US1952994A - Pump and cushioning device therefor - Google Patents

Description

Patented Mar. 27, 1934 UNITED STATES PATENT OFFICE 2 Claims.

My invention relates to new and useful improvements in metering pumps for the pumping of viscose, nitrocellulous collodion, acetate, cuprammonium, or other similar fluids used in the manufacture of rayon, artificial straw, and other goods having the same base as rayon.

Still another object of the invention is to provide a cushioning device and known in the trade as a pressure bottle with the pump to obtain a cushioning effect to absorb the pulsations al- Ways presented when a piston pump is used.

Y Still another object of the invention is to provide a new and novel form of cushioning device to absorb or cushion the pulsations that are common in the various forms of pumps, the present device being especially adapted for use with the types of pumps shown in Patents Nos. 1,783,439, on Pumping unit for artificial silk spinning machines, granted December 2, 1930, 1,785,355, on 20 l Spinning pump, granted December 16, 1930, and 1,785,356, on Spinning pump, granted December 16, 1930.

Still another object of the invention is to provide a relatively non-breakable cushioning device known in the trade as a bottle in which there is either a fixed diaphragm or a floating means that is compressible so as to absorb or cushion the pulsations of the pump to thus produce a steady flow of the liquid from the pump to 30 the spinneret or spinning jet.

It has been the former practice with a pump of the type shown in the above-mentioned patents to provide a glass cushioning device that is tightly but detachabl'y held over an inlet and an outlet, so that the liquid passes from a port up into this cushioning device, where the pulsations are absorbed or cushioned by the air in the cushioning device before the liquid passes to the spinneret and is solidified into a thread.

Still another object of the invention, therefore, is to provide a cushioning device that is preferably made of metal, but mightbe made of bakelite, hard rubber, or similar substances.

Still another object of the invention is to provide a pump with 'a cushioning device which is preferably made of metal and in which there is located a diaphragm behind which the air is entrapped, so that when pressure is built up in the cushioning device, the diaphragm and even the air behind it will be compressed to thus absorb and cushion the pulsations of the, liquid flowing into the cushioning device and thus cause the liquid to be delivered in a steady stream from the outlet port of the cushioning device to the spinneret.

Still another object of the invention is to provide a pump with a cushioning device wherein a floating form of diaphragm might be used, such as a ball made of relatively thin metal, celluloid, etc. so that the pressure in the bottle will cause the ball to compress and again expand as the back pressure in the cushioning device is equalized to similarly allow a steady jet or fiow from the pump. With these and other objects in view, the invention consists in certain new and novel arrangements and combination of parts, as will be hereinafter more fully described and pointed out in the claims.

In the drawing,

Fig. 1 is a transverse sectional view of a wellknown type of metering pump with the new form of cushioning device attached;

Fig. 2 shows the separate parts of the cushioning device before being assembled;

Fig. 3 is a central sectional view of the pump to show the arrangement of the ports;

Fig. 4 shows a slightly modified form of cushioning device.

Referring now to the drawing, it will be seen that Fig. 1 shows a metering pump of the type shown in Patents Nos. 1,783,439, on Pumping unit for artificial silk spinning machines, granted December 2, 1930, 1,785,355, on Spinning pump, granted December 16, 1930, and 1,785,356, on Spinning pump, granted December 16, 1930, consisting of the cylinder-1, the rotor 2 with the bores 2', in which are mounted the piston plungers 3, which plungers, in turn, are provided with the balls 4 on their ends, which balls fit in chambers 5 in the angularly placed rotor cam 6. This rotor cam 6 bears against the stationary cam face 7 of the back piece 8. On the opposite end of the rotor is the stem 9 extending through the head 10, while on the outer end of the stem 9 is the gear 11. The rotor has a central bore 12 in which is fitted a spring 13, which spring, in turn, bears against the head 14 of the stem 15 which, in turn, bears against the ball 16, which ball is centrally located in a depression 17 in the rotor cam 6. There may be seen the main inlet port 18 which communicates with a circumferential groove 19 formed in the casing. This groove 19, in turn, communicates at times with the cylinders 2 through the ports 2 During the suction stroke of the pistons, therefore, the fluid is drawn into the cylinders 2' through the ports 2 and as the rotor revolves, the liquid is then, by the compression stroke of the pistons, forced over into a secondcircumferential groove 19' through the rotor. From this second circumferential groove, the liquid is forced up through the opening 22 formed in the top of the casing (over which is fitted a pressure bottle, shortly to be described) Another opening 23 may be seen at the top of the casing, in which is fitted the small tube 24, this tube and opening communicating with a further circumferential groove 23, which communicates with the main outlet of the pump 21.

As far as the specification has proceeded, the pump is identical with the pump shown in the above-mentioned patents, with the exception that the little tube 24 is placed in the opening 23 (which in this case is the outlet) rather than in the opening 22, as shown in the patents abovementioned.

The arrangement and description of the grooves and the ports, as well as the glass type of cushioning device, or as known in the trade as pressure bottle, are specifically pointed. out in one of the above-mentioned patents, to wit: 1,783,439, on Pumping unit for artificial silk spinning machines, granted December 2, 1.930, and it is not thought necessary in this application to go into a full discussion of the pump per se.

