FR2460473A1 - VOLUMETRIC COUNTER WITH MOBILE PARTS - Google Patents

Abstract

THE INVENTION RELATES TO A VOLUMETRIC METER WITH MOBILE PARTITIONS. THE METER IS EQUIPPED WITH A DEVICE DETECTING THE MOVEMENTS OF ITS PARTITIONS, GENERATED BY THE LIQUID TO BE MEASURED, AS WELL AS A DEVICE TO COMPENSATE THE DEVIATIONS DUE TO THE CONSTRUCTION AND THE ENVIRONMENTS. TO OBTAIN A SIMPLE AND RELIABLE COMPENSATION, AN ELECTRONIC COMPUTER IS CONNECTED DOWNSTREAM OF A PULSE GENERATOR, THIS ELECTRONIC COMPUTER INCLUDING AN ADJUSTMENT DEVICE FOR A CORRECTION FACTOR TAKING ACCOUNT OF THE SAID DEVIATIONS. PREFERREDLY, AT LEAST ONE PULSE GENERATOR IS MOUNTED IN THE WET CHAMBER OF THE MEASURING DEVICE. APPLICATION TO VOLUMETRIC MEASURING DEVICES, IN PARTICULAR GASOLINE PUMPS.

Description

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  The present invention relates to a volumetric counter-

  movable partition, designed to measure quantities of

  fluids and fluids and equipped with a device for detecting

  displacement keys of said partitions due to the liquid to be measured, as well as a compensation device for the deviations

  measurement mechanism, due to the construction and the

  places. For many decades, various embodiments of volumetric meters for measuring quantities of liquids and comprising partitions have been known.

  mobile. To distribute the liquid fuel in

  services. the most common volumetric meters are

  counters with several pistons, preferably four.

  In all the embodiments of these counters, the smallest deliverable quantity corresponds to at least one displacement cycle of the measuring mechanism which is driven by the

  pressure of the liquid to be measured and in turn

  display mechanism, said measuring and display mechanisms

  constituting said volumetric counter.

  In order to compensate for the deviations of the measuring device, both those due to the construction and those resulting from the medium, while taking into consideration the legal requirements for calibration, two different methods are known. In one of these methods, the measurement chamber, constituted by one or more moving partitions, is adjusted according to the set volume, once the difference between the measured value and said setpoint volume is known.

  after the complete assembly of the components constituting the

  volumetric converter. This adjustment of the measuring chamber is ensured either by a grinding of members constituting the measuring device, or by a correction of the stroke of at least one movable wall. For this purpose, in multi-piston counters most often used in practice, adjustable stops are provided to modify the stroke of at least one of said pistons mounted with a predetermined clearance. In addition, there are embodiments in which the adjustment of the measuring chamber according to the set point

  takes place via additional auxiliary pistons

  tary. However, in all cases, complicated manufacturing

  It is necessary and costly, as well as an adjustment which, obtained by several measurement processes and requiring a large workforce, necessarily involves interventions on said measuring chamber. Moreover, the adjustment devices necessary to adjust this measuring chamber are subject to wear, so that, after a certain time,

  measurement controls and, where appropriate, other regulators are required.

  The second method of compensating for deviations from

  measurement system, due to the construction and the media, includes a correction by means of an intermediate mechanism interposed between the measuring device and the display device, which, while maintaining the deviation noted-by a calibration in

  the measuring chamber, correct the error by means of a

  adjustable gear system, so that the mechanism of

  associated record only shows the actual measured volume

  by the measuring device under consideration. These inter-

  intermediaries between the measuring device and the

  positive display of the volumetric counter also imply

  not only a complicated embodiment, but they also require the presence of a drive shaft exiting the wet chamber of said measuring device. This driving shaft requires the presence of a sealing element which, on the one hand, constitutes an additional complication of embodiment and, on the other hand, because of its inevitable friction, causes an offset during the measuring process.

