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(1)Impact Vibration which takes place at the Opening of High Pressure Ball Valves (lst Report). ). By '. Fumie NOGUCHI (Received June 14, 1965). Abstract /Impact vibrations which occur at the instantaneous opening of ball valves under high pressure were observed by a syncro-oscillQscope.. These investigations were made under the alteration of valve port's diameter, lifted heights of ball valve, pressure, and the diameter of lifting rod.. It was made clear that the pressure amplitude is affected awfully by pressure change, but not by the lifted height of ball valves, and the period is affected by the diameter of valve port.. gl. Introducti'on. }. Author found out incidental!y that the liquid contained around a non-return valve vibrates by an impact which occurs at the opening of bal! valve under high pressure, and investigated its wave forms by a syncro-oscilloscope. The experimentation was carried out to see how the pressure amplitude' and the period of vibration wave form .is affected by the diverse alteration of the diameter of ball valve, consequently the inner diameter of valve port, of lifted height of ball valve, of the liquid pressure accumlated in the cavity beyond the none-return valve, and of the sectional area of the valve port. Some products were gained.. g2. Experimental apparatus and Procedures Fig. 1 shows in its central position the valve body, and' in it there fi11ed. brake liquid same as used by motor cars. In this valve body there is a steel ball valve which is pressed by a spring to its seat. This valve geat is made with an accurate finish, so that when the ball contact closely to it, there is no. liquid leakage. Now when the liquid is force-fed by a pump from the underside of this valve seat, the ball is lifted up and allows the passing of the liquid, but once when the force of feed is relaxed, the ball is forced to adhere. to its seat, and no liquid is allowed to flow backward. As the force pump of this liquid we used a automotive brake master-cylinder, and a jack is used to '. '.

(2) 36 ' F.NoGucHi '. press the piston by turning its screw handle. By some reciprocation of the piston, the liquid is filled up in the space over the ball valve. After ascertain-. ing that there is no residual air in any space, we may press the piston foreward by turning the screw handle, then the liquid is fi11ed up in whole space, and if there isi no leakage there, there happens a pressure ascension and it is. .. indicated on the Bourdon tube type pressure gauge on the right. When the pressure is attained to a required ameunt, the screw of jack should be turned backward, and the piston retreated. At this time as-the ball is pressed firmly. a. to its seat by the forces of liquid pressure and the spring and acts as a none-. return check valve, the liquid beyond the valve cannot fiow backward, and owing to the elasticity of tubes and joints containing the liquid, and if there is no leakage there, the pressure is maintained to its required amount.. As,there is a replenishing device on the master-cylinder used as a force pump, if the piston is made to retreat after the closing of ball valve, the space. onthissideofthevalveisalwaysfi11edwithliquid.. . When we turn on the switch shown right underneath in Fig. 1, the eiectric motor begins to rotate, and the cam disk fitted on its shaft lifts up the cam lever, and the plunger inserted in the valve body is then lifted up, and. consequently the rod attached on the tip of the plunger becomes to push up the ball valve, the function of ball valve as a nene-return valve is put to an end, and the liquid, but a few amount, flows back towards the pump, and the v. pressure accumlated beyond the valve makes a sudden depression. After the cam lever abovementioned makes its motion, and becomes to push the button of the micro-switch on the reverse side, the current is changed over and the motor is stopped. x. In the next place, when the switch is turned over to another place, the motor begins to rotate again, and the cam lever returns to the position shown in the figure from the lifted up position.. ･ And again, when we force-feed the liquid, the plunger is depressed, and in the same time, the ball valve recovers its function as a none return valve.. ". Now we come to the stage to make the refiection of the fluctuation of Pressure mentioned above on a syncro-oscilloscope. To this purpose we installed. two Strain Gauge Transducer Pressure Indicators (abbreviation: dynamic strain gauge), one of which is fit at the position 17 cm above the ball valve (we will call this for convinience "upper, high pressure position"==u.h.p.p.) and the other at the place 3cm under the ball'valve (we will call this "lower, low pressure position"==1.1. p.p.), and sent the current amplified by a broad zone. amplifier to the oscilloscope. - ･. These strain gauges were made by Shinko Electric Communication Co., and we used " MP 300" for the upper, high pressure position, and "MP 100" for the lower, low pressure position. -The characteristics of these are different.. The amplitude of "MP 300" is smaller than that of "MP 100!' under the same. condition, as shown in Fig. 2. ･.. ".

