US2867893A - Descaling apparatus for forging ingots - Google Patents

Description

Jan. 13, 1959 A. o. ANDRESEN ETAL 2,857,893

DESCALING APPARATUS FOR FORGING INGOTS Filed Sept. 1, 1955 6 Sheets-Sheet 1 J4 /Z- Z Ji' E- /Z:M;%%*QM Jan. 13, 1959 A. o. ANDRESEN ET AL 2,

DESCALING APPARATUS FOR FORGING INGOTS 6 Sheets-Sheet 2 Filed Sept. 1, 1955 INVENTORS Jan. 13, 1959 A o. ANDRESEN EIAL DESCALINGYAPPARATUS FOR FORGING INGOTS 6 Sheets-Sheet 3 Filed Sept. 1, 1955 I I'll lllllll lllllvlllllllllllvllllllllllllliuilll nvmvronsj 0. irrafres'ew Jan. 13, 1959 A'. o. ANDRESEN ETAL DESCALING APPARATUS FOR FORGING INGOTS 6 Sheets-Sheet 4 Filed Sept. 1, 1955 e 4 TH M? w m e 1 Q 4 \\Smw e e "V. r s I Wu W N WM WM.

Jan. 13, 1959 A. o. ANDRESEN ET AL 2,867,893

DESCALING APPARATUS FOR FORGING INGOTS Filed Sept. 1, 1955 6 Sheets-Sheet 5 INVEN TORS.

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DESCALING APPARATUS FOR FORGING INGOTS 6 Sheets-Sheet 6 Filed Sept. 1, 1955 egIVVE/VTORS firrre 0, A rese 7-1 f argi esf 7Fe 2771 4712? i'ra DESCALING APPARATUS FOR FORGING INGOTS Arne O. Andresen, Lansing, and Forrest A. Reinhart,

Dearborn, Mich.

Application September 1, 1955, Serial No. 531,928

7 Claims. (Cl. 2981) The present invention relates generally to apparatus for descaling hot metal preparatory to forging, rolling and other die-forming operations. More specifically the present invention relates to a compact, self-contained apparatus of this type which may be made portable, if desired.

In the forging industry and in the steel rolling mills, billets and ingots usually are descaled before being placed in the forge dies, or before being passed through the rolls. The reason for this is that metal scale is an extremely abrasive material which will quickly wear out dies and rolls. Descaling has usually been carried out by spraying the hot metal with high pressure water to cause a skin cooling effect whereby the scale contracts more than the hot base metal, it cracks, water gets under it, vaporizes explosively and removes the scale. The scale is then washed away by the impingement forces exerted by the high pressure water. The apparatus available for carrying out this operation has been so massive and expensive that small forge shops have usually operated without descaling, thereby making their die costs prohibitively high.

One reason for the extremely large size and high cost of prior descaling apparatus has been the necessity to employ extremely large water pumping units capable of delivering a sustained stream of water with little drop in pressure. The size and weight of such pumping units has required either that they be permanently installed at or near each forge press or be sufficiently large to be centrally located with water supply lines extending to individual descaling units located near the presses. In either case their cost of operation is prohibitive to the small shop. it would be highly advantageous in all sizes of shops if small and compact, self-contained descaling units were available'that are inexpensive to build and operate and which are either portable or so small as to be easily moved from location to location as required by the changing needs of the business.

It is an object, therefore, of the present invention to provide a compact, self-contained descaling apparatus.

Another object is to provide an-apparatus of the type described which is portable.

Still another object is to provide such an apparatus which employs a novel pumping unit of compact size yet which is capable of delivering a sustained stream of high pressure water without appreciable pressure drop.

Yet another object is to provide such an apparatus which is safer to shop personnel by reason ofnot requiring electric motors.

It is also an object to provide a descaling apparatus which does not require sewer connections by reason of its incorporating a recirculatory water supply system.

Other objects and advantages of the present invention will be apparent, or will become apparent in the more detailed description to follow which is taken in conjunction with the accompanying drawings.

