US2162541A - Hydraulic apparatus - Google Patents

Description

June 13, 1939.

G. H WALKER:

HYDRAULIC APPARATUS Filed Jan; 22', 1937'.

3- Sheets-Sheet. 1

Figi A B -w INVENTOIR Seem June .13, 11939.

.G. .H. "IWALKIER HYDRAULIC APPARATUS Filed .Jan. :22, 19:57

3 Sheets-Sheet 2 INVENTOR June 13, 1939. -G. H. WALKER HYDRAULIC APPARATUS 3 Sheets-Sheet 3 Filed (Jan. 22, I937 INVENTOR V q? v eoJwlj Mal/m Patented June 13, 1939 HYDRAULIC APPARATUS George Henry Walker, Worcester, England, as-

signor to-Heenan & Froude Limited, Worcester,

England Application January 22, 1937, Serial No. 121,190

In Great Britain February 6, 1930 8 Claims. (01. 188-90) This invention relates to improvements in hydraulic apparatus of the type comprising primary andsecondary vaned members such as is well known can be employed for the absorption and indication of power as in the ease of absorption brakes and absorption dynamometers and for the transmission of power as in theease of hydraulic couplings.

When such' apparatus is constructed for use as a brake the secondary vaned element is anchored against rotation while the primary element is driven by the source of power tobe braked; when constructed for use as a clutch both elements are free to rotate while transmittingpower at different rotational velocities and.

when constructed-for use as a dynamometer the casing or secondary vaned element is attached to a measuring device which restrains its movement andindicates the torque transmitted thereto.

It is' 'usualto provide the apparatus with means for varying the transmission or absorption capability thereof by varying the degree of filling .of the apparatus which may be effected by controlling the rate of influx or efflux of the hydraulic liquid to or from the elements, such means being described for example in the specification of prior U. 8. Patent No. 1,035,700.

Under running conditions of the apparatus the liquid tends to emerge from the interior to the exterior of the elements under the influence of a pressure self-generated within the working compartment and this pressure increases as the relative speed of the elements or the absolute speed of the primary element increases.

This increase in pressure will for a given outlet opening, cause the outlet rate to increase, so that if the inlet rate remains constant, the working compartment will tend to empty itself of liquid. Thus the transmission or absorption capability of the apparatus will decrease as the speed of the prime mover increases, which is undesirable, as it will cause the prime mover to race.

It is known that if it were possible to keep the volume of water in the working compartment constant despite changes of speed, then the load exerted by the dynamometer would follow well known hydraulic laws. The pressure of water in the working compartment would vary as the square of the speed and the torque developed by the dynamometer would also vary as the square of the speed of the dynamometer shaft.

The object of the present invention is to control the outlet of the liquid from the apparatus so as to maintain a constant amount of liquid in the working compartment thereof despite changes in speed of the primary element. and

ithas been found that provided the pressure of water in the working compartment varies as the square of the speed, then the quantity of liquid contained in the working compartment will remain constant, 6 despite alterations in speed; and, further, the torque developed by the dynamometer will also varyas the square of the speed.

According to the invention a valve is arranged in the outflow from the working compartment 10 of the apparatus and is controlled automatically in accordance with variation in 'speed of the primary member the arrangement being such that for any increase in speed of the primary member above the normal speed the valve is moved from 15 its normal position towards its closed position so asto maintain a constant volume of liquid in the working compartments. r The invention will be described with reference to the accompanying drawings in which: 20

Fig. 1 15.9. diagrammatic view illustrating the- -principle of the invention, the valve in the outlet being controlled by liquid. circulated by a pump or the like driven at a speed proportional to that of the primary element of the dynamometer, brake or clutch.

Fig. 1a is a section ofthe type of hydraulic apparatus to which the invention relates showing the primary and secondary vaned members.

Fig. 2 is atransverse section of a hydraulic brake with the invention applied thereto and showing a hand operated valve for the setting of the normal power absorbing or transmitting capability of the apparatus.

Fig- 3 is a detail sectional the hand operated valve shown in Fig. 2.

Fig. 4 is a detail, sectional view, of another form of outlet control valve in combination with a hand operated valve for the setting of the normal. power absorbing or transmitting capability of the apparatus.

