GB2192737A

GB2192737A - Self regulated pressure control valve

Info

Publication number: GB2192737A
Application number: GB08716496A
Authority: GB
Inventors: Yoshihiko Hasegawa
Original assignee: TLV Co Ltd
Current assignee: TLV Co Ltd
Priority date: 1986-07-15
Filing date: 1987-07-14
Publication date: 1988-01-20
Anticipated expiration: 2007-07-14
Also published as: SE8702833L; DK353987D0; IT8721269A0; DE3723284A1; FR2601748A1; DK353987A; JPS6320603A; GB2192737B; GB8716496D0; CA1281609C; PT85326A; NL192353B; CN1009315B; SE8702833D0; IT1222025B; AU586570B2; AU7526587A; NL8701652A; NL192353C; KR920008002B1

Description

1 GB2192737A 1 SPECIFICATION The control unit controls the driving unit on

the basis of the functional relation between Self-regulated pressure control valve the position of the pressure regulating unit and the secondary pressure corresponding to The present invention relates to a self-regu- 70 the controlled pressure to adjust the secon lated pressure control valve capable of con- dary pressure to a desired value, namely, the trolling the secondary pressure, namely, the set pressure value.

pressure of an associated controlled system, In one embodiment of the present invention, at a predetermined set level through the self- the control unit comprises a computer includ- regulation of the pressure setting condition 75 ing arithmetic means, correcting means and thereof on the basis of a control signal corre- memory means.

sponding to the current pressure of the con- According to the present invention, when a trolled system detected by pressure detecting randomly selected pressure is set by means means. of the pressure setting unit, the operating The applicant of the present invention pro- 80 means of the control unit calculates an appro posed an automatic pressure reducing diapriate position of the pressure regulating phragm valve in Japanese Patent Application member of the pressure regulating unit on the No. 59-207779. This automatic pressure re- basis of the functional relation between the ducing diaphragm valve comprises a pressure secondary pressure and the position of the reducing diaphragm valve unit, a pressure set- 85 pressure regulating member, whereafter the ting unit including a pressure setting spring, an control unit provides a control signal to the actuator for operating the pressure setting driving unit to adjust the position of the pres unit, and a control unit which provides a con- sure regulating member to a calculated appro trol signal to actuate the actuator when the priate position so that the secondary pressure pressure deviation of a detected secondary 90 is regulated to the set pressure.

pressure namely' the controlled pressure, When the secondary pressure has been thus from a trget pressure exceeds a predeter- adjusted to the set pressure, the self-regulated mined reference deviation so that the pressure valve unit starts mechanical pressure control deviation is reduced to zero. operation in the conventional manner. When ' This automatic pressure reducing diaphragm 95 further fine control of the secondary pressure valve is capable of stable pressure reducing is necessary, it is desirable to provide a sec operation to stabilize the secondary pressure ondary pressure detecting means to detect the through mechanical action while the pressure secondary pressure continuously or periodi-' deviation of the secondary pressure is below cally and to control the driving unit by a cor the reference pressure deviation. However, 100 rection signal calculated by the operating since the automatic pressure reducing dia- means of the control unit on the basis of the phragm valve regulates the secondary pres- difference between the set pressure and the sure on the basis of the result of comparison detected secondary pressure to control the between the detected pressure deviation and second pressure continuously or periodically.

the reference pressure deviation, it takes a 105 In this way the selfregulated pressure con long time-to stabilize the secondary pressure trol valve is capable of rapid response to vari at the predetermined set pressure. ations of the secondary pressure and of in Accordingly, it is an object of the present stantly regulating the secondary pressure, invention to provide a self-regulated pressure namely, the controlled pressure, to a set pres- control valve capable of rapidly adjusting the 110 sure, namely, a target pressure.

