EP0265591B1 - Pumpe mit oszillierender Bewegung - Google Patents

Pumpe mit oszillierender Bewegung Download PDF

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Publication number
EP0265591B1
EP0265591B1 EP19870107692 EP87107692A EP0265591B1 EP 0265591 B1 EP0265591 B1 EP 0265591B1 EP 19870107692 EP19870107692 EP 19870107692 EP 87107692 A EP87107692 A EP 87107692A EP 0265591 B1 EP0265591 B1 EP 0265591B1
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EP
European Patent Office
Prior art keywords
valve
cam
plunger
delivery
suction
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Application number
EP19870107692
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English (en)
French (fr)
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EP0265591A3 (en
EP0265591A2 (de
Inventor
Hiroichi C/O Fuji Techno Kogyo K.K. Yoshimura
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Fuji Techno Industries Corp
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Fuji Techno Industries Corp
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Priority claimed from JP61255194A external-priority patent/JPH0754115B2/ja
Application filed by Fuji Techno Industries Corp filed Critical Fuji Techno Industries Corp
Publication of EP0265591A2 publication Critical patent/EP0265591A2/de
Publication of EP0265591A3 publication Critical patent/EP0265591A3/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B11/00—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation
    • F04B11/005—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation using two or more pumping pistons
    • F04B11/0058—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation using two or more pumping pistons with piston speed control
    • F04B11/0066—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation using two or more pumping pistons with piston speed control with special shape of the actuating element
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B9/00—Piston machines or pumps characterised by the driving or driven means to or from their working members
    • F04B9/02—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being mechanical
    • F04B9/04—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being mechanical the means being cams, eccentrics or pin-and-slot mechanisms
    • F04B9/042—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being mechanical the means being cams, eccentrics or pin-and-slot mechanisms the means being cams

Definitions

  • This invention related to a cam mechanism for driving reciprocating machines and to a constant volume pulsation-free reciprocating pump utilizing said cam mechanism.
  • Reciprocating pumps perform pumping action consisting in the suction and delivery of liquid by the reciprocating motion of a plunger, piston or the like (hereinafter referred to collectively as a plunger) in a cylinder.
  • the plunger pump as compared with other, withstands very high pressure and is superior in volumetric efficiency, so that it has been widely used in various fields.
  • the delivery action of reciprocating pumps is intermittent and the delivery rate varies to a great extent, causing the so-called pulsation. If the delivery rate is not constant at any moment, as described above, various inconveniences arise. Particularly, it cannot be put to use in process plants or other facilities which require a constant volume of liquid to be fed at all times.
  • the reciprocating pump comprises a liquid pressing chamber, a cylinder, and a plunger axially slidably installed in the cylinder to allow its one end to come in and out of the pressing chamber.
  • the pressing chamber communicates on one hand with a liquid suction port via a suction valve allowing the passage of only liquid flowing into the pressing chamber and on the other hand with a delivery port via a delivery valve allowing the passage of only liquid flowing out of the pressing chamber.
  • ball valves and poppet valves have been used as such suction valves and delivery valves. This type of valve performs an opening and closing action, that is, it is opened by liquid pressure and closed by gravitation ; thus, it is a so-called check valve allowing the passage of liquid only in one direction.
  • materials for the valve body suitable for the handling of corrosive liquid include stainless steel, ceramics, titanium, and Hastelloy.
  • Stainless steel cannot be said to universally corrosion resistant, while ceramics, titanium, and Hastelloy are too light in weight to rely on gravitation for the closing of the valve.
  • Even if a spring is to be built in it would be very difficult to obtain a spring designed to meet both requirements for corrosion resistance and spring constant.
  • the valve opening and closing action could be slow or, at time, the valve could not move at all owing to the viscosity of the liquid.
  • a spring In the case of driving by using a cam mechanism, a spring is generally used for the returning of the plunger.
  • a spring As a characteristic of a spring, there is a difference in pressure between the time the spring is expanded and the time it is contracted ; thus, to match with all operating conditions it is inevitable to use a considerably strong pressure, leading to the consumption of unnecessary energy and, moreover, durability has to be taken into account.
  • An object of this invention is to provide a reciprocating pump which is free from pulsation in the delivery rate and capable of feeding liquid always at a constant rate.
  • This invention is also intended to provide a cam mechanism which can be used in such a reciprocating machine as a reciprocating pump.
  • Another object of this invention is to provide a valve driving device for reciprocating pumps which is capable of opening and closing a valve at required times accurately corresponding to the stroke of the plunger and which eliminates the aforesaid disadvantages of the prior art.
