r m . T h e v o l t a g e w a v e f o r m w a s measured b y a cathode-ray potential divider.


P

rr-JOSO

T777T

Figure 2 .

Measuring circuit

T o o b s e r v e t h e w h o l e w a v e f o r m , a n o r d i n a r y c a t h o d e - r a y oscilloscope, o p e r a t e d w i t h t h e s a w - t o o t h t i m e base, w a s u s e d . A single sweep c a t h o d e - r a y oscilloscope, w h i c h c o u l d s t a r t s w e e p i n g a t a n y d e s i r e d p h a s e of t h e a p p l i e d v o l t a g e , w a s u s e d t o m e a s u r e t h e d e t a i l s of a d e s i r e d p a r t of t h e c u r r e n t w a v e f o r m . C h a r a c t e r o f the

Discharge

T h e d i s c h a r g e a p p e a r s t o o c c u r as t h o u g h i n n u m e r a b l e fine t h r e a d s were s t r e t c h e d i n t h e d i s c h a r g e s p a c e of t h e t u b e . T h e c u r r e n t w a v e f o r m w a s o b s e r v e d w i t h t h e o r d i n a r y c a t h o d e - r a y oscilloscope. T h e f u n d a m e n t a l w a v e leads t h e v o l t a g e w a v e b y a b o u t 9 0 ° as s h o w n i n F i g u r e 3, a n d h i g h f r e q u e n c y p u l s a t i n g c u r r e n t s s u p e r p o s e

Current wave form

Applied voltage wave form

Figure 3.

Fundamental a n d voltage wave of discharge A. R = 172 Κ Ω

B. R = 50 Κ Ω

o n t h e f u n d a m e n t a l one n e a r t h e k n o b ( a t m a x i m u m of c u r r e n t w a v e f o r m as s h o w n i n F i g u r e 3, A). T h u s , t h e d i s c h a r g e consists of i n n u m e r a b l e l o c a l ones. T o o b s e r v e these h i g h f r e q u e n c y l o c a l discharges i n d e t a i l , t h e single sweep c a t h o d e - r a y oscilloscope i s u s e d . F i g u r e 4 shows a n e x a m p l e of t h e o s c i l l o g r a m s o b t a i n e d : A n i n d i v i d u a l p u l s a t i n g c u r r e n t is a n i m p u l s i v e w a v e t h a t recedes e x p o n e n t i a l l y , a n d t h e t a i l l e n g t h of t h e w a v e depends o n t h e resistance, R, i n s e r t e d i n t h e c i r c u i t t o m e a s u r e t h e c u r r e n t . I n c r e a s e i n the v a l u e of R r e s u l t s i n a n increase i n t a i l l e n g t h . I n s e r t i n g a n i n d u c t a n c e c o i l i n s t e a d of t h e resistance, t h e a u t h o r s m e a s u r e d t h e t e r m i n a l v o l t a g e of t h e c o i l a n d o b t a i n e d r e p e a t i n g h i g h f r e q u e n c y d a m p e d o s c i l l a t i o n s as s h o w n i n F i g u r e 5.

336

A D V A N C E S IN CHEMISTRY SERIES

CURRENT WAVE FORM OF THE SILENT DISCHARGE


Figure 4.

Oscillogram by single sweep oscilloscope

Figure 5. Terminal volt a g e of the inductance coil instead of the resistance M e a s u r e m e n t s of t h e f r e q u e n c y of t h e o s c i l l a t i o n i n d i c a t e d t h a t t h e decrease i n i n d u c t a n c e r e s u l t e d i n t h e increase i n f r e q u e n c y . A s these p h e n o m e n a a r e s i m i l a r t o t h e d i s c h a r g e of a condenser c h a r g e t h r o u g h t h e resistance o r t h e i n d u c t a n c e , t h e c a p a c i t y of t h e condenser w a s e v a l u a t e d f r o m t h e v a l u e s of t h e resistance, t h e t a i l l e n g t h , a n d t h e i n d u c t a n c e t o b e a b o u t 200 μμΐ., i r r e s p e c t i v e of t h e v a l u e s of t h e resistance a n d t h e i n d u c t a n c e . F i g u r e 6 shows t h e o s c i l l o g r a m w h i c h w a s p h o t o g r a p h e d b y t h e r a p i d t i m e sweep to s t u d y t h e d e t a i l s of t h e w a v e f r o n t of t h e w a v e f o r m s h o w n i n F i g u r e 4. S e v e r a l

