US3528440A - Vapor-liquid ratio monitor - Google Patents

Description

6 Sheets-Sheet l Filed Oct. 20, 1969 Sample FIG.1

Reference Signal INVENTOR.

Affomey Sept. 15, 1970 J. PLucKER In VAPOR-LIQUID RATIO MONITOR 6 Sheets-Sheet 2 Filed Oct. 20, 1969 FIG? 3o RATIO m m BME Sept. 15, 1970 J. PLUCKER nl 3,528,440

VAPOR-LIQUID RATIO MONITOR Filed Oct. 20, 1969 6 Sheets-Sheet 5 INVENTOR. BY JU//Z/s P/UC/ff, DI

A//omey f .@ZO V20/o4 Sept- 15, 1970 J. PLUCKER 1u 3,528,440

VAPOR-LIQUID RATIO MONITOR Filed oct. 2o, 1969 e sheets-sheet 5 Q Q m.

INVENTOR. Ju//L/s P/uc/feglZ BY il. www f//wwz ATTORNEY Sept- 15, 1970 J. PLucKER lll 3,528,440

VAPOR-LIQUID RATIO MONITOR Filed oct. 2o, 1969 e sheets-sheet s Unted States Patent O 3,528,440 VAPOR-LIQUID RATIO MONITOR Julius Plucker III, Pitman, NJ., assignor to Mobil Oil Corporation, a corporation of New York Continuation-impart of application Ser. No. 861,211, July 23, 1969, which is a continuation of application Ser. No. 562,621, July 5, 1966. This application Oct. 20, 1969, Ser. No. 867,544

Int. Cl. G01n 7/14 U.S. Cl. 137-3 11 Claims ABSTRACT OF THE DISCLOSURE A vapor-liquid ratio monitor is disclosed which comprises valve means for feeding a predetermined volume of a motor fuel to a chamber. Vertically movable means within the chamber is adapted to move in response to the vapor pressure of the fuel until a predetermined pressure is present above the sample within the chamber. The amount of the vertical movement of the movableV means provides an indication of the vapor-liquid ratio of the sample.

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of copending application Ser. No. 861,211, led July 23, 1969, which is a continuation of application Ser. No. 562,621, filed July 5, 1966, and now abandoned.

BACKGROUND OF THE INVENTION Field of the invention This invention is directed to a method and apparatus for determining the vapor-liquid ratio characteristics of petroleum products. More particularly, this invention is directed to the automatic determination of the vaporliquid ratio of gasoline.

Description ofthe prior art The vapor-liquid ratio of gasoline is a measure of the amount of light ends present in a given fuel. This has been further defined by the ASTM as follows: Vaporliquid ratio of a gasoline, at any specified temperature and pressure is the ratio, at that temperature and pressure of the volume of vapor in equilibrium with liquid to the volume of sample charged, as a liquid, at 32 F.

The volatility characteristic of motor gasoline is recognized as an important property, from the standpoint of proper engine operation. Too large a proportion of light ends can result in a vapor-lock and other hot weather problems in engine fuel systems. Too little an amount of the light ends can adversely affect the engine starting and warm-up characteristics of the gasoline. A further important factor results from the favorable economics of blending in light products where feasible. For example, butane, a relatively low cost component, is economically upgraded by use in gasoline which is sold for a higher price. Butane has a high octane number; however, its use in gasoline is limited because of its high volatility. Therefore, a device which accurately and continuously monitors the vapor-liquid ratio of a gasoline would be of great value in producing a product of good quality at the lowest price. Such a device would also be of value as a control element for blending in the maximum amount of light products within an acceptable limit for the vapor-liquid ratio.

Even though a great need has existed for the determination of the vapor-liquid ratio of gasoline, one of the most prevalent tests for this characteristic is still its indirect measurement by the Reid Vapor Pressure method, normally in conjunction with one or more ASTM disice tillation point measurements. In some cases, however, it was recognized that these tests did not provide suflicient information or that the empirical correlation of the measured parameters with the actual vapor-liquid ratio was not satisfactory.

Considerable work has been done on new methods to measure the actual vapor-liquid ratio of gasoline. Data obtained by these procedures are considered to be more closely related to engine performance aspects of volatility than that obtained by the Reid Vapor Pressure and ASTM distillation. The principal drawbacks to most of these methods are the complexity of the apparatus or the procedure and the length of time necessary to obtain results. These drawbacks are particularly acute in any attempt to determine the vapor-liquid ratio continuously.

SUMMARY OF THE INVENTION In accordance with the present invention there is provided an apparatus for determining the vapor-liquid ratio of a motor fuel comprising an expansion chamber having a top and a bottom and means for supplying a predetermined volume of a sample of said motor fuel to said expansion chamber. Means are also provided which are vertically movable in sealing engagement with the internal walls of said chamber in response to the vapor pressure of said sample for indicating the vapor-liquid ratio of said sample.