In the drawings:

, Figure 1 is a front elevation, with portions broken away and in section, of the descaling apparatus of this invention;

Fig. 2 is aside elevation'of the apparatus'of'Fig. 1,

United States PatentOfilice g Jan,

with portions broken away and in section, the view being taken in the direction of the arrow 2 in Fig. 1;

Fig. 3 is an elevational view, with portions broken away and in section, of the other side of the apparatus, the view being taken in a direction of the arrow 3 in Fig. 1;

Fig. 4 is a schematic view of the apparatus shown in Figs. 1 to 3, the view representing the condition of the apparatus before the ingot or billet has been inserted and wherein the water accumulator ram has been refilled and is ready to deliver water to the spray ring;

Fig. 5 is a view similar to Fig. 4 but representing the condition just after a billet has been inserted therein and the water accumulator ram has started to deliver water to the spray ring; and t Fig. 6 is an enlarged longitudinal section through the double-ended, air-actuated pump used to refill thewater accumulator ram.

In accordance with the present invention a descaling apparatus is provided which is self-contained and which employs a combination of a water ram and a fluid accumulator to supply a sustained stream of water without appreciable pressure drop. The water ram is piston-operated and is in open communication with the fluid accumulator in order that the ram piston be actuated by an essentially constant pressure of fluid and thereby be enabled to deliver water at an essentially constant rate and pressure. The ram cylinder is arranged to be recharged by what is, in effect, a second fluid-operated ram operating in opposition to thefirst ram, this arrangement conserving operating fluid and allowing the maintenance of full operating pressure on the fluid accumulator by a small fluid supply system through relatively small fluid supply lines. The descaling spray ring is enclosed in a cabinet so as to collect unvaporized water, the collected water flowing to a storage tank where it is drawn upon to refill the water ram. Only make-up water need be supplied to such storage tank and the apparatus thus requires only two connections, one to a source of operating fluid such as air and the other to a water supply line. No sewer connections, which are virtually impossible to maintain in a forge shop, are required by such a self-contained unit.

Referring now to thedrawings, it will be seen, Figs. 1 to 3, that the apparatus comprises a more or less rectangular-shaped cabinet 10 of metal plate mounted on angleshaped skid runners 12. As appears most clearly in Fig. l, in the upper high- hand corner partitions 14, 16, 18 and the front wall 20 of the cabinet form a closed descaling compartment 11 in which is mounted a circular spray ring 22, the latter being mounted just in back of the front cabinet wall 20. In the latter an aperture 24 is provided through which billets or ingots are inserted to pass through the spray ring 22. More will be said about the descaler cabinet below.

On the left-hand side of the apparatus, as viewed in Fig. 1 and toward the front of the outer cabinet 10, a bottom partition 26, an end partition 28, the partition 14, a top wall 29 and the front wall 20 of the outer cabinet 10 form a closed pump and valve compartment 30. Beneath the bottom partitions 16, 26, the central. space at the bottom of the outer cabinet 10 is occupied by a cylindrical air tank 32. An air supply line 34, containing a pressure-regulating valve 36 and a pressure gauge 38, is extended through the back wall 40 of the outer cabinet 10 to make connection with the air tank.

The space between the air tank 32 and the bottom portion of the outer cabinet 10 functions as a water supply orreservoir tank 13. As shown in Fig. l, a removable.

scale trap tank 42 is supported on brackets 43 on the outside of the outer cabinet 10 with a longitudinal slot 44 in the outer cabinet wall being provided to allow Waterto flow into the trap tank 42 from the descaling or spray water to overflow into the reservoir tank 13 of the cabinet.

As appears in Figs. 1 and 2 a float 46 and valve 48 connected'with a'water-inlet pipe '50 -areprovided in the bottom of the cabinet to maintain a constant water level'in the water tank 13 which is lower thanthat in the trap tank42. Unvaporized water carrying suspended scale flows down the slanted bottom partition 16 of thedescaler enclosure 1-1 t drop into the trap tank 42 wherein the scale 54 "settles to the bottom and the clear water overflows through pipes 45, 47 into the interior of the cabinet. A lip 52, 'formed in the outer edge of partition 16 serves to guide the water intothe trap. When the accumulated scale 54 in trap 42 must be disposed of, the trap tank 42 can be removed from =the'brackets 43 for emptying.

-Also-on the left-hand side-of =theouter cabinet and to the rear of the pump and valve compartment 30 there is mounted a piston cylinder 60 having a large actuating piston-62 connected to apiston rod=64. The bottom end 66 of the piston rod 64, which serves as a water ram, is -extended downwardly to fit into a ram cylinder 68 secured in axial alignment with the piston rod '64. A large air inlet line 70 connects the top side of piston 62 with the air accumulator tank 32. No valves are provided in line 70, the latter always being in open communication with the tank and piston so that the latter is always under air pressure. As shownin Figs. 4 and 5, the 'bottom side of piston-62 is always open to atmosphere through an aperture 72 so that no back pressure will be exerted thereon. More will be said about the water ram 66 and its actuating piston below.