Figure 6. Current wave form of discharge; tim ing, 500 kc. steps a r e o b s e r v e d a t t h e w a v e f r o n t ; these i n d i c a t e t h a t t h e discharges of v e r y steep f r o n t w a v e s o c c u r successively a t s u c h s h o r t t i m e i n t e r v a l s as a b o u t 0.2 t o 0.3 /^second. T h i s w a v e h a s a n a p p e a r a n c e of a single p u l s a t i o n w h e n o b s e r v e d u s i n g t h e s l o w t i m e sweep. F r o m F i g u r e 6, i t seems t h a t one d i s c h a r g e i n i t i a t e s successive d i s c h a r g e s i n t h e n e i g h b o r i n g space. H e n c e , one p u l s a t i o n does n o t c o r r e s p o n d t o a single d i s c h a r g e , b u t t o a series of d i s c h a r g e s . F r o m these c o n s i d e r a t i o n s o n t h e l o c a l discharges, t h e e q u i v a l e n t c i r c u i t f o r a single d i s c h a r g e is p r o p o s e d i n F i g u r e 7, w h e r e C a n d C c o r r e s p o n d t o t h e c a p a c i t i e s of t h e a i r g a p a n d glass of t h e d i s c h a r g e t u b e p e r u n i t a r e a , C i s t h e s t r a y c a p a c i t y of t h e vessel t o t h e e a r t h , a n d C is t h e c a p a c i t y of p o r t i o n s w h e r e t h e a i r g a p b e c o m e s so w i d e t h a t t h e d i s c h a r g e does n o t o c c u r . A s s u m i n g t h a t t h e t o t a l d i s c h a r g e a r e a of t h e t u b e is S, t h e c a p a c i t y , C , b e t w e e n t h e electrodes of t h e d i s c h a r g e t u b e is a

g

s

0

C = CaCgS/(Ca + C ) + ( 0

(1)

T a b l e I s h o w s v a l u e s of these c a p a c i t i e s m e a s u r e d w i t h t h e c a p a c i t y m e t e r . A s s u m i n g i n this equivalent circuit t h a t the discharge occurs w h e n the a p p l i e d voltage

FUJI A N D

337

TAKEMURA—ELECTRICAL CHARACTERISTICS OF OZONIZER

DISCHARGE PART

C (S-*S ) 3

0

C (S-AS )


A

0

NON DISCHARGE PART

Figure 7.

Proposed

equivalent circuit for a charge T.

Table I.

single

dis

Transformer

Capacities Measured between Electrodes of Discharge Tube Measured Capacity, μμΐ. 0.77 3.1 15.0 115.0 90.0 1000.0 30000.0

Ca C Co C C. C d a

P

across t h e a i r g a p i n t h e d i s c h a r g e space reaches t h e b r e a k d o w n v o l t a g e , V , t h a t t h e d i s c h a r g e ceases w h e n t h e v o l t a g e recedes t o V , a n d t h a t t h e change i n a p p l i e d v o l t a g e d u r i n g t h e t i m e of a single d i s c h a r g e is n e g l i g i b l y s m a l l because t h e t i m e i n t e r v a l of t h e single d i s c h a r g e is v e r y s m a l l i n c o m p a r i s o n w i t h t h e i m p r e s s e d a l t e r n a t i n g c u r r e n t p e r i o d , t h e n t h e e q u i v a l e n t c i r c u i t f o r a single d i s c h a r g e i s as s h o w n i n F i g u r e 8. T h e resistance of t h e d i s c h a r g e p a t h a n d t h a t of t h e e l e c t r o l y t i c s o l u t i o n a r e o m i t t e d ; t h e y a r e n e g l i g i b l y s m a l l because t h e f r o n t of t h e i m p u l s i v e w a v e is v e r y steep. 8

d

(Vs-V )1 a

(^(S-AS,,)

osc'

C AS A

0

-r-C (S-aSo) a

"C AS 5

Figure 8.

