ACTUATING DEVICE FOR PIPE-CHAMBER FEEDERS OF HYDRAULIC TRANSPORT EQUIPMENTS

Abstract: An actuating device for pipe-chamber feeders of hydraulic transport equipment comprising valves or other closing appliances having a closing element that is movable reciprocally between an open and a closed position, the improvement being characterized in said closing element being associated with at least one speed control means, especially a speed reducing means acting at least at the end phase of the closing stroke of said closing element. The speed reducing effect of at least one of said speed control means may be adjustable.

Description: ACTUATING DEVICE FOR PIPE-CHAMBER FEEDERS OF HYDRAULIC TRANSPORT EQUIPMENTS Field of invention The present invention relates to an improved actuating device 5 for pipe-chamber feeders of hydraulic transporting and hoisting equip¬ ments adapted to convey solid materials such as coal or slag in the form of slurry. Such actuating devices generally contain valves and other closing appliances and the invention mainly relates to the speed-controlled actuation of closing elements of these appliances. 10 Background of the invention The function of a pipe-chamber feeder consists of the periodic al alternate filling of the chambers with slurry at low pressure, and emptying them at high pressure. While performing this function, the closing appliances, especially valves or sliding valves must be opened 15 and closed by a suitable actuating device in a certain sequence and at short time periods, most advantageously in a manner as it is de¬ scribed in the Hungarian Patent Specification No. lάO 52ό. However, the closing elements of the valves have to be moved slowly because a quick closing would cause disadvantageous pressure and velocity fluc- 20. tuations, even heavy water impacts that are called water hammer in the art concerned. Consequently, in prior art devices the change-over or switch- -over steps i.e. the closing and opening of the valves are relatively slow and they result in a disadvantageous decrease of the performance 25 of transport equipments having only two pipe chambers. In such equip¬ ments every change-over consists at least of o opening and closing steps, and during the change-over operations filling or emptying of the pipe chambers is not possible. If three or ore pipe-chambers ere used there is no such de- 30 crease of the output. However, investment and operating costs of equip meπts having three or more pipe-chambers are much too high. In addi¬ tion to this, a diminishing of the time necessary for the switch- -over steps is still desirable even if the number of pipe-chambers is more than two. 55 The fact that the change-over steps in the known prior art hydraulic transport equipments are extremely time-consuming is specially disadvantageous with large-size equipments because the speed of actuation of the closing elements of big closing appliances is very slow, and also the pressure-changes in the large pipe-chambers 1G take much time. nummary of the invention Main object of the invention is to greatly diminish the de¬ crease of output caused by the slow actuation of the valves in known hydraulic transport equipments, especially in those, having two pipe- 1 -chamber feeders, and to attain that even if largest closing elements having a closing stroke as long as 300 to όOO mm are used, practically no loss in capacity or performance should occur by the change-over operations. Simultaneously, of course, water impacts should also be avoided. 20- These and other objects are attained by the present invention that results in that the closing element of the closing appliances especially closing elements of the main valves are quickly moved, say with a speed three or four times higher than up to now. Simultane¬ ously with this, the closing appliences contain one or more means for Z5. significantly reducing the speed of said closing elements at the end phase of their closing stroke i.e. just before arriving at their closed position. It may be important that the speed reducing effect should be adjustable and if one speed reducing throttling device is used only, this is preferred to be adjustable manually. If two or more 33 simultaneously functioning throttle devices are employed, it is impor- tαnt that at least in one of them the throttling effect should be adjustable. The slowing down of the closing element can be continuous or stepped. 5 Comparison of the invention with the prior art There are well known hydraulic stroke-end brakes called cataracts in which the speed of a quickly moving piston or other part is slowed down at the end of its st-oke by a fluid caused to strea through a narrow opening. However, such hydraulic stroke-end brakes 10. have never been employed in valves of hydraulic transport equipments. Thus the basic idea of the invention consists of using such cataracts for increasing the output of such equipments. It has been found that by using the invention, a hydraulic transport equipment having two pipe-chamber feeders will have a capa- 15 city which was attained up to now by vexy expensive three-chamber equipments only. A further novel feature of the invention is that the throttling effect to be employed at the end of the closing stroke of the closing elements should be adjustable so as to be able to alter the slowing 20. effect. In fact when designing the equipment in most cases it is not possible to predict the most advantageous throttling effect and thus the speed at the end of the closing stroke should be determined expe¬ rimentally during the trial run of every equipment. A further surprising effect of the invention lies in the 2S following* The sludge or slurry is filled in the pipe-chamber by means of a pump working with low pressure. During the necessary change-over periods this filling is interrupted. Consequently, in the known prior art equipments, if the sludge is continuously pumped into the sludge 30 container, the solid particles contained tend to sedimentation during the period of change-over, and this may cause serious breakdowns. The Not to be taken into consideration for the purposes of international processing (Administrative Instructions, Section 309(c). hydraulic cylinder 4 with little resistance, so that the closing element is moved quic kly. The preliminary regulator 6B is suitable to ad just the speed of the several closing element s if present in the device relatively to each other , 5 " . Oil pressed out from cylinder 4 streams