FR2665743A1 - NON-RETURN VALVE FOR A GAS CONDUIT. - Google Patents

Abstract

Known non-return valves intended in particular to suck secondary air into the exhaust system of internal combustion or internal combustion engines in order to reduce the content of harmful materials in the exhaust gases have the disadvantage of having a tendency, even if the secondary air supply is stopped, to be noisy because their shutters are caused to vibrate under the effect of the pulsations of the exhaust gases. The non-return valve according to the invention avoids this drawback and is distinguished by the fact that a limiting element (16) can be moved by a pneumatic operating mechanism (10) (or electric) in the direction of the shutter and maintains the shutter (15) in the closed position in the event of a stoppage of the secondary air supply.

Description

i Non-return valve for a gas pipe

  The present invention relates to a check valve.

  return for a gas pipe, especially for a

  duct intended to bring secondary air into a system

  exhaust of an internal combustion or internal combustion engine, the valve being equipped with a valve seat plate which has one or more passages for the

  fluid to direct, and at least one shutter.

  Non-return valves of this kind are used

  to reduce the content of harmful substances in

  exhaust In this respect we take advantage of the known phenomenon

  which is that the pressure in the exhaust pipes

  periodically, so that at intervals

  determined time intervals occur in the system

  exhaust pressures below atmospheric

  risk To suck in air, check valves are used

  such return (secondary air suction valves) which open when prevailing in the exhaust system

  pressure below atmospheric and will

  at higher than atmospheric pressure, so that burnt gases cannot escape to

  the exterior Due to the air thus brought to the exhaust gases

  pement there occurs in the exhaust system a

  oxidation reaction so as to reduce the hydro-

  carbides (CH) and carbon monoxide (C 0) exhaust gases

  pement. These non-return valves are also frequently used in combination with air pumps in the case of exhaust systems fitted with regulated catalysts, mounted downstream In this case it is mainly in

  the warm-up phase, during which

  in a known manner a rich mixture, only secondary air

  re is brought to the hot exhaust gases so as to

  hold an afterburner, so that on the one hand the

  CO and CH constituents in the exhaust gases are reduced by approximately 30% and on the other hand the catalyst which is not yet active is brought more quickly to its temperature

  of entry into action As soon as the entry temperature into ac-

  tion is reached the secondary air supply is interrupted

  stinks This is done for example by means of a shut-off valve

  separate top which, mounted in the air supply duct,

  fixed and actuated by pilot pressure, is controlled

  ded by means of a reversing solenoid valve

added.

  In Pierburg's publication "AGR-

  Ventile, SLS-Ventile ", registration number 5 / 400-150 2, describes a secondary air suction valve in which the shut-off valve and the non-return valve are grouped in a valve body, an inverting solenoid valve being

  here also necessary for ordering In this regard an in-

  suitable is that non-return valves of this

  kind tend, even if the secondary air supply stops

  daire, to make noise since their shutters are soul-

  born to vibrate due to the pulsations of exhaust gases to which they are subjected In addition, this results in a

  increased wear and tear at the expense of their resistance to fatigue.

  Starting from this state of the art, the pre-

  sente invention aims to achieve a check valve

  turn of the kind mentioned above in such a way that the disadvantages mentioned are avoided as far as possible. This object is achieved according to the invention, as regards a non-return valve for a gas pipe, in

  in particular for a duct intended to supply dry air

  in an exhaust system of an internal combustion engine

  or internal combustion, the valve being equipped with a

  valve seat plate, which has one or more

  at least one passages for the fluid to be directed, of at least one

  turator, a spring element and a limiting element, in that the limiting element can be moved by a

  operating mechanism in the opening or closing direction

  shutter lock and locks or unlocks the shutter

turator.

  In an advantageous embodiment of the

  non-return pet according to the invention the operating mechanism is produced as a pneumatic regulator which can be subjected by means of a control valve

at pilot pressure.

  In another advantageous embodiment

  of the non-return valve according to the invention the mechanism of ma-

  noeuvre consists of an electromagnet.

  An advantageous feature of the check valve

  return of the invention still consists in that the shutter-

  the spring element and the limiting element are

  sés either in a form with symmetry of revolution, or in

ribbon shape.

  The non-return valve according to the invention is

  tinguished by the fact that the limiting element can be moved by a pneumatically operated operating mechanism or

  electric in the direction of the shutter, so that the

  turbine made in a form of symmetry of revolution or in the form of a ribbon is, in the event of a stop of secondary air supply, locked in the closed position, i.e. it is no longer caused to vibrate and therefore to

  be noisy under the effect of the exhaust gas pulsations

  In addition, the service life of the check valve

return is thus extended.