(3) Impact Vibration of Ball Valves 37 Counted from above facts, if one reading of pressure scale on the reflection of u. h. p. p. indicates 44 kg/cm2, then that of 1. I. p. p. indicates 18 kg/cm2. We. used also the amplifier DS 6/AX made also by Shinko Electric Communication Co., and used ･the same amplifier to the upper and lower strain gauges. The syncro-oscilloscope used is BP-2305 " Pulscope " made by Ando Electric. L). ' The bal! valves used are of three varieties shown below:--,. Dia. of ball. Inner dia. of Valve port. Dia. of push rod. a 1/4/X 3/8'/(9.525mm) 8.6mm 4.lmm￠ 4.1mm ip 5.6mm (6.35mm). b. c 3/16/'(4.7625mm) 4.3mm 3.0mm￠ For the purpose to alter the lifted height of ball valve, we made and prepared 8 cam disks of different diameters, and changed them at the moment of research. They are turned and adjusted to make the valve lift 2.2, 2.0, 1.8, 1.6, 1.4, 1.2, 1.0, O.8 mm.. But when we alter the size of ball valve, we must also exchange the valve. seat and push rod.. On the other hand we made the push rods of 7.75mm dia. and 8.04mm dia. other than above-mentioned one 4.1 mm dia. for the purpose "a" shown in the table above. These are used with the valve seat with 8.6mm inner diameter to get the passage of equal sectional area as that of "b" and "c". Besides this, we attempted the push rod of 6.73 mm diameter.. g3. Results Every photographic diagram subsequent to Fig. 2 represents the wave. f. form of the Iiquid impact vibration reflected on the screen of syncro-oscilloscope. i. The ordinate indicates the pressure and the abscissa means the sweeping time of electronic gun. Then the wave lenguh on the abscissa means the period of longitudinal vibration of the liquid. In this time we took the 2nd line from the bottom as the co-ordinate axis. (1) Effect of the valve Port diameter. The six diagrams shown in Fig. 3 show the wave forrn at the instant of opening of ball valves of the abovementioned 3 kinds port diameters under same condition that the pressure is 100 kg/cm2 and the ball lifted height 1.8 mm. The one reading on the abscissa indicates 1/1000 second, while that of the. ordinate of u.h.p.p. 44kg/cm2, and that of LLp.p. 18kg/cm2, according to the difference of characteristics between two strain gauges, but under same condition of oscilloscope. All six diagrams were taken under the same condition..