  which adversely affects the accuracy of this

  Niere. Whereas, according to the first method, the measuring chamber adjusted according to the setpoint allows universal use of the measuring device, irrespective of the display device, a volumetric meter set according to the second method, by means of an intermediate mechanism, requires a securing of a measuring device to the associated display device by said intermediate mechanism. In this way, this second method also comprises

  disadvantages, since the setting of the multiplier

  cation of said intermediate mechanism, involving an exchange of pairs of gears, requires a complicated assembly and a considerable loss of time. The present invention therefore relates to a correction device which, intended to compensate for deviations (due to the construction and the media) of the measuring device, operates smoothly and can be easily corrected, in order to take account, when the display of the difference found in

the unmodified measuring chamber.

  According to the essential features of the invention,

  an electronic computer is connected downstream of a gen-

  pulse generator delivering a predetermined number of pulses

  per trip cycle, this electronic calculator

  comprising an adjusting device for a correction factor

  taking into account differences due to construction and the environment.

  While avoiding the use of

  wear jets, as well as interventions on the wet chamber of the measuring device necessitating the presence of additional sealing zones, the invention therefore proposes a device which, with few components, allows a continuous compensation of the differences due to the construction and the media, without the need to intervene on the wet chamber of said measuring device after calibration, and without requiring, during the manufacture of the measuring chamber, large specifications increasing the costs. Since this compensation device according to the invention is a component of the measuring device, it is possible to dispense not only with the sealing element of the shaft between the measurement and display devices, which is necessary in the forms of known realization, but also of the association,

  until now necessary, a display device de-

  mined with a special measuring device.

  According to another characteristic of the invention, at least the pulse generator of the compensation device is mounted in the humid chamber of the measuring device, so that this humid chamber can be permanently hermetically sealed without loss of time after the first one. single mounting, and that said measuring device is connected to the

  display device only through a conductive

pulse generator.

  The invention will be described in more detail with reference to the accompanying drawings by way of non-limiting example and in which: FIG. 1 is a longitudinal section of a volumetric meter in the form of a piston meter and provided with a compensation device; Figure 2 is a block diagram of said compensation device; and

  Figure 2a shows schematically the volumetric meter.

  The volumetric meter illustrated as an exemplary embodiment has a housing 1 in which four pistons

  2 are moved in respective jackets 3 of cylinders.

  These pistons 2 are secured in pairs by means of respective crossed moving elements 4, the directions of movement of the two

  pairs of pistons in a common plane being

  cular. The two movable elements 4 / intersecting at right angles, two pairs of pistons each comprise an oblong hole in which is housed a roller 5. The two rollers 5 are mounted so as to rotate on the crank pin 6 of a crankshaft 7 , whose ends are in turn mounted in the casing 1 so as to rotate. Each of the cylinders constituted by the shirts 3 housing the four

  pistons 2. is closed by a cylinder head 8. In each of the

  8, opens a channel 9 formed in said housing 1.

  A rotary slide 10, cooperating with these channels 9

  is fixed on the crankshaft 7 and mounted in a solid body

  said casing 1. This body 11 has an admission channel

  13 and an outlet channel 12 of the liquid whose flow is measured. This pressurized liquid enters the body 11 in the direction indicated by the arrow in FIG. 1, and from there,

  runs through the drawer 10 and one of the channels 9.

  From this channel 9, the liquid then arrives, in

  a cylinder head 8, in the cylinder 3 considered, in which it pushes the associated piston 2 towards the center of the housing 1. Since said piston 2 is secured by its movable member 4 to the piston 2 which is coaxial with it, the displacement of one of the pistons 2 by the liquid causes an evacuation of the liquid in the cylinder 3 of the piston 2 displaced, the liquid flowing through the cylinder head 8 and entering the channel 9 considered then from there ends in the outlet channel 12 after having gone through the drawer 10. This process is repeated

  cyclically for the four cylinders 3.

