GB2209042A - Hydraulic pulse generator - Google Patents

Description

4 HYDRAULIC PULSE GENERATOR This invention relates to mining, particularly

to hydraulic pulse action machines used for hydraulick- ing, and more particularly to hydraulic pulse generators The invention can find application in the mining industry and in waterworks engineering for breaking rock formations by iiigil-pressure pulsed water jets. It can also be used in power engineering for cleaning boiler installations of heat-electric generation plants.

There is known a hydraulic pulse generator (cf., SU9 Aq 768,968) comprising a hydropneumatic accumulator communicating with a supply pipeline, an oscillations generator communicating by way of a pipe with the hydropneumatic accumulator, a mechanism for controlling the movement of a hollow piston connected to an oscillations generator, and a working nozzle communicating with the oscillations generator by way of another pipe; the diameter of the pipe connecting the oscillations generator with the working nozzle being two thirds of the diameter of the pipe connecting the oscillations generator with hydropneumatic accumulator at equal pipe length.

Operation of tile hydraulic pulse generator is based on accelerating the flow of water in the pipe between the oscillations generator and hydropneumatic accumulator through a relief nozzle, accelerating the 1 water flow still further in the pipe between the oscillations generator and working nozzles and subsequent decelerating the flow before the working nozzle.

However,this apparatus is characterized by insuf- ficiently high pressure before the working nozzle attainable at a definite ratio between the lengths and diameters of the pipes, and therefore low efficiency in operation. In addition, fluctuation of the column of water in the pipe between the oscillations generator and working nozzle results in that a high pressure pulse generaed before the viorking nozzle is follo,..ed by low pressure pulses havinr-. no breaking effect on an object being hydraulicked, the power of the high- pressure water jet is reducedg and undesirably large quantities of water thrown against the object being hydraulicked takes place.

There is also known a hydraulic pulse generator (cf.y SUs A, 1,081,350) comprising a hydropneumatic accumulator mounted on a supply line and communicating 2e) by a pipe i?.,ith an oscillations generator connected by a second pipe to a flow switch which includes a working nozzle arid a relief nozZle. The oscillations generator is disposed between the pipes and comprises a piston and a relief nozzle. The flow switch comprises a housing accommodating a shut-off member in the form of two pistons connected by a rod to form inside the housing after-seat and alEterpiston cavities, one of the afterseat cavities communicating with the working nozzles 1 Z k the other after-seat cavity communicating with the relief nozzle. The work.ing. nozzle and relief nozzle have equal diameters.

Operation of this machine involves acceleration of water in the pipe between the oscillations generator and hydropneumatic accumulator through the relief nozzle of the oscillations generator, additional acceleration of the water flow in the pipe between the oscillations generator and flow switch through the relief no zzle, and subsequent deceleration of the flow before the working nozzle.

This prior art machine is characterized by low ef ficiency of hydraulicking due to low amplitude of high pressure in the pulse caused by equal diameters of the working and relief nozzles in the flow switch, and by invariable cross- section of the pipe between the oscillations generator and flow switch.

It is an object of the present invention to achieve a higher amplitude of high pressure in the pulse.

Anothe- object is to ensure a higher efficiency of bydraulicking.

The objects of the invention are attained by that in a'hydraulic pulse generator comprising a supply pipeline having mounted thereon a hydropneumatic accu- mulator communicating by way of a first pipe with an oscillations generator which communicates by way of a second pipe with a flow switch including a working ( (- -4- nozzle and a relief nozzle, according to the invention, the second pipe is made up of at least two sections of different diametersq the aiameter of each preceding section being two times the diameter of each succeeding section in order to form a flow with various phases of pressure oscillations.

Preferably, in order to form a flow with various phases of pressure oscillations. the working nozzle and relief nozzle have a ratio between their diameters 10 of 1:3.

In view of the aforedescribed, the use of the second pipe made up of at least two sections of different diameters makes it possible to accumulate a definite quantity of water in the high phase of oscillations under high pressure and ensure additional acceleration of the liquid in the low phase of oscillations as water escapes from the relief nozzle. The preference for the diameter of the relief nozzle to be three times the diameter of the working nozzle is dictated by accelera20 tion of water to the maximum possible velocity.