secondary pressure to a predetermined set The above and other objects, features and value. advantages of the present invention will be The present invention utilizes the functional come more apparent from the following de relation between the position of pressure re- scription of some preferred embodiments gulating means and the secondary pressure of 115 thereof taken in conjunction with the accom a self-regulated pressure reducing valve includ- panying drawings, in which:

ing the pressure regulating means and driving Figure 1 is a fragmentary sectional view of means for driving the pressure regulating a self-regulated pressure control valve, particu means. larly showing the pressure regulating unit To achieve the object of the invention, the 120 thereof; present invention provides a self-regulated Figure 2 is a graph showing the relation be pressure control valve comp rising: a pressure tween the,pressure regulating member of a control valve unit, a detecting unit for detect- pressure regulating unit and the controlled ing the secondary pressure, a pressure regu- pressure; lating unit for regulating the secondary pres- 125 Figure 3 is a block diagram of a self-regu sure of the pressure control valve unit, a driv- lated pressure control valve, in a first embodi ing unit for operating the pressure regulating ment, according to the present invention; unit, a control unit for controlling the driving Figure 4 is a block diagram of a self-regu unit, and a pressure setting unit for setting a lated pressure control valve, in a second em- set pressure. 130 bodiment, according to the present invetion; 2 GB2192737A 2 and compression of the pressure setting spring 2 Figure 5 is a block diagram of a self-regu- and hence to the set pressure as shown in lated pressure control valve, in a third embodi- Fig. 2. The present invention effectively uti ment, according to the present invention. lizes.such a relation between the distance of Figs. 1 and 2 show a first embodiment of 70 shift of the lower end of the pressure regulat the application of the present invention to a ing screw rod 8 and the set pressure.

- pressure reducing valve 1. Referring to Fig. 1, - Referring to Fig. 3, showing a first embodi the pressure reducing valve 1 has a pressure merit of the present invention, the self-regu setting spring 2 having one end seated on a iated pressure control valve comprises a pres t spring seat 3 and the other end seated on a 75 sure reducing valve 1, a pressure regulating 1 spring seat 6. The spring seats 3 and 6 are unit 50 including the pressure regulating screw pressed against a diaphragm 4 and against rod 8, a driving unit 52 including the motor the lower end, as viewed in Fig. l., of a pres- 15, a pressure detecting unit 54, a signal con sure regulating screw rod 8 through a ball 7, version unit 55, a control unit 56 including a respectively. The secondary pressure of the 80 computer storing screw rod position data pressure reducing valve 1 prevails in a pres- representing the functional relation between sure chamber 5 covered with the diaphragm the screw rod position and the controlled 4. The position of the diaphragm 4 is depen- pressure, and a pressure setting unit 58. In dent on the pressure balance between the the ' first embodiment, the motor 15 is a step pressure applied thereto by the pressure set- 85 ping, motor.

ting spring 2 and the secondary pressure pre- The pressure sensor of the pressure detect vailing within the pressure chamber 5. Since - ing unit 54 detects the secondary pressure of the secondary pressure control function of the the pressure reducing valve 1 and gives a diaphragm 4 is well known, a description pressure signal representing the secondary thereof will be omitted. 90 pressure to the signal conversion unit 55.

Anexternal thread 9 is formed in the lower Then, the signal conversion unit 55 converts portion of the pressure regulating screw rod the pressure signal into a corresponding digital 8. The threaded lower end of the pressure pressure signal, and supplies the same to the regulating rod 8 is screwed in a fixed member computer of the control unit 56.