In accordance with another aspect of the invention there is provided a method of determining the vaporliquid ratio of a motor fuel, wherein fuel is supplied to an elongated chamber having a top and a bottom and means vertically movable in sealing engagement with the interior of said chamber for indicating the vaporliquid ratio. The method comprises the steps of supplying a predetermined volume sample of the motor fuel at a pressure sufficient to prevent vaporization of the fuel, to one of said top and said bottom when said indicating means is positioned at said one of said top and said bottom, and controlling the vertical movement of said indicating means to provide a predetermined pressure in the portion of said chamber in liuid communication with said sample. Then the amount of vertical movement of said indicating means from said one of said top and said bottom is determined to provide an indication of the vapor-liquid ratio of the sample.

BRIEF` DESCRIPTION OF THE DRAWINGS FIG. l depicts the overall arrangement of the apparatus used in an embodiment of this invention.

FIG. 2 is a sectional view of the rotary valve and connected portions in a lling and draining position.

FIG. 3 shows the rotary valve in a vaporizing position, rotated from the position of FIG. 2.

FIG. 4 is a section through 4-4 of FIG. 3.

FIG. 5 is a section through 5-5 of FIG. 3.

FIG. 6 depicts the use of the vapor-liquid ratio monitor as a control element in the blending of motor fuels.

FIG. 7 is a graph which shows the vapor-liquid ratio of a gasoline at several temperatures, as determined by the methods and apparatus of this invention and the prior art.

FIG. 8 is a schematic representation of another embodiment of the present invention.

FIG. 9 is a sectional view of a valve and valve actuator used in the embodiment of FIG. 8.

FIG. l0 is a schematic representation of a control unit for the embodiment of FIG. 8.

DESCRIPTION OF SPECIFIC EMBODIMENTS Referring to FIG. l, the apparatus of this invention is contained ywithin an insulated housing 1. A sample stream of motor fuel is delivered by a pump 2 through a temperature controlled coil 3, preferably located within the housing, to the sample inlet 4. The sample stream flows to the rotary valve 5, described in detail below, and then to the outlet connector 6 and to the drain apparatus 7, including a back pressure regulator. At this position the valve is positioned so that the previous sample leaves through drain connector 8 to the liquid trap 9 and drain means comprising pressure regulator 10, air regulator 11 and vacuum source 11 The pressure of the sample stream between the pump 2 and the drain apparatus 7 is sufficiently high to prevent vaporization of the fuel in the stream. The temperature controlled coil 3 preheats the fuel in the stream to a specified temperature Which may be the sum of the mean high average temperature for a particular locality and a predicted temperature of an engine under the hood of a car during normal operation.

When the rotary valve is driven by the motor 12` to the vaporizing position, a predetermined volume of the sample is directed into a gas flow calibrator tube 13 which contains vapor-liquid ratio indicating means shown as an piston or mercury sealed float 14. Electrical or photoelectric sensing means 15 generates a signal representative of the position of the oat 14. The tube 13 has a constant internal diameter and is calibrated in volumetric units which are equal to the predetermined volume of the sample to provide a visual readout of the float position and thus a representation of the vapor-liquid ratio of the sample.

The pressure on either side of the oat 14 is equalized in the drain position by the conduit 16. The conduit 16 may be connected to conventional pressure and air regulators 10, 11, which maintain the pressure above the float 14 constant as the oat 14 rises in response to the vapor pressure of the sample. For example, the pressure below the iloat 14 may be -maintained at a value of one standard atmosphere when the rotary valve 5 is in the sample vaporizing position. The pressure above the oat 14 would be equal to one atmosphere minus an amount determined by the weight of the oat 14.

FIGS. 2, 3, 4 and 5 show the rotary valve 5 in greater detail. The valve 5 contains a sample reservoir 17, a drain cup 18 and bypass slot 19. The sample reservoir 17 should be of a known volume to provide the predetermined volurne of the sample, or its volume relative to the volume of the expansion chamber 13 should be ascertained.

In FIG. 2, the drain cup 18 is positioned beneath the calibrator tube 13. At this point the sample will drain through drain means shown as the cup 18- and its associated conduit 40, through sample outlet lmeans shown as the drain connector 8, as indicated by the arrows. The rate at which the sample is drained can be controlled by the t pressure differential created across the seal 14 by the pressure and air regulator 10 and 11. Simultaneously, with the draining of cup 18 the sample reservoir 17 is being llushed and iilled by a sample stream flowing through the sample inlet 4, and associated conduits, to sample reservoir 17 and through stream outlet means shown as the outlet connector 6 and associated conduits as indicated by the arrows.

As depicted in FIG. 3, after a predetermined interval, the motor 11 will turn the valve 5 a suitable distance, illustrated as 120, to position the sample reservoir with the predetermined volume of the sample beneath the calibrator tube 13. At this point the sample will vaporize, and the piston or sealed iloat 14 will rise in the tube 13 to indicate the volume of the vapors to that of the liquid. Simultaneously, the bypass slot 19 will provide a channel for the flow of the sample stream from the inlet connector 4 to the outlet connector 6. Of course, alternative means may be provided to cut oit the supply of sample stream when the valve 5 is in the sample vaporizing position. However, as depicted, the heated sample will help maintain the temperature of the valve 5 and housing 1.

