US906457A - Valve-gear of simplex pumps. - Google Patents

Description

P. P. ODDIB. VALVE GEAR 0F SIMPLEX PUMPS. APPLICATION FILED APR. 18, 1908.

906,457. Patented Dec. s, 1908.

' 3 SHEETS-SHEET 1.

FICJ.

(6f Fla-2. e 2 il P. F. ODDIE.

VALVE GEAR 0F SIMPLEX PUMPS.

APPLICATION FILED APB.18, 1905.

906,457. faten ned Dec.8,1908.

P. F. ODDIE.

VALVE GEAR UP SIMPLEX PUMPS.

APPLICATION FILED APR. 1a, 1908.

Patented Dec. 8, 1908.

3 SHEETS-SHEET 3.

o 0 w w .fi m 4 PHILIP FRANCIS ODDIE, OF WIMBLEDON, ENGLAND.

VALVE-GEAR OF SIMPLEX PUMPS.

Specification of Letters Patent.

Patented Dec. 8, 1908.

Application filed April 18, 1908. Serial No. 427,856.

T all ai /tom it may concern:

Be. it known that I, Pni'mr FRANCIS ODDIE, subject of the King of Great Britain, residing at lVorple road, \Vimbledon, in the county of Surrey, England, engineer, have invented certain new and useful Improvements in the Valve-Gear of Simplex Pumps, of which the following is a specification.

This invention relates to improvements in the valve gear of simplex pumps, in order to secure a more correct and quiet working of the same, both when pumping fluids practically incompressible such as water, where the load on the pump piston, or plunger is practically constant throughout the stroke, and for pumping compressible fluids such as air, where the work done is not constant throughout the stroke, and also for cases where the power developed is not the same for the up for the down stroke, such as when driving single acting air pumps for condensers. and analogous machines.

Referring to the drawings :----l igurc 1 shows a part sectional elevation through the motor cylinder and valve gear of a pumping cngine, constrm-tcd according to the present invention. Fig. 2 is a sectional plan showing the gear, seen at the lower part of Fig. 1. Fig. 3 is a longitudinal section to an enlarged scale through the valve chest, seen externally in Fig. 1. Fig. at is a central transverse section through the valve chest. Fig. shows the distributing valve. Fig. (3 is a longitudinal section of a modified. con struction designed particularly for use when pumping elas ic fluid, and taken through the valve chest of an air pump or the like. Fig. 7 is a transverse section through the valve chest. Fig. 8 shows to an enlarged scale a detail of the gear, seen in Fig. 1, with the parts in a different position.

a is the steam cylinder, (4 the piston, a the piston rod.

7) is the valve chest, having a valve face I), and the usual three openings for a D slide valve, the two side openings or channels If, 7) leading to the respective ends of the main cylinder, while the middle channel. I) leads to the exhaust opening f.

c is the main distributing valve, pro longed at each end to form hollow pistons, c, and having suitable ports or openings n, c, in the circumference and other ports or openings 0" and c which correspond respectively with the channels 6 Z), on the valve face. Caps (Z, (Z, surroundv these hollow pistons with ports or openings (Z (Z and these caps have channels which correspond to ports or openings in the circumferences of the piston valve heads. In addition to these ports or openings 0, c, 0 c in the valve, auxiliary channels d", d lead to the respective ends of the chambers formed by the caps (l, cl.

6 is a cross head attached to themain piston rod (4", which carries the lover or levers 6.

c is the fulcritnn, while 0 and c are tappet pieces or operating parts which are each connected at their opposite ends to the levers by centered connections which admit of a rocking motion. The distance from the fulcrum c to the center of the tappet or cross piece c is considerably less than the distance between the fulcrum e and the center of the tappet or cross piece 6, for the purpose hereafter explained. The abutment or tappet. head 0" is mounted on a rod c and so connected with the main valve c by means of a suitable mechanism that a. reciprocating motion of the rod c will give to the valve 0 an oscillating movement.