  • a cam mechanism according to the State of the Art, as disclosed in EP-A-0172421 comprises three plate cams fixed on a common shaft so that they are spaced 120° apartfrom each other.
  • Each plate cam has a contour such that its displacement diagram has an ascending region in which displacement increases as the angle of rotation increases and a descending region in which displacement decreases as the angle of rotation increases.
  • At least either the ascending region or the descending region includes an accelerating section in which displacement acceleratingly changes, a uniform velocity section in which displacement linearly changes, and a decelerating section in which displacement deceleratingly changes.
  • the sum of the displacement per unit angle of rotation in the accelerating section and the displacement per corresponding unit angle of rotation in the decelerating section is equal to the displacement per unit angle of rotation in the uniform velocity section.
  • a reciprocating pump utilizing such a cam mechanism comprises three plunger pumps whose delivery ports are connected to a common delivery pipe, and the cam mechanism interposed between a driving device and the plunger pumps.
  • Each plunger pump comprises liquid suction and delivery ports, a cylinder having a pressing chamber communicating with said two ports, a plunger axially slidably installed in the cylinder to allow its one end to come in and out of the pressing chamber, and a cam follower rotatably supported on the other end of the plunger.
  • the three cam followers respectively abut against the three plate cams of the cam mechanism.
  • the cam mechanism is arranged as described above.
  • at least either the ascending region or the descending region corresponding to the delivery stroke of the plunger includes an accelerating section in which displacement acceleratingly changes, a uniform velocity section in which displacement linearly changes, and a decelerating section in which displacement deceleratingly changes.
  • the sum of the displacement per unit angle of rotation in the accelerating section and the displacement per corresponding unit angle of rotation in the decelerating section is equal to the displacement per unit angle of rotation in the uniform velocity section.
  • the displacement per unit angle of rotation is constant irrespective of angle of rotation and hence of time, so far as at least either the ascending region or the descending region which corresponds thereto is concerned. Therefore, in a reciprocating pump utilizing such cam mechanism, the combined delivery rate by the three plungers is constant irrespective of time.
  • cam mechanism in a driving system for three reciprocating machines in this manner, during at least the advancing stroke or the retracting stroke of the reciprocating machine, the combined stroke. per unit angle of rotation of the cam shaft or per unit time can be maintained constant at all times.
  • a driving device for such reciprocating pumps comprises a spring urging a suction valve in the valve closing direction, a cam operatively associated with the driving device of the plunger to open the suction valve against the pressing force of said spring during the time interval from the initial end of the terminal end of suction stroke of the plunger, and a cam operatively associated with the driving device of the plunger to cancel the pressing force of the spring acting on the delivery valve during the time interval from a little short of the delivery stroke of the plunger to the terminal end of the delivery stroke.
  • the suction valve driving cam forcibly opens the suction valve against the pressing force of the spring, while the delivery valve driving cam effects forced closing of the delivery valve by the spring.
  • the suction valve driving cam forces the suction valve to be closed by the pressing force of the spring.
  • the delivery valve driving device cancels the pressing force of the spring acting on the delivery valve at the terminal end of the suction stroke, that is, a little short of the initial end of the delivery stroke.
  • the respective timings of the opening and closing of the suction and delivery valves can be caused to coincide with desired points of time on the plunger stroke.
  • Such effect is particularly useful for a reciprocating pump which feeds viscous liquid.
  • this result is achieved by improvements in the shape of the plunger driving cam as defined in claim 1.
  • a plunger restoring device for the reciprocating pumps discussed here comprises fluid chambers for receiving fluid of predetermined pressure respectively installed at a plurality of plunger pumps, all the fluid chambers communicating with each other.
  • Fluid being forced out of the fluid chambers of some plunger pumps included in those of the plurality of plunger pumps which are on their delivery stroke flows distributively into the respective fluid chambers of the remaining plunger pumps which are on their suction stroke, thereby returning the corresponding plungers.
  • the fluid being forced out of the corresponding chamber flows distributively into the chambers corresponding to other plungers which are retracting, thereby returning the corresponding plungers.
  • the total amount of fluid in all chambers and in the pipeline allowing them to communicate with each other is substantially constant at all times, enabling the return movement of the plunger to be effected smoothly.
  • the fluid pressure the lowest pressure required to return the plunger is sufficient and since it is constant at all times, there is no energy loss involved as there is in the case of using a spring.