A further feature of the rotary valve 5 is the provision for a thermowell 20 for housing a thermocouple (not shown) for controlling a heating element (not shown) in the vicinity of the coil 3 such that the temperature of the valve 5 and the sample may be maintained at the specied level.

Thus, by this invention a constant-volume sample of motor fuel, such as gasoline, at a controlled temperature is periodically delivered by the rotary valve 5 to the calibrated tube 13. The sample partially vaporizes within the tube 13 to a height indicated by the piston or float 14. The oat 14 can actuate electrical sensing means 1S which provides a direct readout of vapor-liquid ratio. After a reading is obtained, the valve 5 is rotated to a position at which the tube 13 is drained and the sample reservoir 17 is iiushed and filled with a succeeding sample.

FIG. 6 shows an automatic monitoring and blending system in accordance with the invention. A fluid such as a motor fuel flows in a conduit 21 and is monitored by a vapor-liquid ratio monitor 22 as described above. A signal representative of the vapor-liquid ratio of the fluid is applied to a subtractor 23. The signal is generated by conventional electrical (or photoelectrical) sensing means 15 activated by the piston or float 14. Also applied to the subtractor 23 is a reference signal representative of the vapor-liquid ratio at which it is desired to maintain the iiuid. This reference signal may be generated by methods -well known in the art.

The output signal from the subtractor 23 then is representative of the deviation of the vapor-liquid ratio of the fluid from that desired. This signal is applied as an error signal to servo motor 24| which is used to control the setting of a valve 25 that meters the ow of a component, such as butane, for example, for a component source 26 that is allowed to flow into the conduit 211. The Valve 25 is varied until the error signal is reduced to zero, and in this fashion the uid is continuously monitored and is combined with the component to meet a predetermined specication regarding vapor-liquid ratio.

In a specific example, the liquid metering device was a tapered stainless steel plug, one and one-quarter inch in diameter at the center of its longitudinal axis. A half inch diameter hemispheric cup of approximately 0.7 cc. capacity was milled into the plug on the one and one- `quarter inch diameter center line. A drain cup was milled into the plug on the same center line at a angle, counter-clockwise from the sample cup as viewed from the small end of the tapered plug. A drain line was drilled from the bottom of the cupthrough the plug. A bypass slot for the liquid sample was milled into the plug on the same center line at 120 counter-clockwise from the drain cup and drain line. The tapered stainless steel plug was inserted into a Teon sleeve with a matching taper. These were then positioned in a brass lock which mated with the precision bored gas iiow calibrator. The metering de- 'vice was flushed and Ifilled from the position indicated in PIG. 2. The metering device was then rotated 120 to the position indicated in FIG. 3. The pressure below the mercury sealed iioat was maintained at 760 mm. Hg with a nullmatic pressure regulator. The sample used was a premium grade commercial gasoline. The above procedure was followed in a test of several samples which were held at temperatures ranging rorn 120 F. to 134 F. by conventional temperature control apparatus. The position of the float is indicated on the abscissa of the graph in FIG. 7 at each of the respective temperatures indicated on the ordinate of said graph. In the legend these points are indicated as tI.

To verify the accuracy of the method and apparatus of this invention portions of the gasoline sample referred to above were analyzed for their Vapor-liquid ratio by two other methods referred to as the ASTM and Calculated methods (respectively indicated in the legend of FIG. 7 as II and III). In the ASTM method a measured volume of liquid `fuel at 32-40" F. is introduced through a rubber septum into a glycerine-iilled burette. The charged burette is placed in a temperature controlled Water bath. The volume of vapor in equilibrium With liquid fuel was measured at each of the temperatures used above and at the same pressure, 760 mm. Hg. The vapor-liquid ratio was then calculated from the volume displaced by the vapor in the burette and from the initially measured volume of the liquid used. In the calculated method the Reid vapor pressure and the 10, and 50% distillation points were determined for the given sample at each of the above temperatures. 'I'he vaporliquid ratio was estimated from this volatility data by correlations set forth in the prior art, see 1946 CRC Handbook, pages 154 and 155. The results of these tests as indicated in FIG. 7 show that the method and apparatus of this invention may be used to obtain the vaporliquid ratio of a gasoline sample which correlates well with prior art methods.

Another embodiment of the present invention is schematically shown in lFIG. 8. With reference to this figure, a sample stream of the motor fuel, for example gasoline, to be analyzed for vapor-liquid ratio is applied to the system by a sample inlet line 101. The inlet line I101 may be connected to a process line such as line 21 of FIG. 6. 'I'he sample stream ows from inlet line 101 through a metering valve 102 and to a line .107 for application to a temperature controlled coil 109 of a sample preheater 108. The preheater l108 includes an electrical heating element 1-10 for preheatinrg the sample stream to a predetermined temperature, As described hereinabove with reference to the embodiment of FIG. 1, the predetermined temperature may be determined by the sum of the mean high average temperature for a particular locality and a predicted temperature of an engine under the hood of a car during normal operation.

A seperate heater (not shown) may be provided as a source of heat for the elements within an insulated housing .173 to maintain the elements at the predetermined temperature.