In operation, steam is admitted by a steam pipe located say at f, and the steam thence passes freely around outside the caps (Z, (Z, and, presuming the piston to be at the top of its stroke, the steam enters the hollow piston valve 0 by the ports (Z in the cap (Z and the ports c in the valve head 0 and passes thence by the port c and channel I) to the top of the cylinder. The piston will then descend, carrying the cross head 6 with it, which will give to the rod 0 by means of the tappct head 0 and tappet or cross piece a a slow upward motion which will cause the main valve to oscillate.

The relative positions of the ports 0 and (Z at the commencement of the stroke are such that only a comparatively small area is opened for the inflow of steam. The slow oscillating motion of the valve will however increase the area. The piston will therefore start slowly, and the velocity of the piston will increase up to about the middle of the stroke, when the further oscillating motion will cause the area of the ports to decrease, until before the end of the stroke the supply of steam will be cut off altogether.

Just before the end of the stroke the tappet c" comes in contact with the tappet head c, the parts in this position being shown to an enlarged scale in Fig. 8, and owing to the greater distance of the radius of this piece from the fulcrum 0 it will give an increased velocity to the rod 6 and cause a comparatively quick oscillation of the valve. This will put the small ports (Z and (Z one in connection with the exhaust channel, and the other in connection with the live steam supply, causing a change of pressure in the chambers formed by the caps cl and (Z and the main valve will'have sliclable movement and will be reversed. The steam will now enter the chamber 0 of the piston valve by the channels (Z and a and pass from thence by the openings c into the port 6 leading to the under part of the cylinder, while the exhaust from the top of the cylinder passes by the channels 6 into another channel 5* lead ing to the exhaust. The piston now commences to ascend, slowly at first, but as the valve is slowly reciprocated by means of the tappet piece e", the velocity will increase as before to the middle of the stroke and diminish again towards the end thereof. Just before the end of the stroke, the tappet or crosspiece a will give an increased oscillating motion to the valve, and the small ports (F, (Z will again reverse the valve.

- A certain amount of play is allowed between the jaws of the tappet head 6 and the tappet c (as shown in Fig. 7 This play is taken up by the accelerated motion given by the tappet 0*, so that on the return stroke, the tappet e at once begins to oscillate the valve slowly in the opposite direction so as to give an increasing admission.

By slightly turning the caps (Z, (Z, by means of the handles h, h, in the covers I), b, the amount of admission and the point of cut off of steam may be regulated at will while the pump is at work.

So far this invention has been described as applied to pumping incompressible fluids such as water, where the resistance to the up and down stroke is the same, and constant throughout the stroke. For pumping air, the work to be done at the beginning of the stroke is considerably less than that to be done towards the end of the stroke, and in order to provide for this variation. or inequality ports or openings are formed in the cap (Z', (shaped as shown at (Z Fig. 6). Here the admission is small at the beginning of the stroke and increases right up to the end of the stroke, before it is finally cut 05-.

To meet existing conditions, it frequently becomes necessary that pumps must be capable of working with a varying load on the up stroke or the down stroke, that is to say, more work has to be done on the up stroke than on the down stroke, or vice versa. Further the proportion of the work done by the up stroke will vary from that done by the down stroke while the pump is at work. For instance, in a single acting air pump of the type known as the suction valveless type at the commencement of the work, when there is no vacuum or a very low vacuum in the condenser, the work done on the down stroke is very much greater than when there is a high vacuum in the condenser, and would be generally greater than the work done by the up stroke. The present invention performs an essentially novel function in that it renders it easy to compensate for these variations that is to say the admission of the working fluid to one side is regulated by ports and channels which are quite distinct from the regulating devices controlling the corresponding fiuid admission on the other side, while the exhaust channels may always remain the same for both irrespective of the conditions of admission. The simple introduction of the valve m as shown in Fig. 7, admits of the regulation of the pressure of the working fluid of the one side with great simplicity and certainty, quite inde pendently of the working fluid on the other side. Thus for instance in the air pump of the above mentioned type, this valve would at the commencement of the working be fully open, so as to give full pressure of steam for the down stroke/as the vacuum in the condenser increases, the steam will gradually be throttled by the valve, and an equal and even velocity of the piston for the up and down strokes insured, notwithstanding the varying amount of work that is being done.