Other advantages of the invention will become more fully apparent from a more detailed description thereof taken in conjunction with the accompanying drawings the sole Figure of which shows a sectional view of a hydraulic pulse generator according to the invention.

A hydraulic pulse generator comprises a hydropneumatic accumulator 2 arranged at a supply pipeline k 1 and communicating by way of a first pipe 3 with an oscillations generator 4 in turn communicating by way of a second pipe 5 with a flow switch 6 having a work- ing nozzle 7 and a relief nozzle 8. The second pipe 5 5 is made up of two sections 9 and 10. the diameter of the.section 9 beinG twice as large as the diameter of the section 10. The working nozzle 7 and pressure relief nozzle 8 have a ratio between their diameters 1..3. The oscillatlions generator 4 comprises a hollow piston 11) a mechanism 12 for controlling the movement of the hollow piston 11, and a pressure relief nozzle 13. The flow si,.,.itch 6 is disposed at the end off the section 10, a housinE 14 of the flow switch 6 having seats 15 and 16 forming an interseat cavity 17 and after-seat cavities 18 and 19. The after-seat cavities 18 and 19 accommodate pistons 20 and 21, respectively, interconnected by a rod 22. After-piston cavities 23 and 24 are disposed after the pistons 21 and 20, respectively. Therewith, the after-piston cavity 25 communicates thro- .0 ugh a by-pass pipe 25 with the after-scat cavity 19, whereas the after-piston cavity 24 communicates with the supply pipeline 1.

The hydraulic pulse generator embodying the present invention operates in the following manner.

Subsequent to the admission of water from the supply pipeline 1 the hydraulic pulse generator initiates self-oscillations; each period of such self-oscillations including two phases; a low phase and a high k - phase. Tne low phase sets on arter the hollow piston 11 of tile oscillations generator 4 is moved by the mechanism 12 for controlling the movement of the hollow piston 11 toward the section 9 of the second pipe 5. This is accompanied by termination of hydraulic communication between the first pipe 3 and second pipe 5. The pipe 3 communicates with the pressure relief nozzle13 of the oscillations 6enerator 4. and the pressure in the zone of the oscillations generator 4 drops. The pipe 3 conveys a wave of low pressure from the oscillations generator 4 to the hydropneumatic accumulator 2 which is reflected therefrom by a wave of pressure close to the atmospheric. Normally, 5 - 4 low pressure waves are propagated in the low phase between the oscillations generator 4 and hydropneumatic accumulator 2 due to the action of the mechanism 1.2 for controlling the movement of the hollow piston 11. As each reflected wave comes to the oscillations generator 4, the speed of water flow in the pipe 3 and pressure in the zone of the oscillations generator grow spasmodically. When the pressure difference at the hollow piston 11 and in the mechanism 12 for controlling the movement of the hollow piston 11 is sufficient to cause its movement, the piston 11 travels toward the pipe 3. The pressure relief nozzle 1 sauts off, and the pipes 3 and 5 start to communicate hydraulically. The low phase of oscillations is therefore terminated, and the high phase Of floly oscillations in the Ape 3 starts.

( 1 With the pressure relief nozzle 13 having a low hydraulic resistance closed, the pressure in the zone of the oscillations generator 4 grows to become higher than the supply pressure. A wave of this high pressure propagates along the pipe 3 to the hydropneumatic accumulator 2 and along the section 9 of the second pipe 5 to the point of connection between the two sections 9 and 10. At equal lengths of the pipe 3 and sections 9 and 10 of the second pipe 5 the wave tra- vels along the pipe 3 to come to the hydropneumatic accumulator 2, and also moves along the second pipe 5 to reach the point of connection between the sections 9 and 10. The flow is somewhat decelerated due to the difference in the diameters of the sections 9 and 10 of the second pipe 5. The pressure tends to grow still further, and a wave of this pressure propagates from point o-LI connection between the sections 9 and 10 in two directions: along the section 9 toward the oscillations generator 4, and along the section 10 toward the flow switch 6. The speed of water flow in the section 10 is higher than that in the section 9 in view of different diameters of these sections 9 and 10, whereby a flow of different pressure oscillation phases is formed.