Figs. 5 and 6 are detail. views. of a reversing valve box arranged between the pumpdriven from the shaft of the primary rotor of the brake; clutch or dynamometer and the speed controlled v'alve whereby the liquid controlling the latter will always flow in the same direction whether the rotor is rotating in one direction or the other, the section being taken on line 5-5 Fig. 2;

Fig. 'I is a transverse section showing the invention applied to a hydraulic dynamometer similar to that described in specification of U. S. Patent No, 1,627, 586 and having an' automatically controlled valve operated-on any variation in torque of the 'dyna'mometer. as

view of one form of 35 Figs. 8 and '9 are detail sectional views of the automatically controlled valve.

Fig. 10 is a diagrammatic view showing a modification of the invention in which the pump circulating the liquid controlling the valve in the outlet is replaced by the primary element of the apparatus.

The invention relates to hydraulic apparatus of the type shown in Fig. 1a having a primary vaned member T formed with cups t and a secandary vaned member W formed with co-acting cups 10 comprising the working compartments.

The essential feature of the invention and its manner of operation will be best understood from the diagrammatic view shown in Fig. 1. A valve A of disc or mushroom type is arranged in the egress B from the working compartment of the hydraulic apparatus and when this valve is closed the flow of liquid from the apparatus is prevented while when the valve-is partially open liquid will flow past the valve to the outlet C connected either to a drain or to a storage reservoir from which the water is recirculated through the apparatus. The valve A thus controls the quantity of liquid in the apparatus.

The valve A is connected by a rod a to a flexible diaphragm D or a piston arranged in a vessel E separating it into twochambers e 6 The chamber .6 is in communication with a pump F driven at a speed proportional to that of the primary element of the apparatus either by being geared to or having its impeller mounted on the shaft thereof. The discharge side of the pump F is directly connected with the chamber 6 and the suction side I of the pump is connected with the chamber e through a valve G and strainer H. Thus one side of the diaphragm D is exposed to a pressure varying with the speed of the pump F and consequently with the speed of the primary element of the apparatus.

The valve G is preferably of the needle type capable of giving close adjustment of the resist ance to flow of the liquid. A by-pass having a spring-loaded relief valve K inserted in it also connects the pressure chamber e with the pump suction, so as to prevent the diaphragm D being accidentally subjected to too great a pressure. An expansion chamber L is preferably in communication with the connection between the valve G and the pump F, the chamber L containing a suitable supply of the circulating liquid.

The chamber e at the other side of the diaphragm D forms a low pressure chamber communicating as shown in Fig. l with the suction side I of the pump F through the strainer H.

When working the pump F discharges liquid into the pressure chamber 2 at a rate proportional to the speed of revolution of the primary element of the apparatus the differential pressure between the chambers e and e being determined by the throttling effect of the valve G. By fully opening the valve G,.the pressure maintained in the chamber e relative to that in the chamber c is caused to fall to a minimum, thereby causing the diaphragm D to rise to its highest position and the valve A to be widest open thereby opposing minimum back pressure against the outflow of liquid from the egress B and causing the apparatus to absorb or transmit minimum power. When the valve G is partially closed the pressure in the chamber e relative to that in the chamber e will be increased and the diaphragm D will fall to an intermediate position and the valve A to be partially closed. When the valve G is nearly closed the pressure in the chamber e relative to the chamber e willbe at a maximum and the diaphragm D will fall to its lowest position and the valve A be closed or almost closed thereby causing the back pressure against the outflow of liquid from the egress B to be at a maximum and consequently the power absorbed or transmitted by the apparatus to be a maximum. Intermediate settings of the valve G between the two extremes will have intermediate efiect on the absorption or transmission capability of the apparatus. The valve G thus serves to set the normal absorption or transmission capability at which it is desired the apparatus should work.

Since however any variation of the speed of rotation of the pump F, after the valve G has been set to give the desired normal differential pressurebetween the chambers e and e will create an alteration of pressure in the chamber e and as the speed of the pump is proportional to that of the primary element of the apparatus it follows that any increase in speed of the latter will cause the valve A to close to some extent thus reducing the outlet opening.