Revised

e

equivalent circuit for a discharge

single

T h e authors evaluated the current at the instant the discharge occurred i n the c i r c u i t . I f Δ $ is t h e a r e a of a d i s c h a r g e space, t h e n 0

AS CaC /(C + C ) 0

g

a

is n e g l i g i b l y s m a l l i n c o m p a r i s o n w i t h C, as Δ S expressed b y t h e f o l l o w i n g e q u a t i o n :

g

0

(Ca.+

QR

w h e r e t is t h e t i m e d u r a t i o n of t h e i m p u l s e .

is v e r y s m a l l .

T h e current, I , d

is

(2)


338

A s s h o w n i n T a b l e I , C a n d C a r e 115 a n d 90 μμΐ., r e s p e c t i v e l y ; hence, C + C — 205 μμΐ. T h i s v a l u e agrees w i t h t h e m e a s u r e d v a l u e , 2 0 0 μμί., w i t h i n e x p e r i m e n t a l error. T h e w a v e f o r m s p r o d u c e d w h e n t h e i n d u c t a n c e c o i l is i n s e r t e d are e x p l a i n e d b y t h i s e q u i v a l e n t c i r c u i t . T h e c u r r e n t f o r m of t h e d i s c h a r g e t u b e is e x p l a i n e d b y c o n s i d e r a t i o n s o n t h e l o c a l d i s c h a r g e s . A s s h o w n i n F i g u r e 3, A, n o p u l s a t i o n of c u r r e n t is o b s e r v e d i n a c e r t a i n r e g i o n of t h e h a l f c y c l e a f t e r t h e m a x i m u m v a l u e . I t i s c o n s i d e r e d t h a t t h e d i s c h a r g e does n o t o c c u r i n t h i s r e g i o n . I n a d e t a i l e d e x a m i n a t i o n i n t o a p a r t of t h e discharges, i t is a s s u m e d t h a t t h e d i s c h a r g e i n t h e a i r g a p o c c u r s w h e n t h e v o l t a g e across t h e a i r g a p reaches t h e s p a r k i n g p o t e n t i a l V a t t h e t i m e d e n o t e d b y p o i n t 1 i n F i g u r e 9 a n d t h a t t h e d i s c h a r g e ceases i n a v e r y s h o r t t i m e .


s

8

s

DISCHARGE PART

PART Figure 9. Details of discharge to deter mine rate of occurrence

T h e n t h e a p p l i e d v o l t a g e increases b y E — (1 + C /C ) (V — V ) a n d reaches p o i n t 2 i n F i g u r e 9. T h e v o l t a g e across t h e a i r g a p becomes V a g a i n , a n d t h e d i s c h a r g e o c c u r s . T h u s , w h e n t h e a p p l i e d v o l t a g e is h i g h e n o u g h , t h e discharges o c c u r one a f t e r a n o t h e r e v e r y t i m e t h e v o l t a g e increases b y E . I f t h e v o l t a g e across t h e a i r g a p does n o t rise h i g h e n o u g h f o r d i s c h a r g e e v e n a t t h e p e a k v a l u e of t h e a p p l i e d v o l t a g e , t h e n e x t d i s c h a r g e o c c u r s w h e n t h e v o l t a g e decreases a f t e r p a s s i n g i t s m a x i m u m v a l u e . D u r i n g t h e f o l l o w i n g h a l f c y c l e , t h e v o l t a g e becomes l o w e r t h a n t h e l a s t d i s c h a r g e v o l t a g e , g i v e n b y p o i n t 2, b y E = (1 + C /C ) (V 4- V ). A s i m i l a r d i s c h a r g e t a k e s p l a c e i n t h e f o l l o w i n g h a l f c y c l e . H e n c e , t h e first d i s c h a r g e a f t e r t h e m a x i m u m of t h e v o l t a g e w a v e occurs w h e n t h e v o l t a g e decreases b y E f r o m t h e m a x i m u m v a l u e , a n d n o d i s c h a r g e occurs i n regions d e n o t e d b y f a t lines i n F i g u r e 9. T h i s e x p l a i n s w h y t h e o b s e r v e d w a v e f o r m h a s n o p u l s a t i o n i n these regions. T h e r e f o r e , E does n o t d e p e n d u p o n t h e a p p l i e d v o l t a g e u n d e r c e r t a i n o p e r a t i n g c o n d i t i o n s of t h e d i s c h a r g e t u b e . E x p e r i m e n t a l r e s u l t s also s h o w t h a t E does n o t c h a n g e w i t h t h e a p p l i e d v o l t a g e . I n t h e t u b e test, E = 12 k v . C o n s e q u e n t l y , Vs + V = 9.6 k v . i s o b t a i n e d . a

