US1982770A

US1982770A - Constant volume pump

Info

Publication number: US1982770A
Application number: US378823A
Authority: US
Inventors: Paul L Tollison
Original assignee: Wood Newspaper Machinery Corp
Current assignee: Wood Newspaper Machinery Corp
Priority date: 1929-07-17
Filing date: 1929-07-17
Publication date: 1934-12-04
Anticipated expiration: 1951-12-04

Description

Dec. 4, 1934. p o so 1,982,770

CONSTANT VOLUME PUMP Filed July 17', 1929 4 Sheets-Sheet 1 Wrm... fwd??? 1M Dec. 4, 1934. P. L. TOLLISON CONSTANT VOLUME PUMP Filed July 17, 1929 4 Sheets-Sheet 2 dezzv w m a A 2 mi J 5 2 w A m 4.7 a a .5 4*

1934. P. L. TOLLISON CONSTANT VOLUME PUMP 4 sheets-sheet 3 Filed July 17, 1929 I Dec. 4, 1934. p ITOLLISON 1,982,770

CONSTANT VOLUME PUMP Filed July 17, 1929 4 Sheets-Sheet 4 .Zr/ezr Q wrmyr Patented Dec. 4, 1934 UNITED STATES PATENT orrlca 1,982,770 CONSTANT VOLUME PUMP Application July 17, 1929, Serial No. 378,823

zOlaims.

This invention relates to the provision of a piston pump with means whereby the same volume of liquid will be pumped at every stroke regardless of the level of liquid in the pump or melting pot or of other disturbing influences.

The chief object of the invention is to provide simple and effective means for measuring out a certain predetermined volume of liquid before the liquid begins to be delivered out of the spout; to provide simple means whereby the pump will have a capacity for delivering more liquid than required and the surplus will spill out at or above the highest liquid level and the port or ports will be closed at that time, thus trapping in the pump exactly the right amount of liquid, no matter what the liquid level is and irrespective of any faults in the valve action or other features of the pump. This invention is not limited to any particular type of pump or to the pumping of any particular liquid but it is particularly adapted for pumping molten metal to stereotype casting machines.

Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompanying drawings in which Figure 1 is a sectional view of a well-known type of pump with a preferred embodiment of this invention applied thereto; I

Fig. 2 is a plan of the same;

Fig. 3 is a view similar to Fig. 1 showing the invention applied to another type of pump;

Fig. 4 is a horizontal sectional view on the line 4-4 of Fig. 3;

Fig. 5 is a view similar to Fig. 1 showing the application of the invention to another form of p p;

Fig. 6 is a horizontal sectional view on the line 6-6 of Fig. 5;

Fig. 7 is an elevation of the means for turning and operating the valve;

Fig. 8 is a horizontal sectional view on the line 8-8 of Fig. 5, showing the valve operating means in plan;

Fig. 9 is a. view similar to Fig. 1 showing another modification;

Fig. 10 is a sectional view on the line 10-10 of Fig. 9, showing the spout in plan, and

Fig. 11 is a sectional view on the line 1111 of Fig. 9, showing the valve operating means in plan.

In the operation of a piston pump, especially in stereotyping, it is desirable that the same volume of liquid be pumped in the same length of stroke regardless of the level of liquid in the pot or pump, erratic valve action, or other disturbing influences. This invention is based on the idea of providing for automatically discharging from the pump, while the piston is operating, all except a predetermined volume of liquid so that the same amount will be discharged from the pump on each c\omplete operation of the piston.

It very often happens that the liquid level in the pump is not maintained and in fact it varies with every pumping operation, because there is no means for restoring to the pump the exact amount of metal pumped each time the pump operates.

It is customary to provide an adjustment between the pump and its prime mover for increasing or decreasing the volume of metal pumped. This adjustment, however, is manually operated and requires constant attention from the operator in correcting for the amount of metal discharged each time and the metal put into the pump to sustain the level. By this invention these difilculties are avoided and the pumping necessarily discharges the same amount at each operation, no

manner what the level of the liquid may be.

In the first two figures I have shown a pump of well-known construction for stereotyping purso poses, with this invention applied to it. This pump islocated in an open topped melting pot or receptacle 10 and comprises a cylinder .11 and piston 12. In the cylinder near the bottom are ports 13 through which the cylinder is filled with molten metal from the pot. The metal enters and stands in the pump, at the same level as in the pot outside.

The piston is provided with a rod 14 operated from a shaft 15 by an arm 16 thereon. This shaft is oscillated in any desired way to raise and lower the piston. Arm 18 provided with abutment 19 opening and controlling closure of valve 21 is adjustably secured to arm 16 by bolt 17. This allows relative adjustment between arm 18 and arm 16 so that the operation of valve 21 may be regulated as desired.