Water is drawn (Fig. 3) from the water tank through a line 80, a water strainer 82, and line 84, the latter having two branches 84a, 84b connected to the opposite sides 'of a double-ended air-operated water pump 86 through check valves '87 and inlet ports 88, 90. The pump '86 '(Fig. l) discharges the water from each its ends through 'a check valve 92, line '94, an 'angle check valve 96 and line 98 to the bottom end of the water r-am cylinder68. Line 98 also serves as a discharge line for the cylinder 68, check valves 92, 96 serving to block back 'flow to the pump 86 to allow the water to be discharged through line 100 '(Fig. 4) to a water release valve 102 "having a'pilot operator 104. Water is released from valve '102 directly to the spray ring 22 which is coupled directly to the release valve by means of a short pipe connection 106.

The water supply pump '86 is'air-operated, operating air being supplied thereto from 'tank '32 through a fitting 110 (Fig. '3) and a line 112 which leads to a double pilot 4-Way reversing valve 114. The latter is operated by air supplied through lines 116, 118 from a 4-way the'valve 114 and its mufllers 126. The valve 120 has a supply-discharge line 150 (best seen in Figs. 4 and 5) connecting with a trigger valve and the pilot operator 104 of valve .102 so that the air for operating reversing valve 114 is supplied by valve 120 under the control of trigger valve 140.

jWater release valve 102 is operated by pilot 104. The latter is air operated in turn by the 4-way, clevis-operated trigger pilot valve 140 mentioned above, which is located on the front end of thespray ring cabinet 11 as is shown in Fig. l. The valve 140 issupplied with high pressure air .from tank 32 by a line 141 connecting at an inlet port 142 located in the middle of the valve, the supply line 141 not beingshown in Figs. .1 to 3, but see Figs. -4 and 5. Lines 146, 148 connect valve .140 with the pilot operator 104, line 146 also connecting with .line

150 which connects the central air supply dischargeport 151 of valve 120 with valve 140. The valve member 152 of valve 140 is pivotally connected through a clevis 153 with a push rod 154. The rod 154 is connected on its other end with either a pin 155 attached to a trigger 156, as shown in Fig. l, or with a mounting pin or shaft 158 of trigger 156, as is shown in Figs. 4 and 5. The trigger is shown inFigs. 2, 4 and 5 to be a section of angle iron pivoted on pins or shafts 158 carried on each side of the aperture 24 by a plate 160 mounted on the front of the cabinet. As appears in Figs. 2 and 4, the trigger 156 is so mounted as normally to have a slight, upward tilt. When a billet or ingot is laid on the trigger, the latter pivots down to the horizontal billetsupporting position, thereby depressing rod 154 and valve element 152 and operating trigger pilot valve 140. The latter opens to supply air through line 148 actuating pilot 104 to open release valve 102. When the billet is removed, the trigger returns to its normal upwardly-tilted position, closing valve 102 and energizing valve 120 through line 150.

Before proceeding with the detailed construction and operation of the valves, the water supply pump 86 will be described'in greater detail. As shown in Fig. 6 the pump comprises a central cylinder portion and two cylinder heads 172. On each cylinder head 172 there is secured a flange plate 174 with a circular sealer element or O-ring 176 being interposed for sealing purposes. Each flange plate 174 has welded in its center an outwardly projecting ram cylinder 178 which is coaxial with cylinder 170. In stufling boxes 180 retained between the cylinder heads 172 and the plates 174 there is mounted a double-ended piston rod 182 which carries a large air or actuating piston 184. Each end 186 of the piston rod 182 constitutes a water delivery ram which forces water out of its cylinder 178 through inlet and outlet passageways 188 bored in the corresponding flange plate 174.

On each end of a plate 190 secured across the cylinder heads 172and flange plates 174 there is mounted a curved rocker arm 192. The lower end of each of the arms 192 make contact with a pin 194 which passes through the flange plate 174 and cylinder head 172 to project into the cylinder 170. When the air piston 184 reaches the end of its stroke it contacts one of the pins 194, forcing it outwardly. Pivotally secured to each of the rocker arms 192 is a spring-loaded push rod 196 which is secured to the valving member 198 of the 4-way double clevis operated valve 120 mounted on the plate 190. Thus, air admitted to the cylinder 170 on one side of piston 184 will move the piston to expel water from the corresponding ram cylinder 178. When the piston 184 bottoms, contacting the pin 194 on that side, the position of' va'lve member 198 of valve 120 is reversed, thereby reversing valve 114. When air is again supplied to the valve 114 through clevis valve 120, valve 114 will supply air to the opposite side of piston 184 causing the latter to reverse.