through a preliminary regulator όA which serves f 0 r exactly ad just ing the quick moveme nt speed of the piston. It is clear that the choking effect set by the preliminary regulators όA and όB is effective along the whole stroke of the piston. Oil leaving preliminary regulator όA flows through 10. further change-over t hrottle valves SA and SB which, in the position shown in the drawing, let through the oil practically without thrott¬ ling . The oil leaving the change-over throttle valves 8A and 8B re¬ t urns to the fluid tank 1 after passing again the reversing valve 3. When the closing element 5A arrives near it s closing position, 15 a buffer 7 secured t o the piston rod 9 reaches a cont rol lever of the change-over throttle valve 8A and brings this valve against posit ive spring effect in it s throttling position . Consequently t he stream of oil coming from cylinder 4 is throttled by this valve 8A so that the speed of the closing element 5A is reduced . When said buffer 7 20 continues it s movement it reaches the other change-over throttle valve 83 and it is also brought into it s throttling posit ion. As a result of this, the speed of movement of the closing element 5A become still slower . Since the resulting throttling effect is ve∑y closely adapted to the valve characteristics shown in Fig . 1 of the drawing, 25 no water impact and no disadvantageous pressure fluct uat ion will occυrre upon closing . Valves 8A and 83 can be regulated or ad justed in order to find a resulting choking effect t hat is most advantageous for the closing operation. 30 If the closing appliance is to be opened, the closing eleaeπt 5A starts its movement with a slow speed because the oil streaming now in the φposite direction must pass through valves 8A and 8B that are in their throttling position. However, when t he buffer 7 leaves the valves 8B and 8A, they are brought by means of springs in a few seconds sequence in their non-throttling positions so that the opening movement of the closing means is speeded up to it s full speed . ' From the above description it is clear t hat the device is suitable for adj usting the speed of the closing element in t he vicinity of it s closing position to a certain max imum value of velocit y at which water impacts and similar harmful effect s are surely avoided . Along the remaining part of the stroke, however, the speed ca n be set to a value equal to a ultipe of said speed . Consequently the change-over operation of the pipe-chamber feeder takes a very short time period only. Instead of the above described mechanical device also an electronic embodiment may be employed for instance in a way that the . buffer 7 on the piston rod 9 controls an electric or electronic stitch which in turn causes a change-over of a valve or of valves . It has already been proposed to move the closing element s by means of electro¬ magnet s instead of a hydraulic piston, a nd according to the invent ion, also in such embodiment s it is possible to control t he speed of move- 0 ment of the closing element in a manner that a strong electromagnet first quickly drives the closing eleme nt at t he beginning of it s clos¬ ing st roke and at the end-phase of it s closing stroke near the valve seat the speed of t his element is reduced . Descript ion of a second preferred embodiment 5 According to Fig. 3 a plunger body 13 and a piston rod 12 of a hyd¬ raulic piston 10 are arranged in a cylinder 4A with sliding fit . Two extensions 14 and 15 situated between said plunger body 13 and said piston rod 12 have a smaller diameter t ha n the inner diameters of stepped portions 16 and 17 of the hydraulic cylinder 4A respectively. 0 he stepped portions 16 and 17 are made in that βnd part of the hydra¬ ulic cylinder 4A which is turned towards the closing element to be act uated which is not shown in Fig. 3 but can be clearly seen in Fig . 2. The position of the piston 10 shown in Fig. 3 in dotted lines corresponds to its end position in which the closing element not shown in Fig . 3 /and driven by t he hydraulic piston/ is in it s fully opened position. If now t he hydraulic fluid is fed into the hydraulic cylinder 4A through inlet channel 11A, t he piston start s its closing movement wit h a very high speed, because the oil on the other side of the hydraulic piston 10 may leave through a chanel 113 practically uπthrottled. The speed of the hydraulic pist on 10 is shown by V in the diagram of Fig , 3. When the hydraulic piston 10 attains the posit ion shown in full in Fig, 3, t hrottling of the flow of oil begins, because in cour of the furt her movement of the hydraulic piston 10 the oil is compell to pass through the narrow cylindric interspace between the extention 14 and the first stepped por tion 16 of the hydraulic cylinder 4A. Streaming through this cylindrical interspace means a certain throttl of the flow and thus, the speed of the piston is reduced to a value V, as shown in the above ment ioned diagram in Fig . 3 of the drawing . ψ ~ en the hydraulic piston 10 continues its stroke of travel , also the second extension 15 comes into the area of the second steppe portion 17 and a s a result , a double t hrottling effect occurs . The speed of the hydraulic piston 10 further diminishe s to the value VΛ , so that the closing movement of t he closing eleme nt driven by the hydraulic piston 10 is accomplished by a slow speed as generally required in hydraulic t ransport equipments . Of course, for performing t he above task, chanel 11B opens into the veiy end port ion of the hydraulic cylinder 4A i .e . it joins the narrowest end section of said cylinder 4A. If the closing element connected to the piston rod 12 is to be opened the high pressure oil enters the hydraulic cylinder 4A through the chanel 11B and init ially a double t hrottling effect pre¬ vails . After a short time the oil streams under single t hrottling resistance only, and when the piston 13 arrives to the position shown in full lines in Fig. 3, it continues its movement under full pressu¬ re and with maximal speed V . The invention is not limited to the two stepped throttling embodiment as described above by way of example only. In some cases a single throttling can be sufficient or, on the contrary even more than two steps are necessary. Since the device as shown in Fig. 3 of the drawing cannot be adjusted manually to the best throttling effect, it is advantageous to combine this embodiment with at least one further adjustable throttling device.