As the wave reflected from the hydropneumatic accumulator 2 comes to the oscillations generator 49 the hollow piston 11 is acted upon by the control mechanism 12 to move to the second pipe 5, the pressure k relief nozzle 13 opens. and hydraulic connection between the pipes 3 and 5 is terminated. This ends the high phase of pressure oscillations in the pipe 3 and the low phase to begins. The wave reflected from the point of connection between the sections 9 and 10 travels at one side to the oscillations generator 4. where it comes across a dead end (since the hydraulic connection between the pipes 3 and 5 is terminated by this time), and at the other side reaches the flow switch 6. Therewith, a wave of low pressure Is generated at the start of the section 9, which signifies that at the general flow of water along the sections 9 and 10 of the second pipe 5 no water is admitted from the pipe 3 to the flow switch 6. In the zone of the flow switch 6 the pistons 20 and 21 are caused to move with the piston rod 22 toivard the after- piston cavity 24. The piston 21 seats on the scat 15. The pressure relief nozzle 8 is closed and the working nozzle 7 opens. The pressure before the working nozzle 7 grows to the maximum. The pistons 20 and 21 with the rod 22 are caused to move due to that a wave of increased pressure reflected from thepoint of connection between the sections 9 and 10 reaches the flow switch 6, this pressure acting on the piston 20 from the interseat cavity 17 being substan- tially greater than the supply pressure in the afterpiston cavity 24. On the other hand, the pressure acting on the piston 21 at the side of the after-seat cavity 19 and after-piston cavity 23 is equal, thanks Ir 1 k to the overflow of water along the by-pass pipe 25. As a result of closing the pressure relief nozzle 8 (of low hydraulic resistance) and opening the working nozzle 7 (of high hydraulic resistance) having a diameter three times the diameter of the pressure relief nozzle 8, the pre-ssure grows to the maximum.

Thereby, a high pressure pulse flow of maximum amplitude is discharged from the working nozzle 7 toward an object to De n,-,.draulicked.

A high oscillations phase is initiated in the section 10 of the second pipe 5. A wave o1C this maximum pressure and velocity of the flow determined by this pressure and diameter of the working nozzle 7 propagates along the section 10 to the point of connection between the sections 9 and 10 to meet here a wave ef reduced pressure and zero velocity reflected from the oscillations generator 4 (dead end). Thanks to adding these waves the pressure in the joint flow tends to reduce remaining, however, somewhat higher than the sup- ply pressure, whereas the direction of the flow changes. Prom the zone of high pressure (viz., section 10) water flows to the zone of reduced pressure (viz., section 9). Therefore, a new wave of negative flow speed and of a pressure somewhat exceeding the supply pressure propagates from the point of connection between the sections 9 and 10. At the same time, the first wave of reduced pressure is reflected from the hydropneumatic accumulator 2. When this wave reaches the oscillations - lO - generator 4 and the second wave of reduced pressure starts to travel alon- tile pipe 3 toward the hydropneumatic accumulator 29 a wave of negative velocity propagates along the section 9 to the oscillations generator 4 (dead end) and along the section 10 to the flow switch 6 from the point of connection between the sections 9 and 10. In the first case this results in a certain pressure growth due to collision of the flow with the dead end), whereby a wave of the same pressure and zero velocity will travel to the point of connection between the sections 9 and 10, whereas in the second case a pressure drop to the atmospheric will ensure in the zone of the flow switch 6 due to the negative velocity of flow in the incoming wave. This in turn results in that the pistons 20 and 21 with the rod 22 travel toward the after-piston cavity 23 under the action of the supply pressure in the cavity 24. A wave of atmospheric pressure and negligeably positive or negative velocity (depending on the pa-ameters of the sections 9 and 10) will propagate along the section 9, whereafter the high phase of pressure oscillations in the section 10 ends and low phase begins. It is to be noted that by this time in the pipe 3 the first wave of low pressure executes a first complete run in the low phase, that is the oscillations phases in the two pipes are shifted in time equal to twice the travel run of a shock wave along the Pipe 3.