  • the surface pressure which acts on the cam follower during the return movement of the plunger is constant at all times, so that localized wear of the cam can be prevented.
  • the present mechanism is rational.
  • the ascending and descending regions are axially symmetrical.
  • the displacement curves a1-a3 are of the same shape, only differing in phase by 120° from each other, the manner of intersection being of two kinds alternating every 60° (indicated by I and II in the figure).
  • each of the accelerating and decelerating sections has minimal influence on pulsation, and may be fashioned in any manner, provided no steep-angled turn take place. This is indicated in Figs. 15A and 15B by the phantom lines. Specifically, in Fig. 15B, the constant accelerating portion, as indicated by the straight phantom line, may be removed and instead, the curve may be drawn so that the ascending portion may merge into the descending portion.
  • the average delivery rate during the advance and return strokes is as indicated by a dash dot line.
  • a dash dot line In the case of the so-called single acting triple type having three plungers spaced a crank angle of 120° apart from each other, the situation is as shown in Fig. 3.
  • a reciprocating pump comprises three plunger pumps driven by a cam mechanism 10.
  • the cam mechanism 10 includes a cam shaft 13 rotatably supported in bearings 12 housed in a cam box 11, and three axially spaced plate cams 14 fixed on the cam shaft so that the angle of attachment differs successively by 120°.
  • Each plunger pump comprises a liquid pressing chamber 21, a cylinder 22, and a plunger23 axially slidably installed in the cylinder 22 to allow its one end to come in and out of the pressing chamber 21.
  • the pressing chamber 21 is formed in a head block 24 positioned at the end of the cylinder 22 and communicates on the one hand with a liquid suction port 26 through a suction valve 25 which allows passage of only fluid flowing into the pressing chamber 21 and on the other hand with a delivery port 28 through a delivery valve 27 which allows passage of only fluid flowing out of the pressing chamber 21.
  • the delivery ports 28 lead to a common conduit or delivery pipe (not shown).
  • the cylinder 22 is attached to a cylinder case 30 fixed to the cam box 11. That is, the cylinder 22 and head block 24 are clamped by bolts 32 between the cylinder case 30 and a locking plate 31.
  • the other end of the plunger 23 is coaxially integrally connected to a guide piston 33 axially slidably extending in the cylinder case 30. Rotatably supported at the end of the guide piston 33 is a cam follower 34.
  • an annular chamber 39 is defined around the plunger 23 by the end surface 37 of the cylinder 22 and the end surface 38 of the guide piston 33.
  • the chamber 39 communicates with a hole 40 formed in the cylinder case 30.
  • the hole 40 is connected through a pipeline to a pressure fluid source such as an accumulator or a refill making use of a spring piston.
  • a pressure fluid source such as an accumulator or a refill making use of a spring piston.
  • Such returning force may be imparted by a spring, as well-known in the art.
  • the same function can be attained also by an arrangement wherein all the chambers communicate with each other through a pipeline, with one end of the pipeline being connected to said pressure fluid source and the other end being closed.
  • an oil pump as the pressure fluid source and install a relief valve at the other end of the pipeline.
  • the reciprocating pump of the aforesaid arrangement operates as follows.
  • Fig. 5 corresponds to a state in which the angle of rotation in the displacement diagram of Fig. 1 is zero.
  • a first plunger as indicated by the displacement curve a1
  • Second and third plungers will perform the aforesaid movement as they are delayed successively by 120°.
  • the first 60° duration I With attention paid to the first 60° duration I, it will be seen that when the first plunger is on the accelerating forward stroke, the second plunger is on the uniform velocity stroke as indicated by the displacement curve a2 and the third plunger, as indicated by the displacement curve a3, is on the decelerating return stroke. In the next 60° duration 11, the first plunger enters the uniform velocity forward stroke, while the second plunger is on the decelerating return stroke and the third plunger on the accelerating return stroke. Thus, when only the forward (delivery) stroke is considered, it is seen that the uniform velocity stroke of one plunger and the combined return stroke of the remaining two plungers alternate every 60°.
  • each plate cam is such that the sum of displacement A h2 per unit angle of rotation in the accelerating section of the displacement diagram and displacement A h2 per corresponding unit angle of rotation in the decelerating section is equal to displacement A H per unit angle of rotation in the uniform velocity section.
  • a Q + ⁇ q1 + A q2 holds, and the delivery rate of the reciprocating pump is always constant.
  • the fluid for returning the plungers since the fluid for returning the plungers only moves to and fro between the three chambers 39 with its total amount remaining unchanged, nor increased or decreased theoretically, the opposite ends of the pipeline 15 may be closed.