provided with an internal thread 10 in the cen- 95 Upon the reception of a set pressure signal tral portion thereof. An axial' bore is formed in representing a set pressure from the pressure t e upper portion, as viewed in Fig. 1, of the setting unit 58, the computer calculates a pressure regulating screw rod 8. A retainer 11 screw rod position corresponding to the set retaining balls 12 is inserted in the, axial bore pressure for the pressure regulating screw rod of the pressure regulating screw rod 8. A 100 8 on the basis of the screw rod position data spline shaft 13 is fitted in the axial bore of previously stored therein, and then supplies a the pressure regulating screw rod 8 so as to pulse signal corresponding to the calculated - engage with the balls 12. The spline shaft 13 screw rod position to the driving unit 52 to is connected through a reduction gear 14 to drive the pressure regulating unit 50 so that the output shaft of a motor 15. -105. the pressure regulating screw rod 8 is moved Since the pressure regulating- screw rod is. to.the calculated screw rod position; conse engaged with the internal thread 10 of the quently, the secondary pressure of the pres fixed member, the pressure regulating. screw sure reducing valve 1 is adjusted instantly to rod 8 is rotated through the spline shaft 13 the set pressure. The angle of rotation of the so as to shift downward,when the output 110 output shaft of the stepping motor 15 is pro shaft of the motor 15 rotates in one direction, portional to the number of pulses of the pulse and thereby the pressure setting spring 2 is signal, and hence the position of the pressure compressed through the spring seat 6 by the regulating screw rod 8 corresponds to the pressure regulating screw rod 8 to increase number of pulses of the pulse signal.

the set pressure. On the other hand, when the- 115- The pressure detecting unit 54 detects the output shaft of the motor 15 rotates in the secondary pressure continuously or periodi - opposite direction, the pressure regulating cally and the signal conversion unit 55 feeds screw rod 8 is rotated in the-opposite direc- digital signals to the control unit 56 in like tion so as to shift upward, and thereby the manner. The computer of the. control unit 56 compression of the pressure setting spring 2 120 compares the detected secondary pressure is reduced to reduce the set pressure. with the set pressure. When the deviation of The distance through which the lower end the detected secondary pressure from the set of the pressu re regulating screw rod 8 is pressure is within a predetermined range of moved from a predetermined reference posideviation, the control unit does not provide tion (a position where the lower end of the 125 any signal to actuate the driving unit 52.

pressure regulating screw rod 8 is in contact When the deviation of the detected secondary with the spring seat 6 through the ball 7 withpressure from the set pressure is greater than out compressing the pressure regulating _spring the limit value of the predetermined range of 8), which will be referred to as---screwrod. deviation, the computer calculates a correction position", is proportional to the amount of 130 distance through which the pressure regulating 3 GB2192737A 3 screw rod.8 needs to be shifted to correct stored in the memory means is then replaced the deviation, and that on the basis of the with S5 + AS.

difference between the detected secondary When the same set pressure is given to the - pressure and the set pressure and the screw control unit to adjust the controlled pressure rod position data stored therein, and then pro- 70 to the same target pressure after the pressure vides a control signal representing the calcu- regulating screw rod 8 has been shifted from lated correctiom distance for secondary pres- the previous screw position to change the set sure correction to actuate the driving unit for pressure, the computer calculates the correct shifting the pressure regulating screw rod 8 screw position to adjust the. secondary pres- for the fine adjustment of the secondary pres- 75 sure instantly-to the target pressure.

sure. When the pressure control system of the For example, when the set pressure is 5 self-regulated pressure control valve is thus kg/cM2, the reference range of deviation is constituted, the pressure control system gen 0. 1 kg/cM2, and the detected secondary pres- erates an ideal control data even when the - ure is 4.5 kg/CM2, the computer calculates a 80 operating condition of the pressure reducing correction distance corresponding to the pres- valve is varied, so that the self-regulated pres sure deviation of 0.5 kg/Crn2 on the basis of sure control valve is able to operate at a high the screw rod position data to shift the presresponse speed.

sure regulating screw rod 8 accordingly. Basically, the second embodiment illustrated For a more advanced pressure control, digi- 85 in Fig. 1 and 4 is similar to the first embodi tal data representing the functional relation be- ment in constitution and function. The second tween the set pressure and the screw rod embodiment employs a rotary potentiometer position, for example, a predetermined correla- for detecting the position of the pressure re tion between the set pressure and the screw gulating screw rod 8, and a reversible motor rod position represented by set pressures of 90 instead of the stepping motor, for driving the 1 kg/CM2 intervals and the corresponding pressure regulating screw rod 8.

screw rod pbsitions, is stored in the table of Referring to Fig. 4, the second embodiment the memory means of the computer, and the comprises a pressure reducing valve 1, a control operation and the correcting operation pressure regulating unit 50, a driving unit 52, are executed on the basis of the digital data 95 a pressure detector 54, a signal converter 55, according to the predetermined- correlation. a control unit 56, a pressure setting unit-58, a When a correction is made, the digital data reduction gear 14, and a rotary potentiometer representing the previous screw rod position 20.

is replaced with the corrected data represent- Referring to Fig. 1, the rotary potentiometer ing the new screw rod position to update the 100 20 is operatively interlocked with one of the table of the memory means. gears, not shown, of the reduction gear 14.