It will thus be seen that for any given setting of the valve G any increase in speed of the primary element of the apparatus above normal will cause the valve A to move from its normal position towards the closed position, thus opposing the tendency for the increased internal pressure to increase the outlet rate.

The liquid content of the apparatus thus remains unaltered despite the increase in speed and this is true whether the rate of inflow into the working circuit remains constant or increases; for assuming the rate of inflow to increase above a given normal, momentarily increasing the liquid content of the apparatus, the pressure in the apparatus will increase and cause the valve A to open sufficiently to restore the pressure in the working circuit to normal.

By connecting the low pressure chamber e to the suction side f of the pump F the difference of pressure between the two sides of the diaphragm D is that created by the pump and is independent of the height of liquid in the expansion chamber L and consequently variations in pressure closely proportional to variation in speed are obtained.

The combined weights of the diaphragm D- or piston, the rod a and the valve A are balanced by a spring D Thus the valve A will be moved from its normal position as soon as the speed of the primary element increases above the normal.

' The form of the invention shown in Figs. 2 to 6 is slightly different from the diagrammatic form shown in Fig. 1 in that the outlet from the valve G communicated with the strainer H and suction side I of the pump not directly but indirectly through the low pressure chamber e The pump F (which is illustrated as a gear pump although a centrifugal pump could be employed) is arranged in a casing F and is driven from the primary shaft 111. of the apparatus M through the gearing m and shaft m at right angles to the shaft m.

The vessel E divided into a high pressure chamber e and low pressure chamber 2 by the diaphragm D is bolted or otherwise affixed to the pump casing F, the diaphragm D being connected by the rod a to the valve A controlling the flow of liquid from the outlet B to the pipe C. The high pressure chamber e is connected to the discharge side of the pump F through the greases 3 port e and to the suction side through the valve against the upward pull of the spring D. After G the outlet port a of which opens into the low I the predetermined difference of pressure above a pressure chamber e. A port in the chamber the normal has been reached any further ine' is connected. by the du t'h, strainer H and crease in pressure between the chambers e and s ducts hi and e to the sutxixon side of the pump. e! to rise rapidly tending to close the valve A s A reversing valve N is. p erably arranged beagainst the outflowing liquid and creating a cortween the pump F and the pressure chambers respondingly rapid increase of pressure in tih e and e, the ports of the chamber e being .wcrklng compartment of the apparatus .thisinconnected by the duct e to the discharge chamecreasing the resistance to rotation of the primary/ l0 ber n of this valve N whilst the outlet from the element and enabling the apparatus to govern 10, strainer H is connected to the. suction chamber within reasonably close limits the speed of rota- 11 of the reversing valve N. The duct is. is also tion of the shaft to which the primary element is connected to the expansion chamber 13. connected. g

The port a of the needle valve G is opened The apparatus above described with reference and closed by the rotation of the hand wheel G1. to Figs. 2 to 6 is applicable as an hydraulic brake, 5. The reversing valve N is necessary with. appahydraulic dynamometeror hydraulic clutch but ratus the primary element of which lsadapted 'the apparatus shown in- Figs. 7 to' 91s applicable to rotate in either direction to maintain the port only to. a hydraulic dynamometer. It is designed e in the high pressure chamber e always in to provide a. dynamometer which can be used communication with the discharge side of the either for testing engines having their own speed 0 P mp F and the P e in the w D e-m ehemgovernors by which the speed of the engine and be! 8 always in communication with the suction gonsequently of the dynamometer is maintained sic: of h P p irrespeeflve 0f the direeiil? constant or for testing ungoverned engines. of rotation of the latter... In this construction in addition to the hand The reversing valve Nis shown in F 8 5 end operated valve G for setting the normal power 25 6, the former showing the direction of fl 0t absorption capability of the dynamometer, for a the liquid therethrough when the wheels of the u it an ungovemed engine the chambers. 1 pumngF are rota ing in o e dir n d the ande' are connected through an automatically latter. showing the directionofdiow when the controlled valve P preferably of the balanced I 80 wheels are rot g in the pp direeuonpiston type arranged in parallel with the valve G. so.

