Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
  • F16K47/00—Means in valves for absorbing fluid energy
  • F16K47/02—Means in valves for absorbing fluid energy for preventing water-hammer or noise
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
  • F16K15/00—Check valves
  • F16K15/02—Check valves with guided rigid valve members
  • F16K15/025—Check valves with guided rigid valve members the valve being loaded by a spring
  • F16K15/026—Check valves with guided rigid valve members the valve being loaded by a spring the valve member being a movable body around which the medium flows when the valve is open
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B1/00—Engines characterised by fuel-air mixture compression
  • F02B1/02—Engines characterised by fuel-air mixture compression with positive ignition
  • F02B1/04—Engines characterised by fuel-air mixture compression with positive ignition with fuel-air mixture admission into cylinder
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T137/00—Fluid handling
  • Y10T137/7722—Line condition change responsive valves
  • Y10T137/7738—Pop valves
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T137/00—Fluid handling
  • Y10T137/7722—Line condition change responsive valves
  • Y10T137/7837—Direct response valves [i.e., check valve type]
  • Y10T137/785—With retarder or dashpot
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T137/00—Fluid handling
  • Y10T137/7722—Line condition change responsive valves
  • Y10T137/7837—Direct response valves [i.e., check valve type]
  • Y10T137/7904—Reciprocating valves
  • Y10T137/7922—Spring biased
  • Y10T137/7927—Ball valves
  • Y10T137/7928—With follower