  • a pump of minimum capacity may be provided to compensate for such loss of fluid.
  • the pressurized fluid source in addition to a pump it is possible to use an accumulator or a refill utilizing a spring piston.
  • the three chambers 39 corresponding to the three plungers 23 communicate with each other through the pipeline 15 connected to holes 40.
  • One end of the pipeline 15 is connected to a pressure source 16 such as an oil pump or accumulator, and the other end of the pipeline 15 communicates with a relief valve 17 (not necessary where the pressure source is an accumulator).
  • a pressure source 16 such as an oil pump or accumulator
  • the other end of the pipeline 15 communicates with a relief valve 17 (not necessary where the pressure source is an accumulator).
  • the chambers 39 are always full of pressurized fluid.
  • This pressurized fluid acts on the end surface 38 of the guide piston 33, producing a returning force which tends to move the guide piston 33 and plunger 23 to the right as viewed in the figure.
  • the area of the end surface 38 and the pressure of the pressurized fluid may be so determined as to impart the irreducible minimum of returning force for return stroke to the plunger 23.
  • the suction valve 25 positioned between the liquid suction port 26 and the pressing chamber 21 comprises a valve head 42 formed conically on one end of a valve stem 41, and an annular valve seat43 cooperating therewith.
  • the valve stem 41 extends through a hole in the valve seat 43 and has a threaded portion 44 on the other end thereof.
  • the threaded portion 44 has threadedly mounted thereon a spring seat 45 and a cam abutting nut 46.
  • the valve stem 41 is urged by a spring 48 disposed between the spring seat 45 and a locking joint 47 to cause the valve head 42 to abut against the valve seat 43.
  • the locking joint 47 is threadedly inserted in the head block 24 and provides a communication passage 49 between the suction valve 25 and the suction port 26.
  • the valve seat 43 has a plurality of guides 50 for radially guiding the valve head 42.
  • a lever 52 pivotally connected at one end to the locking plate 31 by a pin 51 is formed at the other end with a pawl 54 cooperating with a suction valve driving cam 53 and at its intermediate portion with a projection 55 cooperating with a cam abutting nut 46 (Fig. 8).
  • Asupport shaft 56 carrying the cam 53 is rotatably supported between a pair of brackets 57 and is operatively connected to the cam shaft 13 of the cam mechanism by a transmission device (not shown) comprising sprockets and a chain. That is, when the cam shaft 13 is rotated one revolution, the support shaft 56 is also rotated one revolution.
  • the contour of the suction valve driving cam 53 comprises a large diameter portion 58 extending along substantially half the circumference of the cam 53 corresponding to the suction stroke of the plunger 23 and a small diameter portion 59 extending along the remaining substantially half the circumference of the cam 53 corresponding to the delivery stroke of the plunger 23.
  • the large diameter portion 58 includes a slope portion 60 smoothly continuous with the small diameter portion 59 and corresponding to the terminal end of the suction stroke, i.e. the initial end of the delivery stroke. Further, in the portion corresponding to the terminal end of the delivery stroke, the two portions 58 and 59 are discontinuous, forming a step 61.
  • the delivery valve 27 positioned between the pressing chamber21 and the liquid delivery port 28, as shown in Fig. 9, comprises a conical valve head 62 and an annular valve seat 63 cooperating therewith.
  • the extension 64 of the valve head 62 is provided with a plurality of radially extending guide ribs 65.
  • the guide ribs 65 are adapted to come in slide contact with the hole of the valve seat 63 to radially guide the valve head 62.
  • Extending through a locking joint 67 threadedly inserted in the head block 24 to provide a communication passage 66 between the delivery valve 27 and the delivery port 28 is a valve stem 68 which is coaxial with the valve head 62 and axially slidable.
  • the valve stem 68 has a spring seat 69 threadedly attached to one end thereof.
  • a hanger plate 70 attached to the extension 31' of the locking plate 31 has an adjusting screw 71 threadedly inserted therein.
  • a spring 72 interposed between the adjusting screw 71 and the spring seat 69 urges the valve stem 68 downward as viewed in the figure.
  • this spring 72 causes the valve stem 68 to press the valve head 62 against the valve seat 63.
  • a lever 74 supported at one end in the extension 31' by a pin 73 is formed at the other end thereof with a pawl 76 cooperating with a delivery valve driving cam 75 and at its intermediate portion with a projection 77 abutting against the spring seat 69 (Fig. 11).