' Operation With the above general description in mind, reference will nowbe .had to Fig. 4. This view shows the various elements describedabove in a schematic arrangement in which like numerals identify the corresponding elements of Figs. 1 to 3. Because the outer cabinet 10 and the scale trap tank 42 do not appear in Fig. 4, the water tank is shown as a separate element and is identified by the numeral 200. Fig. 4, as was noted above, represents the conditions and positions of the valves before an ingot or billet has been laid on the trigger 156. When the air supply line 34 and water supply line 50 are connected to supply, the pressure in tank 32 builds up to'the desired value and .the water tank 200 fills to the desired level. Let it be assumed that :at the time of connection to supply, the actuating piston 184 of water supply pump 86 was then at .its farthermost right-hand position. The piston 184 will thenvhave actuated the clevis valve 120 to theposition shown in Fig. 4 and reversing valve 114 likewise will have been actuated to the position shown. The piston 184 then begins to move to the left delivering water to the water ram cylinder 68, the outlet check valves 92 and 96 in line 94 then being open. At the same time the right-hand end of the pump is drawing water from tank 200 through lines 80, 84b and check valve 87. As the pump actuating piston 184 continues to move to the left the ram 66 will be raised against the pressure over piston 62. In order to do this the operating ratio of pump actuating piston 184 and its rams 182'will have to be larger than that of actuating piston 62 and ram 66. Assuming, for example, a pump ratio of 30:1, a water ram ratio (ram 66 and piston 62) of 25:1, and an air tank, pressure of 80 p. s. i. gauge, pump 86 will then deliver water at 2400 p. s. i. and ram 66 will deliver water at 2000 p. s. i. When the ram cylinder 68 is filled, piston 62 contacts a stop (not shown) and pump 86 will cease pumping due to a balancing of pressures. While piston 62 is being raised by delivery of water to cylinder 68, the air over piston 62 will be returned to tank 32 through the open line 70. In this way less air is exhausted to atmosphere. In fact, in the apparatus illustrated the only air exhausted to atmosphere is from the pump 86 and the various valves and their lines. This economy of air enables a relatively small plant air supply and small supply lines to maintain effective working pressures in tank 32.

While the pump actuating piston 184 is moving to the left, the valves and their valving members will be as shown in Fig. 4. Air at the left of piston 184 will be exhausting through line 122, port No. 1 of valve 114, and the left-hand muffler 126 attached to valve 114. Meanwhile, high pressure air is being supplied to the right-hand face of piston 184, port No. 2 of valve 114 being opened to'connect lines 112, 124. Valve 114 in turn will have been operated to the position shown by high pressure air entering its right-hand piston chamber 202 from clevis valve 120 through line 118. Valve 120, as indicated above, will have been operated to its position shown by the right-hand rocker arm 192, high pressure air inlet line 150 having been thus connected to line 118 through the valve, as shown.

When the pump actuating piston 184 bottoms at the left it contacts the pin 194 causing the clevis valve 120 to be reversed so as to occupy the position shown in Fig. 5, whereby high pressure air is admitted to the lefthand piston chamber 203 of pilot valve 114 through line 116 causing valve member 201 to be moved to the right admitting high pressure fluid or air tothe left-hand side of the pump actuating piston 184. Piston 184 then moves to the right to expel water from its right-hand ram cylinder 178 and refill the left-hand cylinder 178. If ram cylinder 68 is filled and valve 102 is closed, pump actuating piston 184 cannot move since the pressures are balanced, as indicated above.

When a billet 204 is laid on trigger 156, the latter pivots down causing trigger pilot valve 140 to be reversed to occupy the position shown in Fig. 5. High pressure air is thereby admitted to the bottom side of the piston 205 of the pilot operator valve 104 (through line 148) causing the valve element 206 of valve 102 to move upwardly releasing water through line 106 to the spray ring 22. The latter, as shown, has three spray nozzles 208, preferably having inserts of carbide spaced about its inner periphery so as to cause a triangularly-shaped spray 210 of water at 1500 to 2000p. s. i. to impinge upon the hot surface of the billet. The billet is pushed into the cabinet its full length, in which case the workmans tongs may rest in the trigger to keep the latter in the depressed condition. By visual operation the operator passes the billet in and out as may be required during the water delivery period.