Definitions

• the invention relates to a check valve according to the preamble of Patent Claim 1.
• a solution for preventing clattering check valves is shown in American patent US,A,3,782,412.
• a cylindrical valve head runs in a narrow circular throughflow channel so that only a narrow gap is formed between the valve head and the channel.
• the cylindrical valve head is plane-machined on its outer surface in only three places of four generatrices distributed evenly over the circumference, a lateral force is brought about on the valve head towards the channel wall in the event of developed flow. Consequently, the valve head adheres against the wall so that small flow fluctuations do not cause the valve head to strike down against the valve seat.
• valve head has a first sealing body in the form of a rounded elastic valve head which allows deformation of the valve head until a more rigid collar downstream on the valve head comes into contact around the valve seat.
• valve head of a check valve is conventionally designed as a sphere or hemisphere in order to reduce the low resistance overthe check valve, this means that a small flow fluctuation can cause a rapid movement of the valve head towards the seat.
• the valve head can to a certain extent be made elastic and shock-absorbing, but such a design does not reduce the speed of the valve head upon movement towards the seat, as a result of which noise can still arise.
• valve head in check valves in injection systems for petrol engines, the valve head must be resistant to petrol, which means that relatively rigid rubber material must be used in the first instance.
• This rigid rubber material affords good sealing but, as far as noise generation is concerned in the event of striking against the valve seat, the noise reduction is small.
• the object of the present invention is to provide an improved quiet check valve with low pressure drop, which is suitable for pulsating flow, especially as a check valve in an injection system for fuel for Otto engines.
• injection systems often include a check valve which is to ensure that the fuel is retained in the pipes and is not drained back to the fuel tank when the engine is switched off.
• the check valve has a ball-shaped or spherical valve head which affords low pressure drop and has a characteristic which affords rapid response to the flow and its fluctuations, the valve head of the check valve comes to strike back against the valve seat at high speed and cause the valve head to end up in a state of self-oscillation. This self-oscillation is evident in the idle speed of the combustion engine, and lies around 1000 Hertz depending on the spring characteristic of the check valve.
• check valve according to the invention is characterised by the features which are indicated in the characterising part of the main claim.
• the invention results in the valve head being forced, with developed flow, to take up a position at a distance from the valve seat and, with developed flow, a volume of fluid between the flange and the valve seat being used as damping fluid for the movement of the valve head towards the valve seat. Consequently, the spherical valve head can lie and self- oscillate on a distance from the valve seat without causing noise.
• Figure 1 shows a complete check valve in partial cross-section
• Figure 2 shows the lower part of the check valve in cross- section with an alternative check valve seat
• Figure 3 shows a check valve structure, which forms part of the check valve, in partial cross-section
• F/ ' gure 4 shows the check valve structure in Figure 3 seen in the view IV-IV,
• FIG 5 shows the valve seat structure in Figure 2 seen from above
• Figure 6 shows the valve seat structure in Figure 5 in the cross-section VI-VI
• Figure 7 shows the valve head
• Figure 1 shows a complete check valve arranged in a coupling nipple 1 which is intended to be coupled to a fuel pump (not shown) by means of the coupling part 3. Also connected to the nipple 1 , by means of threading onto the coupling part 2, is a fuel pipe (not shown) for a combustion engine.
• the pump is to suck fuel from a fuel tank and pressurise the pipes of the fuel system with the fuel.
• the coupling nipple includes an integrated check valve 4. This has the purpose of retaining the fuel in the fuel pipes so that the engine can be restarted immediately after the engine/pump has been switched off and that the formation of air bubbles in the pipes of the fuel system is prevented.
• Injection systems for Otto engines are preferably adapted for injection overpressure of 2.5-3.0 bar, and, if a check valve with low pressure drop is used, a weaker and cheaper pump can be used. If spherical or ball-shaped valve heads are used in the check valve, a check valve with low pressure drop is obtained, but which instead in these circumstances displays great instability in the developed flow. As, moreover, the flow is subjected to fluctuations on the one hand from the pump element of the fuel pump and on the other hand from sequential opening of the injection nozzles, the instability of the valve head is further influenced.
• the fuel pump can be a gear pump which is driven by an electric motor.
• the housing 16 of the coupling nipple, and thus of the check valve, is preferably manufactured in one single piece, for fuel systems expediently of POM plastic.
• a spring-loaded 6 check valve 4 can simply be mounted through the inlet before an insert 8, which forms the valve seat towards the inlet, is fastened.
• the valve seat structure 8 can preferably also be manufactured from POM plastic.
• the valve head 25 itself consists of a rubber valve head 25 which, via a distance element 5, is acted upon by a coil spring 6 towards a valve seat 1 1 formed on the valve seat structure 8 and counter to the direction of flow F. Consequently, the fuel can be pumped into the inlet 9 and, counter to the action of the check valve 4, reach the outlet 10 and, in the event of reversed flow, block the check valve 4 against the valve seat 1 1.
• the distance element 5 which is shown in Figures 3 and 4, is designed in its lower part with a mounting recess 23 adapted to the valve head 25.
• the valve head 25 ( Figure 7), which is manufactured from a fuel-resistant rubber material, is formed with a coupling part 27 which, by means of a press fit, is pushed firmly into the mounting recess 23.
• the recess 23 can be designed with gripping flanges 24 which project radially into the recess and grip into the coupling part 27 of the rubber valve head.
• the upper part of the distance element 5 is designed, on its cross-shaped structure, with a shoulder 21 for centring and control of the coil spring 6. In order to prevent bottoming of the spring in the event of compression, the upper part of the distance element is extended so that a stop shoulder 22 is formed.
• the check valve 4 is designed with a washer or radially projecting flange 7 between the valve head 25 itself and the distance element 5.