From the preheater 108 the sample stream ows through a line 111 to a three-way solenoid valve 112. The three-way solenoid valve 112 is connected by a line 142 to a chromatograph-type sliding plate valve 113 mounted on top of an expansion chamber .114. The expansion chamber 113 comprises a cylinder 115 having a constant internal diameter. A vertically movable piston l116, shown in cross-section, having a sample cup 145 formed in the top thereof is positioned within the cylinder 115. The piston 116 has a pair of O-rings .170, 171 for frictionally engaging the inner surface of the cylinder to ensure that fluids do not pass between the piston 116 and the inner surface of the cylinder 115. The piston 116 and is tixedly secured to the top of a lifting screw 117 of a worm gear screw jack 118 which is mounted at the bottom of the cylinder 115. A suitable jack screw is Simplex Model JMOS, manufactured by Templeton Kenly & Cornpany, Simplex Division, Broadview, Ill.

At the beginning of a vapor-liquid ratio analyzing cycle, the piston 116 is positioned at the top of the cylinder '115 such that the top surface of the piston 116 is flush against the underside of the valve 113. In this position, a

lline 172 extends from the underside of the valve 113 and into the sample cup 145.

The three-way solenoid valve 113 is actuated such that the sample stream flows line 111 through the solenoid valve '1512 to the line 142, through the opened plate valve 113, and through the line -172 into the sample cup 145. From the sample cup 145, the sample stream flows back through the plate valve 113 to a line y143, and another three-way solenoid valve 131 positioned such that the sample stream flows through lines 144, 133, a rotometer 134, lines 135, 137 and to a flow regulator .138. The rotometer 134 is provided to monitor the ow rate of the sample stream. The flow rate of the sample stream is adjusta'ble by the flow regulator 138, which may be a Moore Model 63-SD, manufactured by Moore Products Co., Philadelphia, Pa. The ow regulator 138 has a reference pressure applied thereto by lines 140, `147. In the embodiment of FIG. 8, the reference pressure is atmospheric pressure as schematically represented by line 147 being opened at the lower end thereof. The sample stream of fuel passes through the ow regulator, through an adjustable valve 139, and lines 146, `147 to a drain 141 or to a monitored process line such as conduit 21 of FIG. 6. The ow rate of the sample stream of fuel is maintained at a predetermined level by adjusting the valve 113-9 to provide a predetermined pressure drop across the flow regulator 138.

The pressure of the sample stream of fuel is maintained at a sutiiciently high value to avoid vaporization of the fuel in the stream. A relief valve is connected to line 107 by a line 104 for bypassing a portion of the sample stream to a drain 106 or to return the bypassed portion to a process line such as conduit 21 of FIG. 6. The relief -valve 105 is set to maintain the pressure in the sample stream at a predetermined level as indicated by a pressure gauge 136. For example, the predetermined pressure may be approximately 20 p.s.i.g.

At the end of a predetermined time sui'liciently long to ensure that pressurized Ifuel has lled the sample cup 145, a control unit 124 provides a signal for actuating a three-way solenoid valve to connect a source of pressurized air 175 to a valve actuator 129 by a line 174. The actuator 129 acts to close the sliding plate valve 113 such that lines 142 and 143 are no longer in iluid communication with the sample cup 145. Shortly after actuation of the actuator 129, the control unit 124 provides a signal to the three-way solenoid valve 112 to actuate it to a position such that the sample stream ows from the line 11-1 through the solenoid valve 112, and to the lines 132, 133, the rotometer 134, the lines 135, 137, and to the ow regulator 138.

At this time, the sample cup has a predetermined volume of pressurized sample therein. The control unit 124 then actuates a stepping motor 122 which powers the worm gear screw jack 118 to move the lifting screw 117 downwardly. The lifting screw 117 continues its downward movement until a boss 121 at the lower end thereof engages an arm 148 of a lever 180 to actuate a limit switch 119. The limit switch 119 is positioned a sufficient distance below the screw jack 118 to ensure that the piston 116 is below a sensing element 125. Upon actuation of the limit switch 119, a signal is applied to the control unit 124 which causes the control unit to control the stepping motor 122 in response to the sensing element 125.

The sensing element 125 is a pressure transducer in fluid communication with the interior of the cylinder 115, and may be a transducer model 8503, manufactured by Endevco Laboratories, Mountain View, Calif. The sensing element 125 is positioned a distance down the cylinder to avoid severe exing of the sensing element 125 in response to the pressurized sample of fuel in the sampling cup 145. By the time the piston 116 moves by the sensing element 125, the pressure above the piston 116 has decreased to a value which does not endanger the senssing element 125.

The Endevco transducer model 8503 is capable of providing a signal output which indicates Whether the sensed pressure is above or below a reference pressure. The reference pressure is applied to the sensing element 125 through a line which is connected to a pressure regulator 126. The pressure regulator 126 may be Moore Model 43-20, manufactured by Moore Products Co., Philadelphia, Pa. The Moore Model 43-20 has a source of pressurized air 127 applied thereto which is above the reference pressure. Another source of pressure 128 is also connected to the regulator 126 which is below the reference pressure. The reference pressure is preferably 760 mm. and a suitable value for the pressure source 127 is 5 p.s.i.g. and the pressure source 128 may be a vacuum source. The Moore Model 43-20 has an adjust- 7 able control 151 for providing the predetermined reference pressure in line 150.