(4) '38 . ENoGucHi . ThetoptwodiagramsinFig.3areinthecaseof"a"(diameterofvalve port 8.6 mm, diameter of push, rod 4.1 mm), and that in left side is that meas.ured at the u.h.p.p. right side is that measured at the 1.I. p'p... The 2 diagrams in the middle are in the case of "b" (dia. of valve port 5.6 mm, dia. of push ron 4.1 mm), the left side is at the u. h. p. p. the right side. '. 'is at the l. 1. p. p.. The bottom 2 diagrams are in the case of "c" (dia. of valve port 4.3 mm. dia of push rod 3.0 mm). The left and right diagrams are in the same relationship as in the twocases above. We can observe from these diagrams that when the diameter of valve port becomes smaller, larger becomes the period of vibration at the u.h.p.p. and that which measured at the 1.1. p.p. are much inferior in pressure amplitude･. s. than that at the u. h. p. p.. In Fig. 4 the upper left diagram is the same thing shown in the middle left in Fig. 3, but the upper right diagram is the same thing but reduced in its scale of abscissa into 1/5, and the one reading indicates 5/1000 second.. The lower left diagram is the same thing shown in the bottom right in Fig. 3, but the right one is the same diagram but enlarged in its scale of' ordinate into 2.5/1, and the one reading indicates 7.2 kg/cm2. Everyone of these is in the condition that the ball lifted height is 1.8 mm,,. pressure 100 kg/cm2, but the valve port dia. 5.6 mm and 4.3 mm respectively. (2) Effect of lifted height of Ball valve.. ' Everyone in Fig. 5, Fig. 6, Fig.7 is the pressure-time diagram of impact vibration taken under every alteration of valve lifted height by O.2 mm, under constant pressure 100kg/cm2, and every one on left side is that taken at u. h. p. p. and in right side is that taken at 1. 1. p.p... ' The one reading of ordinate and abscissa in Fig. 5 is equal to that of upper diagrams of Fig. 3. The valve port inner diarneter remains the same and equals 8.6 mm.. ". Everyone in Fig. 6 is in the case that the valve port dia. remains 5.6 mm, but that of u. h. p. p. shown in left side, as shown in Fig. 4, is the reduced one. of that shown in the middle of Fig. 3 in abscissa scale into 1/5, and the one reading indicates 5/1000 second, as it is inconvinient that the one reading. repaains l/1000 second. ,. Everyone in Fig. 7 is in the case that the valve port diameter remains. 4.3 mm, but the diagrams on the left side, under same reason as in Fig. 6, are ,those reduced in abscissa scale into 1/5, and those on the right- side are the ,enlarged ones of that shown in the bottom right in Fig. 3 in ordinate scale into 2.5/1, and the one reading indicates 7.2 kg/cm2, as they are too smal! in pressure amplitude. After observation of these 3 figures, we find out that at the u. h. p. p. the. a.

(5) Impact Vibration of Ball Valves 39 pressure amplitude does not almost change, in spite of the alteration of valve.lifted height, and also the alteration of the valve port diameter; and that at the 1.1. p.p. the pressure amplitude does not almost change by the alteration of valve lifted height, but becomes suddenly small when the valve port'reducesH }. its diameter; and also that the pressure amplitude at the 1. 1. p. p. is far small--. er in comparison with that at the u.h.p.p. and this tendency becomes very'. remarkableasthereductionofvalveportdiameteretc. -p. But the sweeping on the screen becomes unstable as with the reduction 'of' valve port diameter, and it will be hard to obtain an exact representation.. (3)Effectofthealterati'onofPressure ･･ The records which are determined under pressure alteration in five stages･ of 100, 80, 60, 40, 20kg/cm2 are shown in Fig. 8, Fig. 9, Fig. 10, when the pressure is accumulated in the cavity beyond the ball valve which then acts.. asanone-returnvalve. ' '-. In these three figures, the diagrams on the left side show the results at. the u. h. p.p., while on the right side show that at the 1. 1. p. p. ･ Fig. 8 shows for example the case when the valve port diameter is 8.6 mm,.. and the lifted height of ball is 1.8mm. In every diagram the lateral and. longitudinalscalesareequalasinFig.5. ･ . Fig. 9 shows for example the case when the valve port diameter is 5.6 mm, and the lifted height of ball is 1.8 mm. The lateral and longitudinal scales are equal as in the left hand diagrams of Fig. 6, but the diagrams on right side･ are equa! in lateral scale as in the right hand diagrams of Fig. 6, but multi--. plied2.5timesinlongitudinal'scale. ' ' Fig. 10 shows for example the case when the valve port diameter is 4.3 mm. and the lifted height of ball is 1.8 mm. In every diagram the lateral apd longitudinal scales are equal as in the right and left hand ones in Fig. 7, but longi-. '. tudina! scale of right hand ones is 2.5 times of left hand ones. Obeerved from these three figures, we found that the pressure amplitude of vibration is aw-. fully affected by the initially accumulated pressure. .. (4) Effect of diameters of Push rods ,. When we use the push rod 4.1mm dia. with the valve port 5.6mm dia., the cross sectional area becomes 11.43mm2, and when we use the push rod 3.0 mm dia. with the valve port 4.3 mm dia., the cross sectional area becomes･. 7.45mm2. But as when we use the push rod 4.1mm dia. with the valve port 8.6 mm dia., we get a cross sectional area 44.89 mm2, former will be about 1/4. an g J<i/h6efifwtehetriyaFreerlnaining the va'ive port diameter the same as 8･6 mm, to get the equal sectional area as two formers, by altering the diameter of push. rod, we have two rod diameters 7.75mm and 8.04mm. Added a push rod 6.73 mm dia. ,to get the cross sectional area 22.45 mm2, that is the half of the.