  • a support shaft 79 carrying a cam 75 thereon is rotatably supported between a pair of brackets 78 and is operatively associated with the cam shaft 13 of the cam mechanism by a transmission device (not shown) comprising sprockets and a chain. That is, when the cam shaft 13 is rotated one revolution, the support shaft 78 is also rotated one revolution.
  • the contour of the delivery valve driving cam 75 comprises a large diameter portion 80 extending along substantially half the circumference of the cam 75 corresponding to the delivery stroke of the plunger 23, and a small diameter portion 81 extending along the remaining substantially half the circumference of the cam 75 corresponding to the suction stroke of the plunger 23.
  • the large diameter portion 80 is greater than the small diameter portion 81 by an angle a.
  • the suitable range of a is determined by the rpm of the cam 75 and the delivery pressure of the pump.
  • the initial portion 82 of the large diameter portion 80 is smoothly continuous with the small diameter portion 81. Further, in the portion corresponding to the terminal end of the delivery stroke, i.e. the initial end of the suction stroke, the two portions 80 and 81 are discontinuous, forming a step 83.
  • Figs. 12 and 13 illustrate a mechanism for finely adjusting the timing of the opening and closing of each valve.
  • This finely adjusting mechanism is provided separately for each of this suction and delivery valve and is used to make independent fine adjustments of the timing of the opening and closing of each valve. Since these mechanisms are of the same arrangement, the one for the suction valve 25 will be taken up for description.
  • Fig. 12 shows the end of the support shaft 56 (Fig. 6) having the suction valve driving cam 53 attached thereto.
  • a sprocket 85 operatively connected to a sprocket 84 on the cam shaft 13 of the cam mechanism by a chain is loosely mounted on the support shaft 56.
  • the sprocket 85 has an adjuster plate 86 integral therewith, said adjuster plate 86 being adapted to be clamped by bolts 88 to a plate 87 keyed to the support shaft 56. Holes 89 in the plate 87 through which the bolts 88 extend are circumferentially elongated.
  • the adjuster plate 86 has a notch 91 to clear a pin fixed to the plate 87, and a pair of opposed adjusting screws 92 are threadedly inserted on both circumferential sides of the notch 91 with the pin 90 interposed therebetween.
  • the angular position of the adjuster plate 86 with respect to the plate 87 can be changed by loosening the bolts 88 and turning the adjusting screws 92 to change their axial positions.
  • this is the operation of relatively changing the angle of rotation of the support shaft 56 with respect to the cam shaft 13, or the operation of changing the timing of the opening and closing of the suction valve 25 with respect to the stroke of the plunger 23. That is, this makes it possible to simultaneously adjust the timing of the opening and closing of three cams (in the case of a triple pump).
  • the time of the opening and closing of the delivery valve 27 with respect to the stroke of the plunger 23 can be changed by a finely adjusting mechanism of the same arrangement.
  • the outer peripheral surfaces 93 of the adjuster plate 86 is formed with a notch and if the outer peripheral surface 94 of the plate 87 is correspondingly formed with graduation of predetermined spacing, the finely adjusting operation can be facilitated.
  • displacement curves a, m b and c in Fig. 14 refer to the plunger driving cam 14, the suction valve driving cam 53 and the deliveryvalve driving cam 75, respectively.
  • the delivery stroke which continues from this state until the cam shaft 13 is rotated through 180° will be considered.
  • the suction valve driving cam 53 produces no displacement during this interval of 180°.
  • the pawl 53 of the lever 52 continues to engage the small diameter portion 59 of the cam 53, giving no displacement to the valve stem 41. Therefore, the suction valve 25 remains closed.
  • the delivery valve driving cam 75 maintains displacement hc during this interval of 180°.
  • the pawl 76 of the lever 74 continues to engage the large diameter portion 80 of the cam 75. Therefore, the delivery valve 27 remains released from the pressing force of the spring 72.
  • the pressure in the pressing chamber 21 rises with the movement of the plunger 23 and as soon as the pressures on opposite sides of the valve head 62 are balanced, the liquid pushes the valve head 62 open and flows from the pressing chamber 21 to the delivery port 28.
  • the resistance at this time is only the slight weight of the valve body 62.