As the second wave travelling in the low phase p 1 of oscillations along the pipe 3 reaches the hydropneumatic accumulator 21 a second wave of zero velocity moves along the section 9 to the point of connection between the sections 9 and 10. Again, a first wave of atmospheric pressure in the low phase of flow oscillations will move along the section 10 from the flow switch. As a result, at the point of connection between the sections 9 and 10 the flow again acquires a positive velocity due to tile arrival of a wave of pressure ex- ceeding the atmospheric pressure from the section 9 and of a wave ol' atmospheric pressure from the section 10 to be followed by overflow from the section 9 to the section 10, the pressure remaining somewhat higher than the supply pressure. A wave having such parameters will again propagate from the point of connection between the sections 9 and 10 to the oscillations generator 4 and to the flow switch 6. As the wave reaches the flow switch 61 pressure before the relief nozzle 8 grows to above the atmospheric to result in an increase in the speed of the flow at the end of the section 10. At the same time, shock waves travel from both sides toward the oscillations generator 4: one wave is reflected from the hydropneumatic accumulator 2 (second reflected wave in the low phase) to propagate along the pipe 3, and the other travels along the section 9 from the point of counection between the sections 9 and 10. If the mechanism 12 for controlling the movement of the hollow piston 11 is adjusted h 1 for operating conditions envisaging only two waves in the pipe 3 in the low phasel then the hollow piston 11 of the oscillations generator 4 is caused to move to- ward the pipe 3. The pressure relief nozzle 13 closes for the pressure in the pipe 3 to again grow to one that is higher than the supply pressure, whereby the high phase begins. The pressure in the zone of the oscillations generator 4 grows to one that is considerably higher than the supply pressure. A new wave of high pressure will propagate from the oscillations generator 4 along the pipes 3 and 5. As this wave travels along the pipe 3 to reach the kydropneumatic accumulator 2 and be reflected therefrom, the wave (with a pressure above the atmospheric, and a positive velocity flow.) in the section 9 reaches the point of connection between the sections 9 and 10 where it meets with the wave previously reflected from the pressure relief nozzle 8 travelling along the section 10. In consequence, a new wave will propagate from the point of con- nection between the sections 9 and 10 along the sections 9 and 10. In the first instance, as this wave approaches the oscillations generator 4, it is liable to encounter the dead end, because by this time the wave reflected from the hydropneumatic accumulator 2 will arrive along the pipe 3, wherebi the high phase of pressure oscillations therein will be terminated. Conversely, in the second instancel as this new wave of high pressure arrives to the pressure relief nozzle cl 1 8. the escape velocity of the flow will increase still further, whereas the pressure in the wave will reduce remaining, however, substantially higher than that in the zone of the flow switch 6 previously (normally higher than the atmospheric pressure). As a result, the pistons 20 and 21 with the rod 22 will move toward the after-piston cavity 24. The piston 20 will depart from the seat 16, and the piston 21 will scat in the seat 15. The pressure relief nozzle 8 will close, and the work- ing nozzle 7 will open. This will lead to a sudden deceleration of the flow and increase in pressure to the maximum. A new high phase of flow oscillations will be initiated in the section 9. Water will escape at the maximum pressure from the working nozzle 7 to the ob- ject to be hjdraulicked, whereafter the operation sequence will be repeated. The hydropneumatic accumulator will initiate operation under steady self-oscillations.

When the number of low pressure waves (in the low phase) in the pipe 3 is more than two, the sequence will proceed as heretofore described until a discontinuity of the flow takes place as the waves from the point of connection between the sections 9 and 10 encounter the dead end.

An increase in the number of waves in the low phase is accompanied by an increase in the escape velocity of the flow from the pressure relief nozzle, and consequently by a growth in pressure in the space before the working nozzle 7.