Claims: Claims 1. An improved actuating device for pipe-chamber feeders of hydraulic transport equipments, said actuating device compris¬ ing valves or other closing appliances having a closing element 5 that is movable reciprocically between an open and a closed posi¬ tion, the improvement in said actuating device being characterized in said closing element being associated with at least one speed control means, especially a speed reducing means acting at least at the end phase of the closing stroke of said closing element. 0 2. An improved actuating device as claimed in Claim 1 wherein the speed reducing effect of at least one of said speed control means is adjustable. 3. An improved actuating device as claimed in Claim 1 or 2 in which said closing element of said closing appliance is driven by 5 a hydraulic piston that is moved in a hydraulic cylinder, characterized in said speed reducing means being provided by at least one throttling means, preferably a throttle valve that is inserted into at least one of the pipe-lines feeding or leading away, respectively, hydraulic fluid into or from said hydraulic cylinder. C 4. An improved actuating device as claimed in Claim 3 charac¬ terized in said at least one throttling means being adjustable manu¬ ally. 5. An improved actuating device as claimed in Claim 3 in which the throttling effect of said throttling means is effective substantia 5 over the whole stroke of said closing element. 6. An improved actuating device as claimed in Claim 1 - 3 characterized in said throttling means, preferably throttle valve bein inserted into the pipeline that is leading away the hydraulic fluid from said hydraulic cylinder upon actuation. 0 7. An improved actuating device as claimed in Claim 6 wherein two or more throttling means, preferably throttle valves are arranged and actuated in sequence one after the other by a suitably shaped coapoπent part that is moved together with said hydraulic piston in order to provide α variable, preferably stepped throttling effect to said hydraulic piston and thus, to said closing element of said closing appliance at both the end-phase of the closing stroke and the starting phase of the opening stroke of said closing element. 8. An improved actuating device as claimed in Claim 1 wherein said closing element cf said at least one closing appliance is driven by a hydraulic piston that is moved in a hydraulic cylinder, and wherein said speed control means, especially speed reducing means is provided by the end portions, facing said closing element, of both said hydraulic piston and said hydraulic cylinder being stepped in their inner and outer diameters respectively, whereby a variable circular interspace for the throttled flow of the hydraulic fluid is left free between the adjacent stepped surfaces of said hydraulic piston and hydraulic cylinder upon moving said closing element towards or from its closed position. 9. An improved actuating device as claimed in Claim 8 wherein the pipeline for leading away the hydraulic fluid from said hydraulic cylinder upon closing said closing element is joined to said hydraulic cylinder at its section of smallest diameter. List of reference numerals 1 fluid tank 2 pump 3 reversing valve 4 hydraulic cylinder 4A hydraulic cylinder 5 closing appliance 5A closing element όA preliminary regulator 63 preliminary regulator 7 buffer 8A change-over throttle valve SB change-over throttle valve 9 piston rod 10 hydraulic piston 11A inlet channgel 113 outlet channel 12 piston rod 13 _ plunger body 14 extension 15 extension 16 stepped portion 17 stepped portion

Inventors: AJTAI LASZLO, ILLES KAROLY, KOCSANYI LASZLO, AJTAI, LASZLO, ILLES, KAROLY, KOCSANYI, LASZLO
Applicants: HEVES MEGYEI TANACSI, KOEZPONTI BANYASZATI FEJLESZTE, HEVES MEGYEI TANACSI EPITOEIPARI VALLALAT, KOEZPONTI BANYASZATI FEJLESZTESI INTEZET
Application year: 1985
Main classification: F16K31
IPC codes: E21F13, F16K31, F16K47