In response to signals from the sensing element 125, the control unit acts to cause the stepping motor 122 to drive the lifting screw 117 downwardly if the sensing element senses a pressure above the reference pressure, or to drive the lifting screw 117 upwardly if the sensing element 125 senses a pressure below that of the reference pressure. In this mode, the control unit 124 controls the movement of the lifting screw 117 until the sensing element 125 senses a pressure within the cylinder 115 equal to that f the reference pressure. At this point, the sensing element 125 is at a null point and does not provide an output signal to the control unit 124.

When the sensing element 125 is at its null point, the volume of the space Within the cylinder 115 above the piston 116 measured in units equal to the volume of the sampling cup 145 is the vapor-liquid ratio of the fuel in the sampling cup 145. The cylinder 115 lmay be transparent in whole or in part and graduated in units of volume equal to the volume of the sample cup 145 to provide a visual readout of the vapor-liquid ratio of the fuel in the sample cup 145.

The vapor-liquid ratio of the fuel in the sampling cup l145 may also be recorded or a signal representative of the vapor-liquid ratio will be used to control a process. For example, a gear 154 xedly secured to the outer end of a drive shaft 123 of the screw jack 118 drives a gear 156. The gear 156 in turn positions a movable arm 185 of a potentiometer 157. One end of the resistor portion 186 is connected to a power supply 158 by a line 159, and the movable arm 185 is connected to a recorder 160 by a line 161. The recorder 160 is connected to the power supply 158 by a line 162 to complete the circuit. Thus, the position of the movable arm 185 relative to the resistor 186 is a function of the position of the piston 116 with respect to the underside of the sliding plate valve 113, and thereby is a function of the volume of the space within the cylinder 115 above the piston 116. Therefore, the resistance of the potentiometer 157 as reflected on the recorder 160 is representative of the vapor-liquid ratio of the fuel in the sampling cup 145.

Alternatively, a counter (not shown) may be used to count the number of revolutions of the lifting screw 117, and thus provide a representation of the vertical movement of the piston 116. Further, the potentiometer 157 circuit may provide a signal representative of the vaporliquid ratio of the fuel in the sampling cup 145 to the subtractor 23 of FIG. 6 to thereby control a process.

At the end of a predetermined period of time suiciently long to ensure that the sensing element 125 is at its null point, the control unit provides a signal to the three-way solenoid 131 which places line 143 in uid communication with lines 163, 146 and 147. The control unit also controls the operation of the three-way solenoid valve 130 to connect the source of air 175 with a vent line 176 to thereby remove air from the actuator 129 and permit the sliding plate valve 113 to open. As the lifting screw 117 rises the boss 121 at the lower end thereof engages arm 149 of the lever 180 to actuate the limit switch 119 to remove control of the stepping motor 122 from signals from the sensing element 125. Since the space above the piston 116 is opened to atmosphere via line 143, solenoid valve '131, and lines 146, 147, the liquid in the sampling cup 145 tends to vaporize. The lifting screw continues to rise until the piston 116 is again positioned at the top of the cylinder 115 such that the top surface of the piston 116 ush against the underside of the valve 113. A slip clutch 181 is provided between the motor 122 and the worm gear screw jack 118 to prevent damage to the piston 116 and the valve 113 when the piston has been driven to its uppermost position. At this time, the sampling cup 145 is in a position to receive a new sample from line 111 for test in accordance with the foregoing sequence of events.

vA fail safe switch is provided to remove power from the motor 122 when the lifting screw is driven to an extreme downward position and the boss 121 engages the lever arm of the switch 120.

FIG. 9 shows a valve actuator and sliding plate valve suitable for use as the actuator 129 and valve 113 of FIG. 8. The actuator and valve are available from the Bendix Greenbrier Instruments, Ronceverte, W. Va., and identified by PN 5501334. The reference numerals of FIG. 9 which, are identical to those of FIG. 8 identify items corresponding to those schematically shown in FIG. 8.

The actuator portion comprises a diaphragm 210 secured between plates 211, 212. The diaphragm 210 is :biased to the right by a spring 230 which is mounted about a bolt 231. The bolt 231 secures plates 232, 233 and the center portion of the diaphragm 210 to a movable block 226. The movable block 226 has an O-ring 214 to fluidly seal the block 226 and the plate 212. The block 226 is secured to a movable plate 225 by an extension bar 227. The movable plate 225 is preferably composed of Teflon and includes two parallel ports therethrough for providing a fluid path 'between lines 142 and 172, and 143 and 143. The lines 142, 172, 143 and 143 pass through a pair of plates 215 and 221 which are held together by a bolt and spring arrange-ment 222-224. The sliding plate is secured to a bolt 220 and nut 219. The bolt is movable within a conduit formed in an extension arm 216 which is secured to the plate 215 Iby a nut 217. The bolt 219 is movable about the bolt 220 to provide a space 218 between the nut 219 and the arm 216.