• a part of the flange 7, projecting radially in relation to the valve head, contributes then with an increase in the area facing the flow of over 100 per cent.
• the throughf low channel is formed with a first boring 13, situated downstream of the valve seat, at the height of the flange 7 in a closed position, which is adapted in such a manner that its diameter exceeds the flange diameter by a few per cent
• a second throttling 12 is formed in addition to the throttling between the valve head 25 itself and the valve seat 11.
• This throttling 12 has a constant throughflow area in a first part of the opening stroke of the check valve 4, followed by a gradually increasing throughflow zone 14 during a second part of the stroke.
• the gradually increasing throughflow zone 14 increases the throughflow area so that, in a third and final part of the stroke, a throughflow area corresponding to or exceeding the inlet area of the inlet 9 of the check valve 4 is obtained.
• the gradually increasing throughflow zone 14 can either be terminated in a rear edge, in the direction of flow, on the valve seat structure 8, shown in Figure 1, or merge into a constant throughflow zone 15 in the valve seat structure 8, shown in Figure 2.
• valve head diameter 5 millimetres flange diameter: 7.2 millimetres inlet diameter: 4 millimetres first boring diameter: 7.4 millimetres gradual increase to diameter: 8.8 millimetres.
• a check valve with a flange diameter of only 7.0 millimetres and other dimensions as above immediately makes the striking noises typical for check valves when the valve head bounces against the seat.
• An increase of the flange diameter to 7.1 millimetres means that the noise begins to decrease while a flange diameter of the preferred 7.2 millimetres means that the check valve becomes quiet without the valve head bouncing against the seat. This shows that the constant throttling formed between the flange and the first boring during the first part of the stroke is of great importance for obtaining a quiet check valve for pulsating flow.
• the area reduction in the throttling 12 relative to the inlet should preferably fall below 25 per cent and/ortrre gap width should be less than 0.15 millimetres.
• the area increase as a result of the flange 7 should at the same time itself be of significant dinlension, that is to say of the order of magnitude of 100 per cent and expediently within the range 70-150 per cent.
• the first boring 13 interacts with the flange 7 for 20 per cent of the stroke length or effective working stroke of the check valve.
• this interaction will take place over a part of the stroke length which is inversely proportional to the nominal developed flowthrough the check valve and proportional to the width of the gap. However, this interaction should take place over at least 10 per cent of the working stroke of the valve head.
• valve head, flange and valve seat means that, when the flow starts to be developed, the valve head 25 is forced to lift from the valve seat 1 1 to a position in which the flange lies within the gradually increasing throughflow zone 14.
• the flange of the valve head comes to find a position of equilibrium, in which the resulting force from the pressure drop over the check valve 4 corresponds to the force from the spring 6. Thte position of equilibrium can arise within the gradually increasing throughflow area 14orduring the last part of the stroke in the boring 15.
• the spring will of course be adapted for the pressure drop which is obtained with the intended flow developed for this so that the desired position of equilibrium is obtained.
• a spherical valve head which seals against a cone-shaped seat, is made use of with the advantages which these valves have with regard to pressure drop, response and sealing capability.
• effective damping is obtained of the movement of the valve head against the valve seat and, during developed pulsating flow, the valve head lies at an adequate distance from the valve seat, so that an oscillation of the valve head caused by the flow pulsation does not lead to noise.
• valve head 25 and flange 7 which form the subject of the invention.
• a valve head is obtained which, in interaction with the first boring 13 of the channel wall, forms a throttling channel 12 which effectively prevents strikethrough.
• the gradual throughflow zone 14 can, instead of a linearly increasing diameter of the channel wall, consist of recesses, running in the direction of flow and of a size which increases in the direction of flow, in a channel wall which otherwise has the same diameter as the first boring 13.
• These recesses are then expediently distributed symmetrically in the direction of the circumference overthe channel wall so that the valve head does not come into unbalance in the transverse direction.
• the recesses are, however, notto begin until after the first part of the check valve stroke.
• the check valve itself can also be given another composition than the embodiment demonstrated according to the subject of the invention.
• the projection forming the flange 7 on the distance element 5 can of course consist of a loose washer which during assembly is clamped firmly between distance element and valve head.
• the coil spring 6 acting on the check valve can also be placed alternatively between a non-movable distance element 5 which bears permanently against the inner wall of the coupling nipple and an axialiy movable composite valve head and washer.
• the complete check valve, apart from spring 6 and valve head 25, is preferably manufactured from POM plastic.
• the distance element is then premounted expediently with valve head and spring, after which this can be inserted as a unit into the inlet 9.
• Mounting is concluded by the valve seat structure 8 being threaded into the inlet and preferably welded together with the valve housing 16 by means of ultrasonic welding.
• the valve structure 8 is designed with a ridge 17 which is formed in the contact surface and is plastically deformed against the corresponding contact surface of the valve housing during welding.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Fuel-Injection Apparatus (AREA)
• Check Valves (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20378622

Family Applications (1)

Country Status (5)

Cited By (5)

Families Citing this family (32)

Citations (2)

Family Cites Families (9)

• 1990
  • 1990-02-19 SE SE9000602A patent/SE465533B/sv not_active IP Right Cessation
• 1991
  • 1991-02-19 EP EP91906535A patent/EP0516759B1/en not_active Expired - Lifetime
  • 1991-02-19 DE DE69112386T patent/DE69112386T2/de not_active Expired - Lifetime
  • 1991-02-19 WO PCT/SE1991/000123 patent/WO1991012450A1/en active IP Right Grant
  • 1991-02-19 US US07/934,468 patent/US5251664A/en not_active Expired - Lifetime

Patent Citations (2)

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