a

g

s

d

8

a

h

a

g

s

d

b

b

b

b

d

T h e r a t e of o c c u r r e n c e of t h e d i s c h a r g e w a s c o n s i d e r e d , t o o b t a i n t h e c u r r e n t i n t h e d i s c h a r g e p e r i o d . F r o m c o n s i d e r a t i o n s s i m i l a r t o those a b o v e , t h e d i s c h a r g e t a k e s p l a c e i n t h e a r e a Δ θ d u r i n g a change ΔΕ i n t h e a p p l i e d v o l t a g e w h e n t h e a p p l i e d v o l t a g e i s h i g h e r t h a n t h e p r e c e d i n g d i s c h a r g e b y E o r l o w e r b y E ; hence AS/ΔΕ is c o n s t a n t a t p o r t i o n s s h o w n as 1, 2, a n d 3 i n F i g u r e 10. A l t h o u g h Δβ/ΔΕ c a n n o t b e c o n s i d e r e d c o n s t a n t a t e v e r y p a r t of t h e a p p l i e d v o l t a g e , i t i s a c c e p t e d t h a t Δ&/ΔΕ is almost constant t h r o u g h o u t the whole discharge region. A c t u a l l y t h e d i s c h a r g e o c c u r s i n t e r m i t t e n t l y , a n d t h e a r e a of t h e d i s c h a r g e space increases b

a


FUJI A N D TAKEMURA—ELECTRICAL

CHARACTERISTICS OF OZONIZER

339

Figure 10. Details of discharge to determine current stepwise as s h o w n b y t h e s o l i d l i n e i n F i g u r e 11. B u t t h e a b o v e a s s u m p t i o n m e a n s t h a t t h e a r e a of d i s c h a r g e , S, increases l i n e a r l y w i t h Ε as s h o w n b y t h e b r o k e n l i n e , a n d t h a t dS/dE is c o n s t a n t . T h i s w a s v e r i f i e d b y e l e c t r i c a l p o w e r d i a g r a m s o b t a i n e d with the cathode-ray wattmeter. A s s u m i n g t h a t AS/ΔΕ is almost constant i n t h e whole discharge region, t h e a v e r a g e t e r m i n a l v o l t a g e o f t h e c o n d e n s e r is p r o p o r t i o n a l t o t h e a p p l i e d v o l t a g e ; i n f a c t , t h e t e r m i n a l v o l t a g e of t h e c o n d e n s e r increases s t e p w i s e . T h e p o w e r d i a g r a m s h o u l d h a v e a p a r a l l e l o g r a m i c f e a t u r e , because t h e slope of t h e d i a g r a m differs, depending o n whether discharge is t a k i n g place or n o t . T h e power d i a g r a m obtained e x p e r i m e n t a l l y is o n t h e w h o l e a p a r a l l e l o g r a m w i t h fine fluctuations i n t h e d i s c h a r g e region (Figure 12). T h e v a l u e of dS/dE w a s c o n s i d e r e d . I f t h e a p p l i e d v o l t a g e changes b y E , t h e w h o l e d i s c h a r g e space m u s t r e a c h t h e s p a r k i n g p o t e n t i a l once. A c c o r d i n g l y , t h e d i s c h a r g e also occurs once. H e n c e , dS/dE = S/E is o b t a i n e d , w h e r e S is t h e t o t a l discharge area. B y these r e l a t i o n s , t h e a u t h o r s e v a l u a t e d t h e a v e r a g e d i s c h a r g e c u r r e n t , I w h e n t h e v o l t a g e E sm t is a p p l i e d . W h e n (C + C)R«1, t h e effect of t h e a

a

dMt

m

w

8

TOTAL AREA OF ELECTRIC DISCHARGE

Figure 11.

A r e a of discharge space Actual Assumed


340


Figure 12.