  Another advantage is that in the case

  of the electrically operated operating mechanism, unlike

  of the pneumatic operating mechanism, the control

  the secondary air supply stop is carried out directly-

  so that one can dispense with an electroval-

  ve reversing to act or interrupt the pilot pressure. Two embodiments of the invention are

  described below and shown diagrammatically below

  attached sins in which: Figure 1 shows a non-return valve in section; and Figure 2 shows, in section, another shape

  for making a non-return valve.

  FIG. 1 shows a non-return valve 1 which, constituted by an upper part 2 of the valve body with an inlet connection 3 for the supply of secondary air, and by a lower part 4 of the valve body with a outlet connection 5, comprises a plate 7 forming a valve seat and a stroke limiter 8 each mounted, between the upper part 2 and the lower part 4 of the body

  valve, in an elastomer ring 6 for sealing purposes

  body vibration damping, the plate 7 forming the valve seat having several passages 9 for the fluid to be directed The upper part 2 of the valve body is produced as a pneumatic regulator which, by means of a control connection 11, can be subjected by means of an inverting solenoid valve (not shown in the figures) to a pilot pressure and comprises an actuating bar 14 connected to a membrane

  13 acting against a spring 12.

  The actuating bar 14 passes through the plate 7 forming a valve seat and a shutter 15 cooperating with the latter and has a limiting element 16 and a

  spring element 17 fixed at its end located at the oppo-

membrane 13.

  The shutter 15, the limiting element 16 and the element

  spring 17 are produced in a form with symmetry of revolution, but it is also conceivable to provide

  ribbon-shaped embodiments.

  In the example of embodiment of a check valve

  return shown in FIG. 2 the function of the pneumatic regulator is fulfilled by an electromagnet 18 mounted in the upper part 2 of the valve body and constituted by

  a coil 19, which is supplied with current by means of

  diary of electrical conductors 20 and 21, by a core 22

  and a frame 23 to which the action bar is fixed-

  14 with the limiting element 16 and the spring element 17 All the other constituent elements correspond to

those of figure 1.

  The operating mode of the valve according to the

  vention is described below If it prevails at rac-

  control cord 11 of the non-return valve 1 according to FIG. 1 a pressure lower than that of the atmosphere, then the diaphragm 13 moves with the actuating bar 14 and the limiting element 16 fixed at the end of the latter, against the force of the spring 12, in the direction of the stroke limiter 8 so that the spring element 17, which guides the shutter 15 axially and radially, relaxes and that as a result the shutter 15 is unlocked The non-return valve 1 now operates in the known manner, from the sucked secondary air which can flow through the passages 9 from the shutter 15 to the outlet 5 and from there into the exhaust system d '' a motor

internal combustion.

  When the operating temperature of the mo-

  tor and catalyst is reached the control fitting 11 is supplied with air and the diaphragm 13 is pushed with the actuating bar 14 and the limiting element 16 fixed to the latter as well as the spring element 17, by the force of the spring 12, in the direction of the plate 7 forming the valve seat, so that the shutter 15 is firmly applied to the plate 7 forming the valve seat and is

  locked in this closed position.

  The check valve of Figure 2 operates on the same principle; deprived of current, it is closed from

  made by the force of the spring 12, that is to say that the shutter-

  tor 15 is held in place by the limiting element 16.

  When the electromagnet 18 is supplied with current, the actuating bar 14 connected to the armature 23 unlocks the shutter 15 and secondary air can flow through the valve, as already described above, in the

exhaust pipe.

Claims (4)

  1 non-return valve for a gas pipe, in particular for a pipe intended to bring secondary air into a flue gas exhaust system of an internal combustion or internal combustion engine, the valve being provided with a valve seat plate which has one or more passages for the fluid to be directed, at least   a shutter, a spring element and a limiting element   tor, characterized in that the limiting element (16) can be moved by an operating mechanism (10, 18) in the opening or closing direction of the shutter (15) and   locks or unlocks the shutter.   2 check valve according to claim 1, characterized in that the operating mechanism is produced   as a pneumatic regulator (10) which can be supported   brought to pilot pressure via a valve control.   3 check valve according to claim 1, characterized in that the operating mechanism is formed an electromagnet (18).   4 check valve according to any one of   previous claims, characterized in that the obtura-   tor (15), the spring element (17) and the limiting element (16) are produced in a form with symmetry of revolution or in the form of a ribbon.