  • the step portion 83 of the delivery valve When the terminal end of the delivery stroke is reached, the step portion 83 of the delivery valve is reached, the step portion 83 of the delivery valve driving cam 75 disengages the pawl 76 of the lever 74 from the large diameter portion 80, whereas the pawl falls down to the small diameter portion 81. Thereby, the lever 74 descends and the valve stem 68 is moved downward as viewed in Fig. 9 by the action of the spring 72 to press the valve head 62 against the valve seat 63. Thus, the delivery valve 27 is firmly closed in an instant. Concurrently, the pawl 54 of the lever 52 is disengaged from the small diameter portion 59 of the suction valve driving cam 53 and instead starts to engage the slope portion 60. This is the start of the suction stroke ranging over the next 180°.
  • the suction valve driving cam 53 causes the lever 52 to gradually raise the valve stem 41, moving the valve head 42 away from the valve seat 43 against the pressing force of the spring 48.
  • the suction valve 25 is opened, allowing the liquid to flow from the suction port 26 into the pressing chamber 21.
  • the cam 59 maintains the pawl 54 of the lever 52 at displacement hb during the suction stroke, keeping the suction valve 25 open.
  • the delivery valve driving cam 75 raises the lever 74 at a position a little (the amount of said a, expressed in terms of angle of rotation) short of the terminal end of the delivery stroke. Since the lever 74 is contacted at its projection 77 with the spring seat 69, the valve stem 68 is moved upward as viewed in the figure against the pressing force of the spring 72, so that the pressing force of the spring 72 acting on the valve head 62 is removed. At this time, downstream of the valve head 62, i.e. on the delivery port 28 side, the liquid delivered by the previous delivery stroke remains at a predetermined pressure and the liquid which is present upstream of the valve head 62, i.e.
  • the valve head 62 in the pressing chamber 21 is at the negative pressure produced by the suction stroke ; thus, the valve head 62 remains seated on the valve seat 63 because of the difference between the pressures across the valve head 62.
  • the pawl 54 of the lever 52 is disengaged from the large diameter portion 58 of the suction valve driving cam 53 by the step portion 61 and falls down onto the small diameter portion 59, bringing the lever 52 back to its Fig. 6 state.
  • the suction valve 25 is instantly closed by the pressing force of the spring 48.
  • the displacement curve b of the suction valve driving cam 53 remains at the displacement zero and the displacement curve c of the delivery valve driving cam 75 maintains the displacement hc.
  • the suction valve driving cam 53 maintains the displacement hc and the delivery valve driving cam 75 initially makes no displacement but at a position which is a short of the terminal end of the suction stroke it makes against the displacement hc.
  • the timing of such cam is attained in that, as described above, the cam shaft 13 of the cam mechanism for reciprocating the plunger 23 is operatively associated with the support shafts 56 and 78 for supporting the cams 53 and 75 by a transmission device comprising e.g. sprockets and a chain.
  • the springs 48 and 72 are disposed outside the valve mechanisms as described above, there is no limitation due to the spring storing space as there is when they are stored in the valve mechanism, so that it becomes easier to design a spring which is effective to ensure quick and positive closing of the valve. Further, since these springs 48 and 72 do not come in contact with liquid, even in the case of handling corrosive liquid it is only necessary to give consideration to corrosion resistance in connection with only the valve head and the valve seat so far as the valve mechanisms are concerned.
  • valve driving device a modified embodiment of the valve driving device will now be described in which the closing of the suction and discharge valves is deliberately carried out in associated with the movement of the plunger, whereas the valves are allowed to open in response to a fluid pressure acting thereon.
  • the suction valve 25 is disposed between the suction port 26 and the pressure chamber 21, and comprises a valve head 42 and a cooperating annular seat 43.
  • the head 42 has a convex partspherical surface 42a formed at one end for engagement with a corresponding concave part-spherical surface of the seat 43. Threaded on the other end of the head 42 is a cap 42b.
  • the head 42 has a recess 42c for receiving a head 41 a of a drawbar 41 which extends through a hole 42d formed in the head 42.
  • the drawbar head 41 a has a convex part-spherical surface 41 b for cooperation with a concave part-spherical surface 42e formed in the valve head 42.
  • the valve head 42 is pivotable relative to the drawbar 41.
  • the axial length of the head 41 a is shorter than that of the recess 42c in the valve head, which ensures the drawbar 41 and the valve head 42 to be movable relatively to each other by a certain distance.
  • a spring seat 45 and a cam seat 46 Threaded on the other end 44 of the drawbar extending out of the hole 42d of the valve head 42 are a spring seat 45 and a cam seat 46.
  • the drawbar 41 is so biassed that the valve head 42 and the valve seat 43 contact with each other by means of a spring 48 interposed between the spring seat 45 and the suction block 47, which in turn is connected to the head block 24 to provide a chamber 49 for interconnection of the suction valve 25 and the suction port 26.