Experimental

power diagram p r e c e d i n g h a l f w a v e is n e g l i g i b l e , a n d f r o m E q u a t i o n s 2 t o 4, E q u a t i o n 5 is o b t a i n e d .

dE/dt = o>E cos ωί

(3)

m

dS/dE = S/E = 5/(1 + Ca/C )(V - V ) a

g

L(Cs+ where

ωί = s i n 0

- 1

s

(E —

Χ e

cos ,r

X ^ # 7 7 7

C)R~

(4)

d

1 + Ca/Ct

"

^

^

(5)

e*r

E )/E

b

m

m

T h i s e q u a t i o n m e a n s t h a t t h e w a v e t a i l of e a c h d i s c h a r g e c u r r e n t i s s u p e r p o s e d on each other a n d the average current, I ,

goes t h r o u g h t h e d i s c h a r g e t u b e .

dm

E v a l u a t i n g E q u a t i o n 5, t h e a u t h o r s o b t a i n e d hm =

° f X ° = cos [a>t Ca + C V l + C0 (C., + C) R

n

œ C

n

-

e

E m

2

2

a

~(C«+Ofl '"' (

W h e n ( C + C)7^ < < a n d E q u a t i o n 6 becomes

cos [ω/ -

o )

tan-* u>(C + C)R] s

2

t a n " ω X (C + C)/2]

(6)

1

0

s

1, t h e e t e r m is n e g l i g i b l e e x c e p t w h e r e t is close t o

s

Idm Φ

r

f*

C

0

(7)

0}CgE COS œt

r

t,

m

T h e c u r r e n t t h r o u g h t h e d i s c h a r g e t u b e is t h e s u m of t h e a v e r a g e d i s c h a r g e c u r r e n t a n d t h e c h a r g i n g c u r r e n t , I , of t h e c a p a c i t y b e t w e e n t h e d i s c h a r g e t u b e a n d the lead wire, where c

œCE

=

m

c

o

g

[ ω ί

_

t a n

_

l w

(

c

( 8 )

V l + 2(Ο + cyR* ω

β

(9)

φ œCE COS m

T h e r e f o r e , t h e t o t a l c u r r e n t , / , is r e p r e s e n t e d b y I

c

φ wCE cos m

/ = I + Idm Φ o>(CVS + C )J& cos ωί c

0

to

in nondischarge region

(10)

in discharge region

(11)

I f t h e a v e r a g e v a l u e of t h e d i s c h a r g e c u r r e n t consists of t h e w a v e t a i l l e n g t h of each discharge current superposed o n each other, t h e f o r m of t h e k n o b a p p e a r i n g at t h e d i s c h a r g e p a r t of t h e c u r r e n t w a v e f o r m i n F i g u r e 3 is c a u s e d b y s u p e r p o s i t i o n of t h e w a v e t a i l s of i m p u l s e w a v e s . changes,

depending

B e c a u s e t h e w a v e t a i l l e n g t h of e a c h i m p u l s e w a v e

o n t h e v a l u e of i n s e r t e d r e s i s t a n c e , t h e f o r m

c h a n g e s a c c o r d i n g t o t h e v a l u e of t h e i n s e r t e d r e s i s t a n c e .

of t h e k n o b

also

I n fact, when the current

w a v e f o r m is o b s e r v e d w h i l e t h e v a l u e of t h e i n s e r t e d r e s i s t a n c e i s v a r i e d , t h e r e is a c h a n g e i n t h e f o r m of t h e p e a k as seen b y c o m p a r i n g F i g u r e 3, A, w i t h F i g u r e 3, B. T h e m e a n v a l u e , 7 , of t h e c u r r e n t t h r o u g h t h e d i s c h a r g e t u b e is o b t a i n e d as f o l l o w s : m


Ε = E /V2

= effective value of voltage

I

=

m

m

=~oCE

m

341


(12)

\V2fCE

(13)

where/ = frequency of electric source, and 2E

< Eb.

m

7Γ

OûCEm cos ù)t dt + ^


L 2 /ι

2E

m

>

0

0

(14)

2ω

o(C£ + C )£ + - (C f

0

w

CS -

(Ifi)

C )E

0

0

b

X

= 4V2/(C„-S + C„)B where

œ(C S + C )#m cos id d i j

2 ω

2fC S{V, + g

V)

(16)

d

E. h

lOOOr

5 APPLIED Figure 13.

10

V O L T A G E , Κ v.