  The displacement of the pistons 2, which takes place during the cycle

  of work is transmitted through the mobile organs

  the 4 and the rollers 5 at the crank pin 6 of the crankshaft 7, this crankshaft thereby effecting a rotation of 3600 for each work cycle. The volume of the liquid discharged during this rotation of 3600 corresponds to the volume of the chamber of

  measurement of the volumetric meter equipped with four

  biles, and at the same time constitutes the minimum quantity

of liquid to be discharged.

  The crankshaft 7, which protrudes upward out of

  housing 1 and enters the body 11, supports a rotatable drawer

  tif 10 beyond which it extends. At its end protruding from said drawer, this crankshaft 7 supports a pulse disk 14 which, as shown in FIG. 1, is mounted

  in the wet chamber of the measuring device, and more

  This disk 14 is a component of a pulse generator 15 which is more prominently highlighted.

  by the block diagram in Figure 2. Downstream of this gen-

  pulse generator 15, is connected an electronic calculator

  whose components are also visible in Figure 2.

  According to the embodiment illustrated in FIG. 2, the electronic computer comprises an adjustment device 16 for a correction factor taking into account the differences due to the construction and the media, a signal processing device 17, as well as, connected downstream, a signal transmitter 18 and a counter 19. The components 15 to 19 are connected to a supply device 20 and they control a display device 21 which, in the example

  illustrated, presents in all five figures.

  The disk 14 generates in the generator 15 a number

  determined pulses for each work cycle. This means

  that at each impulse corresponds a determined quantity of the liquid discharged by the volumetric meter. If, during calibration of the piston meter, it turns out that the volume measured per pulse does not correspond to the set volume, the difference separating the actual volume from said set volume is measured, then is calculated a factor of correction by which the number of pulses per working cycle must be multiplied in order to compensate for the deviations of the measuring device of said

  piston meter, due to construction and environments.

  This correction factor is introduced into the adjustment device 16 and, for this purpose, the latter is equipped with a control member 16a. Preferably, this member 16a is connected to the

  device 16 only by a pulse driver.

  The pulses delivered by the generator 15 according to

  of the work cycle are thus transmitted in a modified form.

  It is connected by the adjusting device 16 to a signal processing device 17, the latter delivering corrected pulses by means of the emitter 18 connected downstream. Finally, these pulses delivered by the transmitter 18 and taking into account the deviations of the measuring device, due to the construction and the

  mediums, reach the counter 19 which controls the

  As a result, this device 21 displays the

  volume of liquid actually measured by the pis-

  the measuring chamber of this meter has been set according to the setpoint and without

  complicated intermediary mechanism is necessary.

  In FIG. 2a, the counter having the pistons 2 and the

  shirts 3 and the crankshaft 7 are shown schematically.

  matically. As is apparent from Figure 1, the pulse generator 15 is included in a block 22 of molded plastic material which is housed in a recess of the body 11 of the drawer. This plastic block 22 housed in the wet chamber of the measuring device encloses at least said generator 15; it can also contain other components of the electronic computer, up to and including the counter 19. In this case, the volumetric meter can cooperate, in the form of a unitary assembly, with any display device

  21, with which it must be connected by only one

pulse generator 23.

  It goes without saying that many modifications can be made to the volumetric meter described and shown,

  without departing from the scope of the invention.

Claims (2)

  1. Movable partition volumetric meter for measuring quantities of liquids or fluids and equipped with   detecting the movement cycles of said partitions, generating   by the liquid whose flow must be measured, as well as an apparatus for compensating for the deviations of the measuring device due to the construction and the media, characterized in that an electronic computer is connected downstream of a generator ( 15) delivering a determined number   pulses per cycle of displacement, this electronic calculator   device comprising an adjusting device (16) for a correction factor taking account of deviations due to the construction and the media: 2. Counter according to claim 1, characterized in that at least the pulse transmitter (15) is mounted in the   humid chamber of the measuring device.