(6) :40 ･ F.NoGucHI ･former,weperformedthe'experiment.- The experiments were carried out under the constant condition that pres's"re ixep/,'i."Siii20h,k{/,CpMEg.V,a,iV,eh,iQtgeSheetg.h,,t ,ii8,Mbge", ni,ntioned i/2 sectionai .. ･area, the middle two the cass of 1/4, bottom two the 'base of 1/6, and the left. iones are in the case of combination of valve port 8.6 mm dia. with thick push rods, while the right opposite ones are in the cases that the valve ports 5.6 mm ･dia. and 4.3 mm dia. respectively, in comparison with the former.. -J. ,Theseareallmeasuredattheu.h.p.p.. In regard to the scale, the top one is equal to the upper left one in Fig. 3 .?antdertahi,escOiiheeritaorei/esq.Uai tO the top right one in Fig. 4, with the reduction in. ･ Fromtheabove,weunderstandthatthe'waveformsatu.h.p.p.present similarity each other, when the cross sectional area of valve ports becomes ･equal.. Fig. 12 shows the results measured under equal condition with Fig. 11 at 'the 1.1.p.p., using the same valve port and push rod･, and also in the same. ･arrangement with Fig. 11. ,' -. The lateral scale is that the one reading shows 1/1000 second, and the lon-. gitudinalscaleis2.5timesofthatinFig.3. ' We see from these rescults that the cases of thin valve ports resemb!es ･somewhat to the cases of thick push rods, but sorry to say they are not quite. -resembled. ･ These facts may be perhaps by the reason that we shortened the length ･of valve port for the fear that the push rod may be too thin to buckle, and .tbheactothhees 2Chriene.n PrOjeCtiOn Will be very unstable when the valve port diameter. '. '. '. 'g4. Conclusion - ' '. ,ciusiAtAtse:r SUMMarised the e;perimentai resuits above, we haye got next con-. (1) The pressure amplitude almost remainsthesame in spite of the vari･ous alterations of the valve lifted height. Author dare to reason that the vibration must take place at a very short instant when the ball valve 'is pushed 'up and there opened a verysmall gap to let in a sudden rush of high pressure .liquid around it, and its time required is too short to be compared with that. ･of the valve lifting. ' ' (2) The pressure amplitude of vibration is awfully affected by the pressure 'initially accumulated in the high pressure cavity.. This is perhaps, by the assumption in former (1), to be reasoned that by 'the rush of high pressure liquid into the valve port, the energy of rushing 'velocity is in proportion with the pressure difference. (3) The pressure amplitude of vibration at the 1. 1. p. p. is far smaller than. i.

(7) Impact Vibration of Ball Valves 41 '. that of u.h.p.p., when we open the valve under a certain accumulated pressure, and moreover the smaller the valve port, larger becomes this difference. From the fact that the sectionnal area of the passage from the ball valve .. ts. to the 1.1. p.p. is narrower than that to the u,h.p.p., and also from the fact that smaller the valve port dia., larger becomes this difference, we guess that the vibration which takes place at the instant at the scarce opening of ball. valve Suffer a more resistance owing to the small sectinal area when it is transmitted downward than is transmitted upward, and loses more. energy of ¥A2r9otsisO.n, and also that the narrower the valve port passage, bigger will be. (4) About the fact that with the narrower port, bigger becomes the period, i,"1,3W,a,ige{,b,eC,O.pe,e,S,tg,e .fi.e,q,.",e,",C.Y.2t,t,h.e, ",i.h6p･p･･ we guess the reason that. `. K.