When the wheelsof the pump 1'' r r fl When used for testing an engine having its own. in the. direction shown by the arrows I, Fig. 5 the. speed governor and t speed of which therequ d enters f m h st n Hi through t fore remains constant; the valve'G is closed so suction chamber 11* lifts the ball valve n and thatall the liquid discharged by the circulating ll pass s t h p e n. It is then carried round pump passes through the, valve P which is autoas by the teeth of the gear pump 1' to the space n "matically controlled to vary the opening of the opening the ball valve n and passes by the duc valve A on any variation in torque of the dynan to the pressure chamber n connected to the mometer thereby automatically maintaining the port e of the hi h Press chamber a of the torque constant. a T

40 vessel E and from thence through the needle Fig. 7 shows this arrangement applied. to a 40 valve G and chamber e back to the strainer H. reversible dynamometer M capable of absorbing when the direction of rotation of the wheels of power in either direction of the type described the pump F is reversed as shown by the arrows 2 in the specification of U. 3. Patent No. 1,627,586

in Fig. 6 the pr s u e o l 0f e a valve being controlled through a system of levers from n keeps 'the latter closed but opens the ballvalve the weight arm m pivotally mounted 'at m'on a 45 n" which was previously held closed and the liqvertical rod m whereby the opening and closing uid ent rinsfrom'the strainer H at 11 passe 'of the valve is controlled by the oscillation of through the valve n to the wheels of .the pump the casing M of the dynamometer, the torque F, is carried by the teeth of the latter from the reaction upon which is balanced by the weights 60 space M to the space '11 lifts the ball valve n M suspended from the arm. m In such congo and so passes to the discharge chamber 11. struction" of dynamometer" the casing M is As shown in Fig. 3 the casing for the relief formed with trunnions m carried upon rollers m valve K is attached to the Valve G the inlet p 9 to permit the casing to oscillate freely and the of the latter being connected to the port I: of the casing is connected to the pivoted weightarm m former. The valve K comprises a ball 7: conby a system of levers and links m and connect- 56 trolled by a spring k whereby should the presing rod m to the top m of which the arm m is 'sure of the liquid rise above the pressure of the pivoted whereby the arm m will move to raise spring k the ball will be lifted from its seating the weights M on an increase in absorption of and the liquid can then pass through a passage power by the casing irrespective of the direction 60 (not shown) to the chamber e. of rotation of the rotor of the dynamometer. so

Inthe construction of the valve A shown in As before stated the valve P is of the balanced Fig.4 the combined weights of the diaphragm D; piston type and the rod p carrying the pistons valve rod is and the valve A are as, previously :2 and p is connected by the links and levers p stated balanced by a spring D so that the valve 1: and p to the weight arm m of the dyna- 05 will be operated immediately there is any inmometer. The linkp is pivotally mounted at its so creasein pressure on the top of the diaphragm lower end on the arm m and-its other end is but in the construction of valve shown in Fig. 2 adjustably mounted in a slotted quadrant p on the valve A is normally held open by a spring D the lever 11*. The lever 12* is pivoted at p" and which is of such strength that the'valve A is not its other end is pivotally connected to the link' i0 moved by an increase in pressure in the chamber p attached by the pin 1) to the piston. rod p. ,e relative to the chamber a caused by an in- 'The valve P is formed with two ports P and P crease in the speed of the primary element until the port 1 being connected to the suction chamsuch increase of pressure above the normal has her or port 11 of a reversing. valve N such as reached a predetermined value of suflicient hereinbefore described and the port p through v amount to iorce the diaphragm downwards the chamber e to the discharge chamber or port 75 it about its trunnion supports m and to lift the weights M thereby moving the arm m about its fulcrum. This movement of the arm m is communicated through the links and levers 12 p and p to the valve rod pwhich causes the latter to rise and ,the port P to open thereby reducing the difference in pressure at the ports n and n.

detents R This reduces the pressure on the diaphragm D and allows the valve A to open, whereby the consumption of power in the dynamometer is diminished until the torque is reduced and the arm m returns to its normal position of equilibrium whereupon the port P is closed, the pressure on the diaphragm is decreased and normal working resumed. Thus torque resisting rotation of the shaft of the dynamometer M is maintained constant irrespective of changes in speed of the dynamometer shaft.