For example, suppose that screw rod posi- The output voltage of the potentiometer 20 is tions 84 and 85 stored in the memory means proportional to the distance of shift of the of the -computer correspond to. set pressures, pressure regulating screw rod 8 from the ref- more specificallyl set secondary pressures, of 105 erence position (a position where the pressure 4 and 5 kg/CM2, respectively. When the valve regulating screw rod is in engagement with is set for the set pressure 5 kg/cm2 by means the pressure setting spring 2 without com of the pressure. setting means, the motor pressing the latter), namely, the screw rod. po drives the pressure regulating screw rod to sition. Accordingly, the output voltage of the the corresponding screw rod position 85. 110 rotary potentiometer 20 represents the screw When the reference deviation range is 0.1 roO position and hence the secondary pres kg /CM2, the motor remains stopped so long sure, i.e., the controlled pressure. In the sec as the deviation of the actual secondary pres- ond embodiment, screw rod position data, sure from the set pressure is within the referrepresenting the functional relation between ence deviation range. 115 the screw rod position represented by the Suppose that the set pressure is 5 kg/CM2, output voltage of the rotary potentiometer 20 the reference deviation range is 0.1 and the secondary pressure is stored in the kg/CM2, and the prevailing secondary pressure computer.

is 4.5 kg/CM2. The computer will then calcu- The rotary potentiometer 20 may be re late a screw rod position correcting displace- 120 placed by a linear potentiometer or a differen ment AS corresponding to the deviatiom. 5.0 tial transformer. When a linear potentiometer -4.5 = 0.5 kg/CM2 by using the equation: is employed, the arm of the linear potentiom eter is arranged so as to move linearly to - AS = (S5 S4) x 0.5/(5 - 4) gether with the pressure regulating screw rod 125 8. When a differential transformer is em The motor then drives the pressure regulating ployed, the core of the differential transformer screw rod for the calculated screw rod posi- is arranged so as to move linearly together tion correcting displacement AS to increase with the pressure regulating screw rod 8.

the secondary pressure from 4.5 kg/CM2 to The control unit 56 continuously supplies a 5.0 kg/CM2. The initial screw rod position 85 130signal to the driving unit 52 until the output 4 GB2192737A 4 signal of the rotary potentiometer 20, namely, regulating element of said pressure regulating the screw rod position signal, coincides with a means is shifted to a position to adjust the signal given to the control unit 56 by means controlled pressure to the set pressure.