As described with reference to FIG. 8, pressurized air from conduit 174 enters a chamber to exert a force along the right hand side of the diaphragm 210 to move it to the left against the spring 230. This action causes the plates 226, 225 and nut and bolt 219, 220 to move as an integral unit to the left and thereby close the valve. When the source of pressurized air is vented as described with reference to FIG. 8, the spring 230 causes the diaphragm 210, the plates 226, 225 and nut and bolt 219, 220 arrangement to move as an integral unit to the right and thereby open the valve.

FIG. 10 is a schematic representation of a control circuit which is suitable t0 carry out the functions of the control unit 124 described hereinabove with reference to FIG. 8. With reference. to FIG. l0, power is supplied from a source 250 by lines 251, 252 to a pair of ganged switches 253, 154. When the switches 253, 254 are closed power is supplied to the control circuit.

A timer motor 261 is provided to actuate a plurality 0f switches in a predetermined sequence. A suitable speed `:for the motor is 1/10 r.p.m.

To begin the cycle with the piston 116 (FIG. 8) ilush against the underside of the valve 113 (FIG. 8), the timer motor 261 actuates a switch 262 to provide power to a solenoid 269 via lines 280, 281. Actuation of the solenoid 269 moves the three way solenoid valve 131 to the position -which provides a uid path between lines 143 and 144 (FIG. 8). At this time switches 263, 264, 265, and 119 are in the position shown in FIG. 10 and the sliding plate valve 113 (FIG. 8) is in the open position. The timer motor then actuates switch 264 to the position not shown in FIG. l0. This closes a circuit which includes line 280, switch 263, a solenoid 267, and line 281. Actuation of the solenoid 267 causes the three-Way valve 112 to provide a fluid path between lines 111 and 142 (FIG. 8). Thus, iiuid flows to the sampling cup as described with reference to FIG. 8.

After a predetermined time sufficiently long to insure that the sampling cup is filled with pressurized liquid, switch 263 is moved to the position not shown in FIG. 10

and thereby apply power to a solenoid 266 which actuates the three-way valve to connect the source of pressurized air to the valve actuator 129 (FIG. 8)

to thereby close the sliding plate valve 113. Movement of the s-witch 263 to the position not shown in FIG. 10 also removes power from the solenoid 267 to thereby operate the three-way valve 112 to connect line 111 with line 132 of FIG. 8.

The timer motor 261 then actuates a switch 265 to the position not shown in FIG. l to apply power through the limit switch 119 (FIG. 8) to a relay 270. Actuation of the relay 270 closes a drive down switch 274 which completes a circuit to an amplifier 272 which consists of switch 282 in the position shown, a resistor 276y and a switch 273 in the position shown. Completion of this circuit causes the motor 122 of FIG. 8 to drive the lifting screw 117 (FIG. 8) downwardly.

As described with reference to FIG. 8, the limit switch 119 is actuated by the boss 121 to the position not shown in FIG. 10. This actuation of switch 119 applies power to a relay 271 which in turn causes the switches 273 and 282 to move to the position not shown in FIG. 10. This places the motor 122 under the control of the sensing element 125 (FIG. 8) which includes the block circuit 277. As described hereinabove, the sensing element may be Endevco Model 8503. The circuit portion 277 of the sensing element 125 (FIG. 8) has power applied thereto by lines 280 and 28.1. The circuit portion 277 then controls the motor 122 until the sensing element 125 (FIG. 8) is at a null point.

At the end of a predetermined time sufficiently long to insure that the sensing element 125 is at a null point, .the timer motor 261 actuates switch 262 to the position shown in FIG. to thereby deenergize the solenoid 269 and move the three-way valve 131 to a position which connects line 143 to line 163 of FIG. 8. The timer motor 261 then operates switches 263 and 264 to the position shown in FIG. l0. This removes power from the solenoid 266 which causes the three-way valve 130 to vent the source of pressurized air 175 by line 176 (FIG. 8). Thus, the sliding plate valve 113 (FIG. 8) is opened.

Movement of switch 263 to the position shown in FIG. 10 also removes power from the relay 271 to thereby cause the switches 273, 282 to move to the position shown in FIG. l0. When switches 263 and 264 are in a position shown in FIG. 10, power is supplied to a relay 268 which operates to close a drive up switch 275. Closure of the drive up switch 275 completes a circuit to the amplifier 272 which includes switch 282, resistor 276, switch 275 and switch 273. This circuit causes the amplifier 272 to provide an output signal which operates the motor 122 to drive the lifting screw upwardly. As the lifting screw moves upwardly, the limit switch 119 is actuated by the boss 121 at the end of the lifting screw (FIG. 8) to move the limit switch 119 to the position shown in FIG. 10.