To facilitate the'use of the dynamometer in rapidly applying or removing load to or from the engine i. e. for varying the normal torque of the dynamometer, the pivot p of the lever 11 is mounted upon an eccentric R secured to a quadrant R by a hand lever 1'1. and spring loaded By pushing the lever R? in the direction indicated by the arrow r in Fig. 8 the eccentric R. is caused to rotate ,through part of acircle, thereby lifting the lever p and raising the point of attachment to the link :1 simultaneously opening the ports P and relieving the back pressure and consequently the torque exerted by the dynamometer. Motion of the hand lever in the opposite direction tends to close the port P and consequently increase the torque.

In Fig. l the pump is shown mounted on the casing of the dynamometer and is connected to the valve P by connections S and S the flow of liquid being from the pump F through the reversing valve N to the valve P and simultaneously to the high pressure chamber e of the valve A.

Although the pump F has been hereinbefore described as a gear pump a centrifugal pump may be employed or the primary rotor of the apparatus may itself control the pressure on the two sides of the diaphragm D such a construction being shown in Fig. 10.

In the construction shown in Fig. 10 the primary element T of the apparatus is formed in the usual way with cups t and in addition with vanes t on the rim for the purpose of maintaining rotational circulation of liquid in the annular space between the rim of the rotor T and the casing M direction of rotation being counterclockwise as shown by the arrow t An open ended tube V is inserted into this annular space, its open mouth pointing tangentiallyagainst the direction of rotation and a second openended tube V is arranged radially so that its mouth projects into the casing at about the same radial distance from the axis of rotation as the mouth of the tube V.

The outer end of the tube V is connected by ports, passages or piping to the high pressure 2,162,541 n thereof. The pistons p and p are of conical compartment of the valve A and the tube V is connected to the low pressure compartment. When the rotor T of the apparatus rotates in the direction of the arrow 1. the working liquid impingeson the open end of the tube V which conveys to one side of the diaphragm D a pressure equal to the sum of the static and dynamic heads whilst the tube V communicates to the low pressure chamber the static pressure only, so that the diaphragm D which separates the two chambers is subject to the difference between these liquid pressures i. e. to dynamic head only.

As previously explained the normal magnitude of this liquid pressure is controllable by the valve G which communicates from the high pressure to the low pressure chamber, but for any given setting of the valve G the differential pressure upon the diaphragm and consequently the resistance to the outlet of liquid from the working compartment of the apparatus increases with any increase in the speed of rotation of the primary element, above the normal speed.

I claim:

1. Hydraulic apparatus of the type referred to comprising primary and secondary vaned members forming working compartments having in combination with the liquid.outlet of the apparatus, a valve arranged in the said outlet, a fluid operated diaphragm controlling said valve, and means driven by the primary vaned member for automatically varying the pressure of the fluid on one surface of the diaphragm relative to the other in accordance with variation in speed of the primary vaned member to vary the opening of the valve to maintain a constant volume of liquid in the working compartments.

2. Hydraulic apparatus of the type referred to comprising primary and secondary vaned members forming working compartments having in combination with the liquid outlet of the apparatus a valve. arranged in the said outlet, a fluid operated diaphragm controlling said valve, a vessel in which the diaphragm is located and-is separated thereby into two chambers-a low pressure chamber and a high pressure chamber and a pump geared to the primary vaned element, the

high pressure chamber being connected to the delivery side of said pump and-the low pressure chamber to the suction side thereof so that the pressure of the fluid on the high pressure side of the diaphragm relative to the pressure of the fluid on the low pressure side is varied in accordance with variation'in speed of the pump and consequently of the primary vaned member to vary the opening of the valve to maintain a com stant volume of liquid in the working compartments.

3. Hydraulic apparatus of the type referred to comprising primary and secondary vaned members forming working compartments having in combination with the liquid outlet of the apparatus a valve arranged in the said outlet, a fluid operated diaphragm controlling said valve, a vesselin which the diaphragm is located and is separated thereby into two chambers, a low pressure chamber and a high pressure chamber, a pump geared to the primary vaned element, the high pressure chamber being connected to the delivery side of said pump and the low pressure to vary the opening of the valve to maintain a constant volume of liquid in the working compartments, and a hand operated valve between the high pressure chamber and the low pressure chamber for the purpose of varying the normal pressure difference between the twochambers for setting the normal power characteristic ofthe apparatus.