of the pressure setting unit 58. Since the rest 2 ' A self-regulated pressure control valve as of the functions are the same as those of the 70 claimed in claim 1, characterized in that said first embodiment, a description thereof will be control means includes a computer which omitted to avoid duplication. stores control data representing said predeter - The third embodiment shown in Fig. 5 com- mined functional relation between the position prises a pressure reducing valve 1, a reduction of the pressure regulating element of said gear 14, a rotary potentiometer 20, a pres- 75 pressure regulating means and the controlled sure regulating Unit 50, a driving u'nit 52, a pressure, which computer calculates a position control unit 70, and a pressure setting unit, 72 where said pressure regulating -element is to -including a potentiometer. be positioned on the basis of said control The control unit 72 does not include a com- data and-a set pressure signal provided by puter. The third embodiment is capable of 80 sa id pressure setting means (58) the position most simply controlling the secondary-pres of said pressure regulating element being de sure on the basis of the relation between the tected by a position detecting means such as - screw rod position and the secondary pres- a potentiometer and said control means con sure, i.e., the controlled pressure. The rotary - trolling the operation of said driving means so potentiometer 20, which is -operatively con- 85 as.to drive said pressure regulating means un nected to the reduction gear 14, gives a voltil the detection signal of said position detect taga signal representing -a screw rod position ing means coincides with a signal representing corresponding to the secondary pressure to the position of said control means calculated the control unit 70, while the potentiometer of by the computer on the basis of the control -the pressure setting unit-72-gives a voltage 90 data and the signal representing the set pres signal representing a setpressure to the con- sure. - trol: unit 72. The control unit 72 compares the 3. A self-regulated pressure control valve as voltage signal representing the screw rod po- claimed in claim 1, characterized in that said sition and -the -voltage signal- representing the control means includes a computer which set pressure, and then gives a control signal 95 stores control data representing the predeter - to the driving unit 52 to shift the pressure mined functional relation between the position regulating -screw- rod until the voltage signal of the pressure regulating element of said - provided by the rotary potentiometer 20 coin- pressure regulating means and the controlled cides with the voltage signal representing the pressure, said driving means including a step set pressure. 100 ping motor said computer calculating, on the The rotarV potentiometer 20 may be re- basis of a set pressure signal given thereto placed by a linear potentiorrieter or a differen- from said pressure setting means a pulse sig tial transformer as mentioned in the descripnal whose number of pulses corresponds to a tion of the -second embodiment. positiorl where said pressure regulating ele- Although the invention has been described 105 ment is to be positioned, and then supplies with referend ' e to the preferred embodiments the pulse signal to the stepping motor to re thereof with- a- certain degree of particularity, -ii gulate the controlled pressure to the set pres will be-understood that many changes and sure.

variations-will readily occur to those skilled in 4. A self-regulated pressure control valve as thec art without -departing from -the scope of 110 claimed in claim 2 or 3, characterized by a the -invention. controlled pressure detecting means for de tecting the controlled pressure, wherein the

Claims

CLAIMS detection signal provided by said controlled

1. A self-regulated pressure control valve pressure detecting means and the set pres- characterized, by 115 sure signal provided by said pressure setting a pressure control valve, means are compared continuously or periodi a pressure setting means for setting a set cally by said. control means to determine the pressure; deviation of the controlled pressure from the a pressure regulating means for regulating set pressure, if there is any significant devia the -controlled pressure of said pressure contion of the controlled pressure from the set trol valve; pressure, the computer calculates a correction a driving means-for driving said pressure distance through which the pressure regulating regulating means; and element of said pressure regulating means a control means for- controlling the operation needs to be shifted from the position it occu of said driving means on the basis of a set 125 pies on the basis of the deviation and the pressure set by said pressure setting means control data stored in the computer to correct and the predetermined functional relation be- the controlled pressure so that the controlled tweeh the position of the pressure regulating pressure coincides with the set pressure.

element of said. pressure regulating means and 5. A self-regulated pressure control valve as the controlled pressure so that the pressure 130 claimed in claim 4, characterized in that the GB2192737A 5 position of the pressure regulating element of said pressure regulating means determined by said control unit on the basis of the, difference between the controlled pressure signal repre- senting the detected controlled pressure and the set pressure signal representing the set pressure is stored in the computer, as a new correct position of the pressure regulating element of said pressure regulating means.

6. A self-regulated pressure control valve as claimed in claim 1, characterized in that the control means controls ' said driving means to operate until the detection signal corresponding to the position of the pressure regulating element of said pressure regulating means, detected by the potentiometer or the like of said position detecting means coincides with the set pressure signal representing a set pressure provided by a potentiometer or the like of said pressure setting means.

7 ' A self regulated pressure control valve as described -hereinbefore with respect to Figures and 3, Figures 1 and 4, or Figures 1 and 5 of the accompanying drawings.

Published 1988 at The Patent Office, State House, 66/71 HighHolborn, London WC 1 R 4TP. Further copies may be obtained from The Patent Office, Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Burgess & Son (Abingdon) Ltd. Con, 1/87.

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