The opening of valve 102 allows piston 62 to begin its downward movement causing the discharge of water from ram cylinder 68. At the same time, should pump 86 have stopped intermediate its stroke, the drop in pressurein line will allow the pump outlet check valves 92, 96 to open causing the piston 184. to complete the remainder of its stroke, delivering its water to the spray ring. Pump 86 will continue to so deliver water duringthe spray period until it bottoms and reverses its clevis valve 120. While trigger 156 is depressed, however, the middle port 151 of the clevis valve is discharged through line 150 and the discharge side of trigger pilot valve 140. Clevis valve 120 then cannot reverse the pump pilot valve 114 and the pump 86 will remain inoperative during the remainder of the spray period. Of course, if pump 86 had been stopped at the end of a stroke, the opening of trigger valve by the billet would de-energize clevis valve 120, the pump 86 would be inoperative and water would be discharged only from the ram cylinder 68. Water will continue to be discharged from cylinder 68 as long as trigger 156 is depressed, until cylinder 68 is empty, at which time the spray automatically ceases. If the billet 204 is withdrawn before cylinder 68 is empty, however, the trigger 156 will move upwardly to resume its normal position moving the valve member 152 of trigger valve 140 upwardly, thereby admitting high pressure air through line 146 to the top side of the piston 205 of the water release pilot valve 104. The valve member 206 of valve 102 then moves downwardly to close the high pressure water release valve 102 and terminate the flow of water. As noted above, pump 86 will then be automatically energized through the energization of valve 120 to refill ram cylinder 68. The operator of the descaling apparatus would normally consume the full spray period in order to thoroughly remove all scale from. the billet or ingot. When this is done the supply pump 86 would usually be shut off with its piston at the end of the stroke. Thus, air normally is drawn from tank 32 during the spray period only by the ram piston 62. By coupling valve 120 to the trigger valve140 in this way so as to de-energize valve 120 during the spraying period, the plant air supply can more easily maintain full operating pressure on air tank 32.

The actuation of trigger valve 140 by the removal of the billet 204 re-energizes clevis valve 120 (by connecting line to line 141, as shown in Fig. 4) valve 120, in turn, reversing the pump reversing valve valve 114 and thereby re-energizing the pump 86. The latter then begins to refill the ram cylinder 68 as before. When the pump actuating piston 184 bottoms, it contacts the corresponding pin 192, reverses the positions of valves 120,

. 114 and continues to deliver water to ram cylinder 68 until the later is filled, at which time pump actuating piston 184- stops its movement. Meanwhile, air continues to accumulate in tank 32 and water to flow into the water supply tank 200 so that the apparatus is always fully charged ready for the insertion of the next billet or ingot.

The descaling apparatus of this invention, just described, is seen to be a small, compact and inexpensive unit of moderate weight having all operating components enclosed in, mounted on or aflixed to a single cabinet. To ready the unit for use, only air and water lines need to be connected. Because of these features the unit is easily moved about the forging shop wherever it may be required. The unit requires no oversize electric motors and, therefore, the unit does not expose plant personnel to high voltage electricity in the steam laden atmosphere usually attendant upon descaling operations. But to its efiicient use of air, a very small air supply system is sufficient for its operation. Because it incorporates a recycle water supply, no sewer connections are required. The latter is a most important feature because sewer lines are most diflicult to maintain under the shock conditions prevalent in a forge shop.

The use of a fairly large air accumulator tank and a water ram enable the apparatus to deliver water at any desired pressure, for example, at 1500 to 2500 p. s. i., with no more than a 10 or 15 drop in pressure over the means :for spraying high pressure water over the surface of the said hot metal, a ram and a ram cylinder for supplying water at said high pressure to said spraying means, said ram being movable between two extreme positions, an actuating piston attached to said ram, an accumulator vessel for maintaining a substantially constant'pre'ssure of a compressible operating fluid on said actuating piston during movement-of said ram between said positions, meansfor supplying water to said ram cylinder at a pressure sufficient to overcome said constant pressure, and

valving means for releasing water from said ram cylinder to saidspraying means.