4. Hydraulic apparatus of the type referred to comprising primary and secondary vaned members forming working compartments, having in combination with the liquid outlet of the apparatus, a valve arranged in the said outlet, a fluid operated diaphragm controlling said valve, a vessel in which the diaphragm is located and is separated thereby into two chambers-a low pressure chamber and a high pressure chamber, a pump geared to the primary vaned element, the high pressure chamber being connected to thedelivery side of said pump and the low pressure chamber to the suction side thereof so that the pressure of the fluid on the high pressure side of the diaphragm relative to the pressure of the fluid on the low pressure side is varied in accordance with variation in speed of the pump and consequently of the primary vaned member to vary the opening of the valve to maintain a constant volume of liquid in the working compart-' ments, a hand operated valve between theyhigh pressurachamber and the low pressure chamber for the purpose of varying the normal pressure difference between the two chambers for setting the normal power characteristic of the apparatus, and an automatically controlled valve in parallel with the hand controlled valve said automatic valve being controlled by movement of the secondary vaned member whereby on any variation in torque of the latter when the hand controlled valve is closed, the differential pressure on the diaphragm will be varied to move the valve to vary the internal pressure of the apparatus and maintain the torque constant.

5. Hydraulic apparatus of the type referred to comprising primaryand secondary vaned members forming working compartments having in combination with the liquid outlet of the apparatus a valve arranged in the said outlet, a fluid ope'rated diaphragm controlling said valve, a vessel in which the diaphragm is located and is separated thereby into two chambers-a low pressure chamber and a high pressure chamber, a

pump geared to the primary vaned element, the high pressure chamber being connected to the delivery side of said pump and the low pressure chamber to the suction sldethereof so that the pressure of the fluid on the high pressure side of the diaphragm relative to the pressure of the fluid on the low pressure side is varied in accordance with variation in speed of the pump and consequently of the primary vaned member to vary the opening of the valve to maintain a constant volume of liquid in the working compartments, a hand operated valve between the high I pressure chamber and the low pressure chamber for the purpose of varying the normal pressure overcome the pressure of the spring,

difference between the two chambers for setting the normal power characteristic of the apparatus and a relief valve in parallel with'the con- 7 bers forming working compartments having in combination with the liquid outlet of the apparatus a valve arranged in the said outlet, a fluid operated diaphragm controlling said valve, a vessel in which the diaphragm is located and is sep-' arated thereby into two chambers-a low pressure chamber and a high pressure chamber, a pump geared to the primary vaned element, the high pressure chamber being connected to the delivery side of said pump and the low pressure chamber to the suction side thereof so that the pressure of the fluid on the high pressure side of the diaphragm relative to the pressureof the fluid on the low pressure side is varied in accordance with variation in speed of the pumpand consequently of the primary vaned member to vary theopening of the valve to maintain a constant volume of liquid in the working compartments, a hand operated valve between the high pressure chamber and the low pressure chamber for the purpose of varying the normal pressure difference between the two chambers for setting the normal power characteristic of the apparatus, and an automatic reversing valve in the liquid circuit between the pump and the diaphragms whereby the flow of liquid to the pressure chamber is always in the same direction irrespective of the direction of rotation of the primary vaned member and therefor of the pump.

'7. Hydraulic apparatus of the type referred tocomprising primary and secondary vaned members having in combination with the liquid outlet of the apparatus a valve arranged in the said outlet, a diaphragm controlling said valve, a vessel in which the diaphragm is located and is separated thereby into two chambers-a low pressure chamber and a high pressure chamber, a tube arranged tangentially in the space between the primary element and the secondary element with its orifice opening against the direction of rotation of the former, said tube being connected to the high pressure chamber and a second tube arranged radially in the space between the primary element and the secondary element said second tube being connected to the low pressure chamber. a

8. Hydraulic apparatus of thetype referred to as claimed in claim 1 having in combination with the valve and diaphragm a spring which holds the valve open until the difierence in pressure between the two sides of the diaphragm has reached a predetermined amount sufficient to thus preventing the valve from operating until a predetermined speed of the primary member above the normal is attained.

GEORGE HENRY Wm.

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