The timer motor 261 also operates to move the switch 265 to the position shown in FIG. 10. This mode is continued for a sufliciently long time to insure that the lifting screw returns the piston 116 to a position ush against the underside of the valve 113 (FIG. 8). Since the sample in the sampling cup 145 is in fluid communication with the atmosphere by way of the opened sliding plate valve 113, the line 143, the three-way solenoid valve 131, and lines 163, 146 and 147, (FIG. 8), the sample tends to vaporize as the piston 116 rises. The slip clutch 181 (FIG. 8) is provided to avoid damage to the apparatus after the piston 116 engages the underside of the valve 113.

At this time the system is ready to repeat the foregoing sequence of events to determine the vapor-liquid ratio of a new sample.

The circuit of FIG. 10 also includes a fail-safe network which comprises a bottom limit switch 257 which corresponds to the bottom limit switch 120 of FIG. 8 and which is normally in the position shown in FIG. 10. However, should the boss 121 (FIG. 8) at the lower end of the lifting screw 117 actuate the bottom limit 257 it is moved to the position not shown in FIG. 10. Movement of the switch 257 to the position not shown applies power to a relay 260 which opens the normally closed switch 258 and applies power to a lamp 257' to give an indication of the problem. This action removes the power at line 280 from the timer motor 261. Further, movement of the switch 257 to the position not shown removes power from the motor 122 and thereby stops the movement of the lifting screw 117 (FIG. 8). An interrupt switch 255 is closed for a substantial portion of the cycle under the control of the timer motor 261. Thus, power is applied to the timer motor 261 even though the switch 258 has been opened. This permits the timer motor 261 to continue operation until it reaches a predetermined point in the program, at which time the interrupt switch 255 is opened.

A reset button 256 is provided to restart the timer motor 261 after the system has been stopped as a result of actuation of the bottom limit switch 257. The reset button 256 is depressed to provide a circuit therethrough to the timer motor 261 until at least the timer motor 261 causes he interrupt switch 255 to close, and preferably, until the lifting screw 117 is driven upwardly until the boss 122 actuates the bottom limit switch 120 to move the switch 257 to the position shown in FIG. 10. This causes the relay 260 to deactivate and to close switch 258 to provide power from line 280 to the timer motor 261.

Thus, there have been described specific embodiments for determining the vapor-liquid ratio of a fuel, and for controlling a blending operation in response to the monitored vapor-liquid ratio. It will be understood by those skilled in the art that the above-described embodiments are merely exemplary and that they are susceptible to modification and variation without departing from the spirit and scope of the invention.

What I claim is:

1. Apparatus for determining the vapor-liquid ratio of a motor fuel comprising:

an elongated expansion chamber having a first end and a second end opposite said iirst end,

means for supplying a predetermined volume of a sarnple of said motor fuel to one of said first end and said second end, means longitudinally movable in sealing engagement with the internal walls of said chamber for indicating the vapor-liquid ratio of said sample, and

means connected to said indicating means for moving said indicating means in response to the vapor pressure of said sample.

2. Apparatus for determining the vapor-liquid ratio of a motor fuel comprising:

an expansion chamber having a top and a bottom,

means including a sample receptable for positioning a predetermined volume of a sample of said motor fuel in sealing engagement with said top, and

means vertically movable in sealing engagement with the internal walls of said chamber in response to the vapor pressure of said sample for indicating the vapor-liquid ratio of said sample.

3. The apparatus of claim 2 further comprising means for sensing the position of said vapor-liquid ratio indicating means and for generating a signal representative of the vapor-liquid ratio of said sample.

4. Apparatus for determining the vapor-liquid ratio of a motor fuel comprising:

an elongated expansion chamber having a top and a bottom, receptacle means vertically movable within said chamber and in sealing engagement with said chamber for receiving a predetermined volume of said fuel,

valve means for supplying a pressurized sample of said fuel into the top of said chamber to said receptacle means, and for exhausting said sample from said chamber,

means for sensing the pressure within said chamber,

and

control means responsive to said sensing means for vertically moving said receptacle means until the pressure within said chamber above said receptacle means is at a predetermined value.

S. The apparatus of claim 4 wherein said sensing means is positioned a suflcient distance from the top of said chamber to prevent damage thereto by the pressurized sample, and wherein said control means sequentially performs the following functions:

(a) vertically move said receptacle means to the top of said chamber,

(b) actuate said valve means to supply a pressurized sample of said fuel to said receptacle means,

(c) actuate said valve means to seal the top of said chamber,

(d) vertically move said receptacle means downwardly to a position below said sensing means,

(e) vertically move said receptacle means in response to said sensing means until the pressure Within said chamber is at the predeterminde value,

(f) actuate said valve means to provide an exhaust for said sample, and

(g) vertically move said receptacle means upwardly to exhaust said sample through said valve means.

6. The apparatus of claim 5 further comprising means for determining the distance between the top of said chamber and said receptacle means when the pressure Within said chamber is at the predetermined value to provide an indication of the vapor-liquid ratio of said sample.

7. Apparatus for blending a motor fuel having a predetermined vapor-liquid ratio, wherein a plurality of components including at least one component which affects the vapor-liquid ratio of the motor fuel are combined in blending means, comprising:

the apparatus of claim 4,

means for generating in response to the vertical movement of said receptacle means a signal representative of the vapor-liquid ratio of said sample,

means for generating a signal representative of said predetermined vapor-liquid ratio,

means for generating an error signal representative of the difference between the sample vapor-liquid ratio signal and the predetermined vapor-liquid ratio signal, and

means for controlling the relative amount of said one component in the blending means in accordance with the magnitude of said error signal.