A prominent and characteristic feature of this invention is the facility afforded for regulation of the amount of steam admission throughout the stroke, so as to secure quiet and even working at all speeds and duties, without in any way interfering with the recognized necessity for the distributing valve to remain undisturbed in its position, after its steamthrown movement, until the stroke has been completed. This effect is insured according to the present invention by reason of the slow oscillating movement of the valve throughout the stroke, controlling the admission which movement at the same time is absolutely distinct from the accelerated oscillating movement produced toward or at the end of the stroke for reversing the ports controlling the auxiliary steam channels, and equally are both the foregoing movements of control absolutely distinct and separate from the steam-thrown movement of the valve itself. Thus may be constructed a simplex pump, the-piston of which starts gradually at the beginning of the stroke and consequently without developing shock on the water column, or pump valves, and further, the admission of steam throughout .the stroke is effectually regulated to meet the demands of the pump. Theinvention further enables the work done on the up stroke to be effectually regulated independently of the work done on the down stroke. or vice versa, avoiding any danger of interference with the certainty of the steai'i'rthrown motion of the main valve at the end of the stroke.

Having now particularly described and ascertained the nature of my said inveir tion, and in what manner the same is to be performed, I declare that what I claim is 1. In valve mechanism of the type set forth, in combination, an engine cylinder, a valve chest having live steam passages communicating with the ends of said cylinder and an intermediate exhaust steam passage, said chest also having live steam spaces, valve caps in said chest having ports to register with said steam spaces, a valve mounted in said chest for oscillating and sliding move ment, said valve having hollow valve heads fitting in said caps and formed with ports to establish connnunication between said steam spaces and the corresponding live steam passages adjacent thereto, said valve also having pressure changing passages extending from its center to the opposite ends thereof, and valve gearing for oscillating said valve to control the ports of said cap and to then establish communication between one of said pressure changing passages and the live steam space and between the other pressure changing passage and the exhaust steam passage.

2. In valve mechanism of the type set forth, in combination, a valve chest, and a valve in said chest having three movements, the first movement being oscillatory and distributive to regulate the amount of steam admitted to the engine cylinder throughout the stroke of the piston, the second movement being oscillating and occurring at the end of the first movement, said valve having means for varying the relative degrees of pressure upon its ends, the second movement accomplishing the cut-off and the change in the relations of the steam-pressure at the ends of the valve, and the third movement being slidable and causing the reversal of the position of the valve, the third movement being accomplished by steam pressure.

In valve mechanism of the type set forth, in combination, a valve chest and a valve in said chest having a cycle of three movements in the stroke of the piston, said valve being constructed to accomplish in said movements in the order named the operations of fluid admission and distribution, tiuid cut off and reversing.

t. In valve mechanism of the type set forth, in combination, a valve chest having two live steam passages and an intermediate exhaust passage. and having two series of steam ports, and a valve constructed to establish communication between one series of said ports and a steam passage and between the other steam passage and the exhaust passage, said valve having a cycle of three movei l l ments in the stroke of the piston, and in its first movement controlling the active size of the steam ports, in its second movement closing said ports and in its third movement reversing the admission of steam, said valve having means operative at the completion of the second movement for changing the rela tive degrees of st am pressure upon opposite sides thereof, said steam pressure accomplishing the third movement of said valve.