Effect of applied mean current

voltage

on

Experimental Calculated

F i g u r e 13 s h o w s t h e r e l a t i o n of t h e m e a n c u r r e n t vs. t h e a p p l i e d v o l t a g e , b o t h t h e one o b t a i n e d e x p e r i m e n t a l l y a n d t h e one c a l c u l a t e d b y t h e a b o v e e q u a t i o n . T h e r e is good agreement between the t w o . F o r t h e p o w e r , P , d i s s i p a t e d i n t h e d i s c h a r g e t u b e , e v a l u a t i o n of t h e p o w e r f o r t h e d i s c h a r g e c u r r e n t o n l y is sufficient. H e n c e , Ρ = 0 where

2E

m

(17)

< E

b

ω /*2ω o>Cg SEm sin Jto C H~ Cg 2

2

œt X

cos

ω ί dt

a

= fC S(V, + V )[2V2 Ε B

where

2E

m

> Eb

a

(1 + Ca/Cg)(V + V )] a

d

(18)

342

A D V A N C E S IN

CHEMISTRY SERIES

T h e p o w e r is m e a s u r e d b y t h e c a t h o d e - r a y w a t t m e t e r m e t h o d . L e t t h e deflecting s e n s i b i l i t y of e a c h p a i r of d e f l e c t i o n p l a t e s be D and D , respectively; is the c a p a c i t y of t h e c u r r e n t c a l c u l a t i n g condenser, w h i c h is i n s e r t e d i n p l a c e of t h e resistance, R, t o m e a s u r e t h e c u r r e n t . T h e n t h e a r e a of t h e d i a g r a m , A, is g i v e n b y ±

A=f

'DtEdfâ (Ί-dt) Jt=o \Ci Jo )


= ^ -

2

2

= ^ Ci

2

[ EIdt Jt=o

(19)

f

P

(20)

a n d t h e e l e c t r i c p o w e r is g i v e n b y Ρ = CifA/DiD*

(21)

F i g u r e 14 shows t h e e l e c t r i c p o w e r , b o t h t h e e x p e r i m e n t a l a n d c a l c u l a t e d v a l u e s . T h e e l e c t r i c p o w e r increases i n p r o p o r t i o n t o t h e increase i n a p p l i e d v o l t a g e a f t e r

APPLIE0 Figure 14.

VOLTAOE,

KV.

Effect of applied voltage on elec tric power Experimental Calculated

t h e d i s c h a r g e begins, a n d t h e r e is g o o d a g r e e m e n t calculated values.

between

the

experimental and

Conclusion T h e c u r r e n t w a v e f o r m i n t h e s i l e n t d i s c h a r g e is e x p l a i n e d , a n d t h e v o l t a g e - c u r r e n t characteristics obtained show good agreement w i t h experimental results. F r o m these f a c t s , t h e v e r y h i g h f r e q u e n c y p u l s a t i o n is t h e basic p r o b l e m of t h e s i l e n t d i s c h a r g e . T h e a u t h o r s s u p p o s e t h a t t h e c h e m i c a l r e a c t i o n is affected b y t h e a v e r a g e v a l u e of t h e c u r r e n t . T o c l a r i f y f u r t h e r the relations between the silent discharge a n d chemical reac tions, the discharge starting voltage, V , i n the silent discharge a n d the extinguishing v o l t a g e , V , s h o u l d be m e a s u r e d . T h e w a v e f o r m a n d d e n s i t y of t h e c u r r e n t a l o n g t h e d i s c h a r g e p a t h also s h o u l d be e x a m i n e d . s

d

Literature

Cited

(1) Glockler, G., Lind, S. C., "Electrochemistry of Gases and Other Dielectrics," pp. 2955, Wiley, New York, 1939. (2) Klemenc, Α., Hintenberger, H., Höfer, Η., Z. Elektrochem. 4 3 , 708 (1937).



343

(3) Suzuki, M., Department of Chemistry, Tokyo Metropolitan University, unpublished data. (4) Thompson, M. de Κ., "Theoretical and Applied Electrochemistry," pp. 481-6, Maximil ian, London, 1939. (5) Warburg, Ε., Z. tech. Physik 4, 450 (1923). (6) Warburg, E., Leithäuser, G., Ann. phys. 2 8 , 1 (1909).


RECEIVED

for review M a y 27, 1958.

Accepted June 19, 1957.

OZONE CHEMISTRY AND TECHNOLOGY

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