8. Apparatus for blending a motor fuel having a predetermined vapor-liquid ratio, wherein a plurality of components including at least one component which affects the vapor-liquid ratio of the motor fuel are combmed in blending means, comprising an expansion chamber having a top and a bottom,

valve means for positioning a sample of predetermined value of said motor fuel in sealing engagement with said expansion chamber top,

conduit means for delivering a stream of the motor fuel from the blending means to said valve means,

means vertically movable in sealing engagement with the internal walls of said chamber in response to the vapor pressure of said sample for indicating the vapor-liquid of said sample,

means for generating in response to the vertical movement of said vapor-liquid ratio indicating means a signal representative of the vapor-liquid ratio of said sample,

means for generating a signal representative of said predetermined vapor-liquid ratio,

means for generating an error signal representative of the difference between the sample vapor-liquid ratio signal and the predetermined vapor-liquid ratio signal, and

means for controlling the relative amount of said one 12 component in the blending means in accordance with the magnitude of said error signal.

9. A method of determining the vapor-liquid ratio of a motor fuel, wherein fuel is supplied to an elongated chamber having a irst end and a second end opposite said first end, and means longitudinally movable in sealing engagement with the interior of said chamber for indicating the vapor-liquid ratio, comprising the steps of:

supplying a predetermined volume sample of the motor fuel, at a pressure sufficient to prevent vaporization of the fuel, to one of said first end and said second end when said indicating means is positioned at said one of said first end and said second end,

controlling the longitudinal movement of said indicating means to provide a predetermined pressure in the portion of said chamber in fluid communication `with said sample, and

determining the amount of longitudinal movement of said indicating means from said one of said iirst end and said second end to provide an indication of the vapor-liquid ratio of the sample.

10. A method of determining the vapor-liquid ratio of a motor fuel comprising the steps of:

conveying a sample of predetermined Volume of the motor fuel to means for determining vapor-liquid ratio,

moving said sample to the top of an elongated expansion chamber of said vapor-liquid ratio determining means thereby causing vertically movable means in sealing engagement with the internal Walls of said chamber to move in response to the vapor pressure of said sample for indicating the vapor-liquid ratio of said sample.

controlling the vertical movement of said vapor-liquid ratio indicating means to provide a predetermined pressure afbove said vapor-liquid ratio indicating means, and

measuring the vertical movement of said vapor-liquid ratio indicating means to determine the Vapor-liquid ratio of said sample.

11. A method of blending a motor fuel having a predetermined vapor-liquid ratio, wherein a plurality of components including at least one component which aifects the vapor-liquid ratio are combined in blending means, comprising the steps of:

at least substantially continuously flowing a stream of the motor fuel from the blending means to means for determining vapor-liquid ratio;

obtaining .a sample of predetermined volume from the motor fuel stream;

moving said sample to the top of an elongated expansion chamber of said vapor-liquid ratio determining means thereby causing vertically movable means in sealing engagement with the internal walls of said chamber to move in response to the vapor pressure of said sample for indicating the vapor-liquid ratio of said sample;

controlling vertical movement of said vapor-liquid ratio indicating means to provide a predetermined pressure above said vapor-liquid ratio indicating means; generating, in response to vertical movement of said vapor-liquid ratio indicating means, a signal representative of the vapor-liquid ratio of said sample;

generating a signal representative of said predetermined vapor-liquid ratio; generating an error signal representative of the difference ibetween the sample vapor-liquid ratio signal and said predetermined vapor-liquid ratio signal; and

controlling the relative amount of said one component in the blending means in accordance with the magnitude of said error signal.

(References on following page) 13 14 References Cited 3,145,561 8/ 1964 Thompson 73-64.2 UNITED STATES PATENTS 3,276,460' 10/ 19616 Feld 137-3 51; gafvey- 73 53 WILLIAM F. ODEA, Primary Examiner 6 e-lnz- 5 D. I. Assistant EXamiller 7/ 1962 Nakata. 9/1963 Dye 73-64.2 US C1' X'R' 1/1964 Weir. 73-61.3, 64.2, 308; 137-88 Tg5/gg? UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Parent No. 3,528,1um Dated 'september 15, 1970 lnvenwdww III It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, at line 60, for "11" read l2 Column 5,' at line 43, for "113" read 11k-n; at line 62, for "113 read 112; at line 63, after "flows" insert fron. Column 7 at line 68* after l'11.6" insert -1s. Column 8, at line 1'49, for "15u read "2514". column 1o, at 11ne- 2o, for "he" read -the; et line 52, for "recegtable" read receptacle. Column 11, at line 20, for predeterminde read predeterm1ned; at line 56, for "value" read --volume--g at line 63, after "liquid" insert --ra.tio.

SIGE) ND Q EME?? NW 2'. M910 (SEAL) hulnahnlr- L Amngofm Oomnnxw of Patents

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