  • the drawbar head 41 a has one or more grooves 41 c in its peripheral surface which serve to establish a pressure equilibrium between the axially opposite sides of the head 41c.
  • Suction valve driving cam 53 has a cam profile including a large diameter portion 58, an inclined portion 59 in which cam lift gradually decreases, another inclined portion 60 in which cam lift gradually increases, and a zero cam-lift portion 61 connecting the inclined portion 59, 60.
  • a discharge valve 27 which, as shown in Fig. 18, comprises a ball valve 62 and a cooperating annular seat 63.
  • a pushbar 68 extends through a delivery block 67 connected to the head block 24 to provide a chamber 66 for interconnection of the discharge valve 27 and the discharge port 28.
  • the pushbar 68 is axially slidable and coaxial with the seat 63.
  • the pushbar 68 has at one end a head 68a with a conical recess for engagement with the ball valve 62, while on the other end thereof a spring seat 69 is threaded.
  • the discharge valve driving cam 75 has a cam profile including a large diameter portion 80, an inclined portion 81 in which cam lift gradually decreases, another inclined portion 82 in which cam lift gradually increases, and a zero cam-lift portion 83 connecting the inclined portions 81, 82.
  • Figs. 5, 16 and 18 are in a state in which the suction stroke has just terminated and the discharge stroke is going to begin. In that state, the suction valve 25 is closed and also the discharge valve 27 is closed due to the pressure difference thereacross, although it is relieved from the force of the spring 72.
  • fluid pressure in the pressure chamber 21 will increase with the movement of the plunger 23 until the equilibrium is established in fluid pressures across the valve 62, whereupon a pressurized fluid will burst into flow out of the pressure chamber 21 toward the discharge port 28, thrusting the ball valve 62 up against the weight of the ball valve 62 alone, which is as small as negligible.
  • the finger 76 of the lever 74 gets out of engagement with the large diameter portion 80 of the discharge valve driving cam 75 and shifts onto the inclined portion 81, thence the lever gradually be lowered to thereby allow the pushbar 68 to be moved downwardly as viewed in Fig. 18 by the action of the spring 72, resulting in the ball valve 62 being pressed against the seat 63. In this manner the discharge valve 27 is closed with assurance at the end of the discharge stroke.
  • the suction valve driving cam 53 keeps displacement hb, and the drawbar 41 is still raised.
  • the suction valve 25 is closed due to the fluid pressure in the pressure chamber 21 acting on the valve head 42.
  • the suction valve 25, which has been closed under the action offluid pressure as described now opens as a result of a decrease in pressure of the pressure chamber 21 as the plunger 23 moves to the right as viewed in the drawings to thereby allow the entrance of fluid into the pressure chamber 21 through the suction port 26.
  • the suction valve driving cam 53 keeps the displacement hb so that the suction valve 25 remains open until about 30° prior to the end of the suction stroke.
  • the finger 54 of the lever 52 gets out of engagement with the large diameter portion 58 of the suction valve driving cam 53 and enters into engagement with the inclined portion 59, allowing the suction valve 25 to be closed under the action of the spring 48.
  • the suction valve 25 is eventually closed with assurance at the end of the suction stroke.
  • the discharge valve 27, which has been closed at the end of the discharge stroke, or the beginning of the suction stroke, remains to be closed under the action of the spring 72 during the period of about 30° from the beginning of the suction stroke, since the finger 76 of the lever 74 engages with the zero cam-lift portion 83 of the cam 75 for that period.
  • the finger 76 then enters into engagement with the inclined portion 82 to gradually raise the pushbar 68 so that the valve 62 is relieved from the force of the spring 72.
  • the suction valve 25 remains to be closed under the action of the pressure difference throughout the suction stroke, and therefore any counter flow of fluid will be inhibited.
  • valve driving device of this invention is employed in a constant volume pump adapted to prevent pulsation of the delivery rate, as described above, it will contribute to improving the volumetric constancy of the pump by ensuring the accurate timing of the opening and closing of the suction and delivery valves.
  • the embodiment described herein is intended to control the opening and closing of the suction and delivery valves by cams operatively associated with the plunger driving cams.
  • cams operatively associated with the plunger driving cams.
  • the operative association of the timing of the opening and closing of the suction and delivery valves with the movement of the plungers can be made also by the following arrangements in addition to the aforesaid embodiment:
  • the invention may be embodied in the form of the cam mechanism with more than three cam plates.