(8) 42. F. NoGucHi. f , Dynamicstra:ngouge･. 'pregStire 'qa' b'ij'e. C75 ./ , 1- .-1 .,- -. s .). Syncro-oscilloscope. ". Valve body. Ball valve ([IIIIg). Broad. Dynamic. zone. amplifier. Push rod. PumP. straln gauge. i' "j. Jae. s<[3i)>. 0. [ Pi,ston cup. Electric moter. l. Piunger. Cam lever. Cam disk. @oO. Micro switch. Batteries. DC. Change-over. l2 V. switch. r 1. ･ L. --S 1. Fig. 1. :. ×. -. Schematic diagram of the experimental arrangement.. si. 4. Fig. 2. Calibration..

(9) Impact Vibration of Ball Valves upper,. 43. high pressure position lower, low. pressure posltlon. Va lve. port dia.. 88 44' e. 36 i8. 8.6 m m. o. o'. l254 56789 10. o ". Ol. 2345 6789. IO. 5,6mm. 4.3mm Fig.3 Effect of. the valve port diamecer.. (p==100 kg/cm2 valve lifted height 1.8 mm, 1 ms-5v). 1. 88 44. 0. to reduce abscissc,. 88. into i/s. 44 o. '-"-""""･ee)･. 8 9 IO O5 10 O12345 .6 7 (Valve port dla, 5,6mm e,h.p.p. ). i5. 20 25 30 35-40 45 50. lms 5v. to multiply. 36. ordinate. i8. by 25 -----)･. o. ol 5v 254 l'ms. 5. 6789IO os234. (Vaiveportdia4.3mmLLp,p,). Fig. 4 Alteration of the reading scale. (p= 100 kg/cm2 valve lifted height 1.8 mm). 5ms 5v. I4,4 ･Z 2. [o. 56 78 1rns 9 IO 2v.

(10) 44. F. 'NoGucHi tl,pp.. u,hp.p. valve Iifted. height. 2,2mm. .. 56. 88 44. ". l8. 2D mm. o. o. O[23'4 5617 89 IO. [O. 1,8 mm. i,6 m m-. l4 mm. st. I2 mm. -. i,Omm. O.8mm. (P=IOOkg/crr?) lms5v. ims 5v. Fig. 5. Effect of the valve lifted height at the valve 8.6 mm. dia..

(11) 45. Impact Vibration of Ball Valves. u,h p p.. L1.p,p.. valve Iifted. height. 2.0mm e. e.. 36. 88,. l.8mm. l8 ,. 44･. o. o. O123 ･4 56789 10. O 5 10 i5 20 25 30 35 40 45 50. i.6mm. 1,4mm. l.2mm. b. l.Omm. O,8mm''. 5ms 5v. (P=lOOkg!cm2) Fig. 6. Effect of' the valve lifted height at the valve 5.6 mm. dia.. '. {ms 5v.

(12) 46. E NoGucHI u h.p p.. Li.p.p.. valve 1ifted. height. 20 mm ,. ". 88'. 14.4. l.8mm. 44. Z2 '. o. o. O 5. IO･l5,'20･25 30I35 .40L45i50. O l 2 3J 4 5･ 6- 7･ 8･ 9･ IO. l,6mm. 1,4 in m i. 'p. l2 mm. v'. ". hO mm. Q8mm 5msi 5v･. (P=lOOkg/cm2) Fig. 7. Effect-of the valve lifted'height at the valve 4.3 mm. dia.. lms 2v.

(13) Impact Vibration of Ball Valves. uhpp.,, e. 47. l.LP.P, ･ pressure -1･. i l.. '. J lv. i,OOk'gltm2. tr. t. /.t. t/. 11･. .11. ./. :. 80 ". 60 ". .. ･..L -- i."･k'r[/''V. ･. ,...,,,,--･,i':'･･--･'. I.i ,, l,･. ,. v''. .1,l"/,il"'`i"'1,'i'･,l'1'ILI'. : /. i. i 40"-. l I. l. '. 1'. m' s15v. '. : '. 20" i 1. K. ..- t,.,---.-,,... --....'. lms 5v. tt tt change Fig. 8 Effect･'･Of･the･ pressure. (Valve Iifted height L8mm) valve 8.6mm dia.. ' at･the.