The body of the cylinder 11 is provided with a discharge port 20 at a certain desired level. This port is adapted to be closed by a valve 21 having a spring 22 on its stem for normally tending to keep it closed. This stem is guided in an arm 23 and projects up through it into contact with the bottom of the abutment 19. When the arm 16 comes down, the abutment 19 comes down with it 105 and opens the valve 21 as shown.

By the raising of the arm 16 and piston 12 the first effect is to close the ports 13 and thus provide a confined body of metal in the cylinder and adjacent parts up to the level of the metal in the 1 0' pot at that instant. The further raising of the piston forces the metal up in the delivery spout and in the measuring tower 26 at the top of which is located the port 20. As soon as the metal reaches the level of the port 20, with the valve 21 open, the surplus metal will flow out through this port and the passage 27 back into the melting. pot. The parts are so adjusted or designed that the valve 21' will be closed by the'spring 22 when the abutment 19 reaches. a certain predetermined level and when the amount of liquid in the cylinder is just suflicient to cause the rest of the rise of the piston 12 to force enough metal out the spout 25 to form a complete casting without surplus.

It will be seen that no matter whether the level of the liquid in the melting pot is high or low, so long as there is enough to provide a mold full of metal in the cylinder 11 above the piston}.

the mold will be just fllled at each complete operation of the piston and there will be complete uniformity in the castings produced'as far as the amount of metal is concerned.

When it is desired to operate the pump without discharging metal from the spout 25 a by-pass valve 28 is opened and it discharges into the melting pot. The pump can be tested in this way or foreign particles in the cylinder can be gotten rid of so as to float on the top of the molten metal in the melting pot outside. The above description shows completely how this invention can be employed in a practical and simple way to measure the metal or other liquid discharged by the pump and keep the volume constant for each pumping operation.

There are several other ways in which the invention can be carried out and inFigs. 3 and 4 it is shown as being applied to a type of pump employing a hollow cylindrical valve 30 for closing the measuring ports 31. This valve is secured to the piston rod and when the piston rises to a certain elevation the valve will close ,the ports and entrap in the interior the same amount of metal every time it operates. In this-type of pump the metal is introduced through a port 32 controlled by a float valve 33 as is well known in this art.

In Figs. 5, 6, 7 and 8 I have shown the invention as applied to another type of pump wherein the measuring ports 35 are closed and opened by a piston valve 36 having slotted ports 37 and operated by an oscillating or rotary motion. In this case the valve does not rise and fall but is mounted on a stem 38 on the top of which is located a cam 39 which in turn is operated by a reciprocating collar 40 on the: piston rod 14. This collar has a radial projection 41 entering the cam slot 42 in the cam 39 and consequently turning the valve 36 as the piston rises. This can be timed as well as the others and has exactly the same efiect. I have shown a stufllng box 43 for the valve stem 38.

In the last sheet of drawings Figs. 9, 10 and 11 is shown a construction which combines the conplished by the use of a hollow cylindrical'valve 45 having slots or ports 46 and 58. It is located at the top of a measuring tower 47 and is connected by a swivel Joint 48 and pivoted link 49 to the pump arm 16., when the valve is in the position shown, the. top of the measuring tower isopen and ithas come into that position'i'n proper time so that the desired amount of metal will overflow through the port from the parts below, as in the other case, so that the rest ofthe upward stroke of the piston 12 will just fill the mold.

By operating a link 50 connected to an arm 51 on the valve the oblong slot 56 can be turned to register with the top of the tower 47. Then the pump can be tested and all the surplus metal pours out through this port and through the center of the measuring valve and it acts as a by-pass valve. In this way the single valve performs two very important functions. The link 50 is manipulated by the operator in accordance with his desire to cast or not cast metal in the mold.

The four forms of the invention illustrated indicate the broad nature of the invention and its application to several types of pumps. They are all capable of providing the necessary amount of metal and disposing of the surplus so that each action of the piston will force enough metal out of the spout to fill themold or enough of any liquid to perform whatever function is desired. At the same time the mechanism is simple and the operation can beentirely automatic as has been shown.

Although I have illustrated and described only four forms of the invention, I am aware of the fact that other modifications can be made therein by any person skilled in the art, without departing from the scope of the invention asexpressed in the claims. Therefore, I do not wish' to be limited in this respect but what I do claim is:-

I. In a pump, the combination with a cylinder, a piston therein, a spout for delivering liquid from' the cylinder, an arm for reciprocating the piston, a measuring well extending up from the cylinder and an oscillatory cylindrical valve constituting means for controlling the discharge of metal from the top of said measuring well, of means for operating said arm for raising and lowering the piston and means operated by the motion of the piston for reciprocating said valve, to control the quantity of liquid delivered, said valve being man-