in valve mechanism of the type set forth, in combination, a valve chest having two live steam passages and an intermediate exhaust passage, and having two series of steam ports. a valve constructed to establish connminication between one series of said ports and a st-am passage, and between the other steam passage and the exhaust passage, said valve having a cycle of three movements in the stroke of the piston and in its first movement controlling the active size of the steam ports, in its second movement closing said ports and in its third movement reversing the admission of steam, said valve having means operative at the completion of the second movement for changing the relative degrees of steam pressure upon opposite sides thereof, said steam pressure accom plishing the third movement of said valve, and valve gearing including means operat ing during the stroke of the piston to actuate said valve in its first movement and means opcintivc at the completion of the stroke of the piston to actuate said valve in its second movement.

t3. In valve mechanism of the type set forth, in combination, a valve chest having two live steam passages and an intermediate exhaust passage and having two series of steam ports, one at each end thereof, a valve mounted in said chest for oscillating and sliding movements and constructed to establish communication between one series of said ports and a steam passage, and between the other steam passage and the exhaust jiassage, said valve having two movements in one stroke of its oscillation, and in its first movement controlling the active size of the steam ports and in its second movement closing said ports, said valve having means operative at the completion of the second movement for changing the relative degrees of steam pressure upon opposite sides thereof, said steam pressure acting to move said valve slidably at the completion of the second movementaforesaid and to reverse the admission of steam and valve gearing including means for operating said valve in its first movement during the stroke of the piston and means for operating said valve in its second movement at the completion of the stroke of the piston and at a speed greater than the speed of its first movement.

7. In valve mechanism of the type set forth, in combination, a valve chest having two live steam passages, an intermediate exhaust passage and a steam space, valve caps in the ends of said chest having steam ports registering with said steam space, a valve having a head fitting in each cap and constructed with ports to register with said steam ports, each head in one position of the valve establishing communication between said steam ports and the adjacent live steam passage and in another position of the valve establishing communication between said live steam passage and the exhaust steam passage and means for adjust ably positioning each cap to vary the positions of the steam ports therein with relation to the corresponding steam ports of said valve.

8. In valve mechanism of the type set forth, in combination, a valve chest having two live steam passages, an intermediate exhaust passage, and a steam space, members in said chest having steam ports registering with said steam space, a valve having a head associated with each member and constructed with ports to register with said steam ports, each head in one position of the valve establishing communication between said steam ports and the adjacent live steam passage, and in another position of the valve establishing communication between said live steam passage and the exhaust steam passage, and means for adjustably positioning each member to vary the positions of the steam ports therein with relation to the correspondin steam ports of said valve.

9. In valve mechanism of the type set forth, in combination, a valve chest having two live steam passages, and an intermediate exhaust steam passage, members in said chest having steam ports, said chest hav ing a steam space for each member, a valve having a head associated with each member and constructed with ports to register with said steam ports, each head in one position of the valve establishing communication between said steam ports and the adjacent live steam passage, and in another position of the valve establishing communication between said live steam passage and the exhaust steam passage and a pressure controlled valve interposed in one of said steam spaces.

10. In valve mechanism of the type set forth, in combination, a valve chest having two live steam passages and an intermediate exhaust steam passage, valve caps in the ends of said chest having steam ports, said chest having a steam space surrounding each valve cap, a valve having a head fitting in each cap and constructed with ports to register with said steam ports, each head in one position of the valve establishing communication between said steam ports and the adjacent live steam passage, and in another position of the valve establishing communication between said live steam passage and the adjacent exhaust steam passage and a pressure controlled valve interposed in one of said steam spaces.

11. In valve mechanism of the type set forth, in combination, a valve chest having two live steam passages and an intermediate exhaust steam passage, members in said chest having steam ports of substantial triangle shape, said chest having a steam space for each member, and a valve having a head associated with ,each member and formed 7 PHILIP FRANCIS ODDIE.

WVitnesses ALFRED GEORGE BROOKES, ERNEsT JOHN HILL.

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