2. An apparatus for descaling hot metal billets and ingots comprising means for spraying high pressure" water over the surface of said hot metal, a first ram and ram cylinder for supplying water at said high pressure to said spraying'means, an actuating piston attached to said first ram, means for maintaining a substantially constant .pressure of an operating fluid on said first ram actuating piston and including a reservoir of said fluid, ahsecond ram, ram cylinder and actuating piston for supplying water to said first ram cylinder at a pressure suificient to overcome the pressure of said fluid on said first ram actuating piston, means for supplying said second ram actuating piston with operating fluid from said reservoir, first valving means responsive to the introduction :of said hot metal to said apparatus for releasing water from saidfirst ram cylinder to said spraying means, and second valving means responsive to the removal of. said .m'etal from the apparatus for releasing water from said second ram cylinder to said first ram cylinder.

3. The combination according to claim 2, further provided with a third ram and ram cylinder secured to the actuating piston of said second ram and ram cylinderon the opposite side thereof, and means for supplying water toxsaid first ram cylinder alternately from said second and-third ram cylinders.

i 4. The combination according to claim 2, further provided with means responsive to the introduction of said hot-metal' to said apparatus for disenabling said second ram, rarn cylinder and actuating piston.

5. Apparatus for descaling hot metal, comprising a watertightcabinet, an air'tank inside said cabinet, a compartment integral with said cabinet and having an aper- Hire, a spray nozzle ring in said compartment adjacent said aperture and adapted to spray high pressure water over the surface of a piece of said hot metal inserted through said aperture, a first ram and ram cylinder atta'ched to said cabinet, a first connection between said first ram cylinder and said ring whereby said first ram niay deliver water at high pressure to said ring, an actuating piston attached to said first ram, an open passageway connecting said air tank with an operating face of said actuating piston, a second ram, ram cylinder and actuating piston having a larger operating ratio than thatof said first ram, ram cylinder and actuating piston for supplying water to said first ram cylinder, a second conn'ection between an operating face of said second ram actuating piston and said air tank, a trigger adjacent said housing aperture, a first valve in said first connection responsive 'to a first movement of said trigger to release water from said firstram cylinder to said ring, a second valve in:said second connection responsive to a second movement of said trigger to -release'air from said tank to said second ram actuating pistonto expel water from said second ram cylinder to said 'first ram cylinder, a passageway connecting the interior of said spray ring compartment with saidcabinet, a scale trap in ,said passageway, apassageway leading from said cabinet to said second ram cylinder, an air supply connection for said air tank extending from said cabinet, and a water supply connection for said cabinet.

6. An apparatus for descaling hot metal comprising spray means for spraying high pressure water over the surface of said hot metal, a ram and ram-cylinder, a connection between said ram cylinder and said spray means, a valve in said connection movable between an open position permitting said ram cylinder to supply said high pressure water to said spray means and a closed position discontinuing said'supply, an air piston for operating said ram, an air reservoir for supplying air to said piston, an open passageway connecting said reservoir with an operating face of said piston, means for supplying water to said ram at a pressure exceeding that exerted on said ram by said piston, and means responsive to opening of said valve for'rendering said last-named means inefiective.

7. An apparatus for descaling hot metal comprising means for spraying high pressure water over the surface of the said hot metal, a ram and ram cylinder for supplying water at said high pressure to .said spraying means, said ram being movable between two extreme positions, an actuating piston attached to 'said ram, means for maintaining a substantially constant pressure of an operating fluid on said actuating piston during movement of said ram between said positions, a second ram and ram cylinder for suppyling water to said first rarn cylinder, a second actuating piston for said second ram, said second ram, ram cylinder and actuating piston having a higher operating'ratio than that of said first rarn', ram cylinder and actuating piston, means for supplying an operating fluid to said second ram actuating piston at approximately the same pressure as that supplied to said first ram actuating piston, and valving means for releasing water from said ram cylinder to said spraying means.

References Cited in the file of this patent UNITED STATES PATENTS 527,981 Higgins Oct. 23, 1894 686,208 Coyan Nov. 5, 1901 1,635,115 Deutsch July 5, 1927 2,145,540 Ellis Jan. 31, 1939 2,169,703 Mason Aug. 15, 1939 2,254,824 Large Sept. 2, '1941 2,349,150 Falaseoni May 16, 1944 2,357,695 Skowron Sept. 5, 1944 2,394,514 Evans Feb. 5, 1946 2,445,985 Weiner July 27, 1948 2,592,940 Monoyer Apr. 15, 1952 2,614,316 Daily Oct. 21, 1952 2,642,045 Potts June 16, 1953 2,748,036 Deitrickson May 29, 1956 2,790,230 Sobek Apr. 30, 1957 FOREIGN P-ATENTS 54,530 Germany Mar. 18, 1890

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