(14) E NoGucHi. 48･ /. u,hp.p,. 1.I.p,p. .. pressure. IO O kg lc m2 -s. 88. l4.4. 80 n. 44. Z2. o. o o. Ol254 56789 10. 5 IO l5 20 25 30 35 40 45 50. 6o i･. 40". i. 20 ":. g. 5ms･ 5v. (Volve IMed height l.8mm) Fig,9 Effect of the pressure change at the valve 5.6 mm dia.. lms 2v.

(15) Impact Vibration of Ball Valves. 49). .;.. ,-. 'i' '. )'' 'i !,,, ,-. /t. ' i ' '. t ttt. t.f,, l:l,p,:p.. u. h. p･p･. '. ). pressure IOOkg/c.2 /. 80". 60". 40-. ･'. lms"2v. :(. l.. 20". ''. ,l. ;Jii'. .}:. k,･, ,. n:.. 5ms 5v. (Valve lifted height l.8mm) Fig. 10 tt/ tt tt. t. t tt../.. Effect of the P;essure Cha". '. ttttt. iilil.i-l',i,11111.,illilliillll,il.illiliSliliiiill.kl.,..V.i･iiili,/Y,i･iiii.iiii.11,li,il･･li･:･itilii'ii･i/"iiiiL?. dia. /1･･･,gs.,, ,IIrliii. "'i'･i ''''. -t h. L... ･･g tt･･/.

(16) $o. E. NoGucHI. "volve port gdlo.. 8.6 m m .push rod. Sectional. 88. ore o.. 44. rdiO.. o. 22.45mrn2. 6.73mm. 23456789 10. o}. .. valve port. xvalve port "dia.. i8.6mm ;pvsh rod klia,. 88. 88. 44. 44. o. Il,43mm2. ･7. 73 mm. o. dia.. 5,6mm. o. dia. ' 4.I m rn. O 5 10 I5 20 25 30 35 40 45 50. 5 IO' 15 20 25 30 35 40 45 50. 'valve port. dia,. `86mm pvsh rod .dia,. -). push rod. valve port. 88. 88･. 44. 44. o. i804mm. Z45mm2. dia,. 4.3 mm . push rod. o. dia,. O5IO l5 20 25･30 35 40 Ob 101520253035404550 t. with- thick push rod. 3,Omm 45. 5o. Eig･.,ytr,,gsm,s,are･zo,e,gf.?hg,:a,lvgg,?l･g.m.m,･:.Sgzl. s,. (atu.h.p.p.) .･, /. .,(p=100kglcm2va`lveliftedheight 1.8 mm). .,,,,..,,･"'. i. tt. ,...',/'.･.･･=':,L,'.--r･･".';;ll''' ....''.', ･i. ' ' t/,..- , ..--,., ,1... '. '. "valve port qdia.. ･8,6 m m epush rod fdia.. l4g. .jtA -, '' sectiondl''' area. -'. Z2. o. 22.45mm2. g6.73 mm.. o.. /-. '2 ･'3 4 56 789 10. twalve pert vdia,. ':8.6 mm co'osh rod futia.. 14.4 dia.. 1･44. 72. Z2. o. lI.43mm2. o l4t4. Z2. tpush rod ftdia,. 's･. 6'-. Ol. ･7 8 9' 10. . .･.. '. 'walve port. :-8,6mm. i23. 14 '1s-;. 5.6 m m '. push rod O dia.. . ,-t .--S V.. 7, 73 itri m. eaia.. ". valve port. 23456. 4,1mm. 789 IO. valve port. -. l4,4 dia.. 43 mm. Z2 push rod. o. O dia,. 8,04mm. 7,45mm2. Ol 25 45. 678910 Ol2. 3.4 5 6. Comparison of the valves 8.6 mm dia. with thick push with the valves of equal sectional area. (at 1. 1. p.p.). Fig. 12. (p =100 kg/cm2 valve lifted height 1.8 mm). '. 78 ro d,. 9 IO. 3.0mm. t.

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