In view of the aforegoinst the arrangement of the second pipe 5 in the form of two sections 9 and 10 of various diameters makes it possible to accumulate a definite quantity of water in the high phase of oscillations under an increased pressure and ensure an extra acceleration of the liquid in the low phase of oscillations during the escape of water through the relief nozzle 8. Preferably, the ratio oetween the diameters of the sections 0/ and 10 is 2:1. If the diameter of the section 9 is less than two times the diameter of the section 10, accumulation of water under high pressure will be insufficient. With such a ratio between the diameters of the section 9 and 10 in tne low phase of oscillationst and with the preferred ratio between the diameters of the working nozzle 7 and relief nozzle 8 of 1:3 no water acceleration to the maximum velocity will be possible, which eventually affects the amplitude of high pressure in the pulse. The amplitude will therefore be low. In an alternative case, when the diameter of the section 9 is greater than the diameter of the section 10 by a factor of more than 2g the second pipe 5 will tend to accumulate an excessive amount of water under high pressure, whereby in the low phase of oscillations this quantity of water will fail to be accelerat.ed to the maximum possible velocity. This will be accompanied by a pressure drop in tile section 10 to result in reduced amplitude of high pressure in the pulse. Consequently, only the preferred ratio between 11 C ( the diameters of the sections 9 and 10 of the second pipe 5 ensures accumulation of the required quantity of water in the high phase under high pressure to accelerate water in the low phase of pressure oscillations to the maximum velocity and obtain the maximum high pressure amplitude in the pulse.

The preferred diameter of the relief nozzle three times the diameter of the working nozzle 7 is dictated, in the first place, by acceleration of water in the se- cond pipe 5 to the maximum possible velocity, and secondly, by the need to ensure reliable operation of the flow switch 6. VVith this ratio of over three the water will accelerate to a velocity exceeding the maximum. Therewith, tne pressure in the zone of the flow switch 6 will drop suddenly, whereby the movement of the pistons 20, 21 witn the rod 22 and opening of the working nozzle 7 will not be ensured. Conversely, with this ratio being less than three, no sufl-icient acceleration of water will be attained, whereas the high pressure amplitude in the pulse durinG opening the working nozzle will be low.

In view of the aforedescribed, the preferred parameters of the proposed hydraulic pulse generator ensure the maximum high pressure aiiplitude in the 2.5 pulse through increasing the f low rate of water through the hydraulic pulse generator to consequently resul t in a higher efficiency of hydraulicking.

Tile proposed embodiment of the hydraulic pulse 1 generator ensures an increase in the efficiency of bydraulicking thanks to increasing the high pressure amplitude in the pulse and a higher rate of water flow througli the machine.

c 1 z ( 1 41 2C. r, Z09

Claims (3)

1. A tiydraulic pulse generator comprising a supply pipeline having mounted thereon a hydropneumatic accumulator communicating by way of a first pipe with an oscillations generator which coinwunicates by way of a second pipe with a flow s,,,iitch including a working nozzle and a relief nozzleg the second pipe being made up of' two sections of different diameters, the diameter of 1() each preceding section being twice the diameter of each succeeding section in order to form a flow with various phases of pressure oscillations.
2. 2. A hydraulic pulse generator comprising a working- nozzle and a relief nozzle having a ratio between their diameters of 1:3 in order to form a flow with various phases of pressure oscillations.
3. 3. A hydraulic pulse generator substantially as heretofore described with reference to the accompanying drawinGs.

   Platlished 19BE at The Patent Office. Sta:,. Hcuse 66 71 H2:"_::m Lcndon WC1R 4TF Further copies inay be obta---e:l frcin The Patent Of',ce 6ales Branch, St Mary Cray, Orpington. Kent BR5 3RD Printed by Multiplex techniques ltd. St Mary Cray, Ken--- Con 1 87 6ales Branch, St Mary Cray, Orpington. Kent BR5 3RD Printed by Multiplex techniques ltd. S, Mary Cray. Ken--- Uor. 1 b.1