  • the reciprocating pump may likewise comprise more than three cylinder-plunger arrangements.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Reciprocating Pumps (AREA)

Claims (2)

1. Pumpe mit oszillierender Bewegung mit mindestens drei Kolbenpumpen, deren druckseitige Öffnungen (28) mit einer gemeinsamen Leitung verbunden sind, und einem Kurvengetriebe (10), welches zwischen einer Antriebsvorrichtung und den Kolbenpumpen angeordnet ist, wobei jede Kolbenpumpe mindestens eine Flüssigkeits-Ansaugöffnung (26) und mindestens ein Saugventil (25) sowie mindestens eine druckseitige Flüssigkeitsöffnung (28) und mindestens ein Druckventil (27) aufweist sowie mit einem Zylinder (22) mit einer mit den Öffnungen (26; 28) verbundenen Druckkammer (21) und einem Kolben (23), welcher im Zylinder (22) axial verschiebbar angeordnet ist, so daß dessen eines Ende in die Druckkammer hinein und aus ihr hinaus bewegbar ist, und mit einem drehbar an dem anderen Ende des Kolbens (23) gelagerten Kurvenscheibenabtaster (34) und einer Vorrichtung, welche den Kolben (23) so in eine Richtung drängt, daß der Kurvenscheibenabtaster die ganze Zeit an der Kurvenscheibe anliegt, wobei das Kurvengetriebe (10) mindestens drei, auf einer gemeinsamen Welle (13) in Intervallen von 120° zueinander angeordnete Kurvenscheiben (14) aufweist, wobei die Kurvenscheiben einen steigenden und einen fallenden Bereich aufweisen,
- wobei der steigende Bereich eine Dauer von 180° besitzt, während der die Verschiebung mit dem Drehwinkel der Kurvenscheibe (14) zunimmt und derabsteigende Bereich eine Dauer von 180° besitzt, während der die Verschiebung mit der Zunahme des Drehwinkels der Kurvenscheibe (14) abnimmt, und
- wobei die Kurvenscheibenprofile so ausgebildet sind, daß die Summe der Verschiebung pro Drehwinkel-Einheit der drei Kurvenscheiben konstant ist, dadurch gekennzeichnet, daß
- der steigende Bereich und der fallende Bereich in mindestens fünf Phasen unterteilt sind,
- wobei während der ersten Phase die Beschleunigung allmäh lich zunimmt,
- während der zweiten Phase die Beschleunigung allmählich bis null abnimmt,
- während der dritten Phase die Beschleunigung null ist,
- während der vierten Phase die Beschleunigung langsam abnimmt, und
- während der fünften Phase die Beschleunigung langsam bis null ansteigt.
2. Pumpe mit oszillierender Bewegung gemäß Anspruch 1, bei der die Ventil-Betätigungsvorrichtung die Saug- und Druckventile schließt und das Öffnen der Saug- und Druckventile durch den auf diese wirkenden Flüssigkeitsdruck ermöglicht.
EP19870107692 1986-10-27 1987-05-26 Pumpe mit oszillierender Bewegung Expired - Lifetime EP0265591B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP61255194A JPH0754115B2 (ja) 1985-12-25 1986-10-27 往復ポンプ
JP255194/86 1986-10-27

Publications (3)

Publication Number Publication Date
EP0265591A2 EP0265591A2 (de) 1988-05-04
EP0265591A3 EP0265591A3 (en) 1989-03-22
EP0265591B1 true EP0265591B1 (de) 1991-07-24

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP19870107692 Expired - Lifetime EP0265591B1 (de) 1986-10-27 1987-05-26 Pumpe mit oszillierender Bewegung

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EP (1) EP0265591B1 (de)
DE (1) DE3771646D1 (de)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2783021B1 (fr) * 1998-09-09 2000-10-13 Inst Francais Du Petrole Procede et systeme de pompage de fluide utilisant une pompe avec un debit constant a l'aspiration ou au refoulement
CN114934884A (zh) * 2022-07-06 2022-08-23 西南石油大学 一种对置式凸轮往复泵动力端

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4687426A (en) * 1984-07-31 1987-08-18 Fuji Techno Kogyo Kabushiki Kaisha Constant volume pulsation-free reciprocating pump

Also Published As

Publication number Publication date
DE3771646D1 (de) 1991-08-29
EP0265591A3 (en) 1989-03-22
EP0265591A2 (de) 1988-05-04

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