. It is necessary to have what is known in the trade as a (pressure bottle, asin the pumping of viscose, nitrocellulous collodion, etc., the uniformity of the thread depends entirely upon the uniformity of the delivery of the metering pump and it is, therefore, essential that a cushioning device, known in the trade as a pressure bottle," be used to absorb the pulsations caused by the pistons of the pump.

It will be understood that, the liquid flows up into the pressure bottle and thence out through the outlet to a spinneret or spinning jet (not shown) which is, in reality, a small die with a quantity of minute holes therein and which is submerged in a precipitated bath of different chemicals used to coagulate the liquid into a solid thread, Since the liquid being pumped is usually of a high viscosity, a back pressure of varying degrees is built up when its free passage is obstructed by the aforementioned spinning jet. This back pressure causes the surface of the liquid in the cushioning device to rise until the entrapped air is compressed to a pressure equal to the back pressure caused by the spinning jet. The impulses caused by the separate plungers cause definite fluctuations in the discharge pressure and the air which is entrapped under pressure in the top of the cushioning device acts as a cushion and absorbs the pulsations in such a way that they do not pass on with the fiow of liquid to the spinning jet.

Now heretofore, the so-called bottles were formed of glass and as the liquids cannot be in contact with air for any great length of time without beginning to solidify, that part of the liquid which was in direct contact with the air in the top of the bottle and which does not have as complete a circulation as that in the bottom of the bottle starts to change into a semi-solid mass, making it necessary to remove the bottles from the pump at frequent intervals to remove the mass and to clean out any of the stagnant or partly solidified fluid.

Thus, when the pumps are used by the thousands, there is a relatively large loss of time in the removal and cleaning of the bottles. Furthermore, the bottles when made of glass were often broken, due to' carelessnesson the part of further aligning ports 2 that are formed in the" operators, back pressure in the bottles, and im'- perfect bottles.

Now referring to the gist of the invention, there will be seen what is known as a pressure bottle 25 that is a cushioning device, and in the present instance it is preferably formed of metal, although a cushioning device formed of hard rubber or bakelite might be used. It will be noticed that this cushioning device 25 is threaded at its lower end, as at 26, to removably fit within the threaded portion 27 of the lug 7 Resting on top of the cushioning device 25 or fitted therein is the compressible tempered convex steel diaphragm 28, while over this, in turn, is tightly screwed the cover 29. It will be noticed that there is an air space 30 provided between the diaphragm 28 and the top of the cover 29.

In the present instance and, as shown in Fig. 1, rather than entrapping the air in the cushioning device, the inlet and outlet ports have been changed from the pump shown in the previous patents and thetube 24 is placed in the outlet port instead of the inlet port to thus expel the air rather than trap it.

The impulses then, instead of being absorbed 100 by the air cushion, as in the former style, are absorbed by the tempered steel diaphragm 28 and further by the air cushion 30 behind the steel diaphragm. In other words, when the cushioning device has become completely filledwith the liquid 105 (not shown) the back pressure forces the concave tempered steel diaphragm to rise until its resistance is equal to the back pressure caused by the liquid being retarded in the spinneret or spinning jet. Thus, as the pulsations occur in the delivery of the liquid to the cushioning device, the diaphragm will rise and fall at each impulse to cause a cushioning effect. There is alsoan added cushioning efiect, however, due to the air en trapped behindthediaphragm or inthe ball, so that the pulsations are really absorbed or cushe, ioned by both the diaphragm and the air that is compressed behind the diaphragm, or in the ball, ifthe modified form is used.

In Fig. 4, I have shown a cushioning device 31 120 with its cover 32, but rather than having a fixed diaphragm therein, there is placed a compressible sealed ball33, that mi ht be made of tempered steel or other thin metal or, infact, might be made of relatively thick celluloid, rubber, fiber, or any other composition that will allow the sides or surface of the ball to be compressed by the fluctuating pressure in thecushioning device to thus absorb the pulsations.

From the foregoin it will be seen that by forming a cushioning device of metal with a. compressible diaphragm therein, I have dispensed with the ordinary glass bottle, thus overcom,-. ing what amounts to a serious loss of time caused by the breakage of the bottles, andfurthermore, have provided a cushion n device that will not neednearthe cleaningthat the glass bottle, does. Again, rather than entrapping the air, the air is expelled from the cushioning device, while the pulsations of the liquid in the cushion 140 ing device are absorbed or cushioned by the diaphragm and the cushion effect furtherassisted by the air. entrapped behind the diaphragm.

In actual use, I have found that the cushioning device remains clean and thatthe discharge of the viscose from the cushioning device is in a fine and even stream, free of pulsations, which results in a uniformity of delivery to thus cause a uniform thread.-

It will be understood that this cushioning do, 150

vice might be readily adapted for use with other forms of pump besides that shown, as it may be easily fitted by simply cutting a receiving thread in the casing over openings that are present in any form of pump, where the glass type cushioning device is used.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:-

1. In combination with a rotary reciprocating type metering pump, the casing of the pump provided with an inlet, a port connected with the inlet and pistons cooperating with said port to force the fluid under pressure into a cushioning device, said cushioning device including an air chamber having a flexible diaphragm therein, the pump also provided with an outlet port, a pipe within the cushioning device, its upper end adjacent said flexible diaphragm and connected at its lower end to said outlet port whereby fluid under pressure will pass from said cushioning device and pump in a steady stream rather than with a pulsating efiect.

2. In combination with a rotary reciprocating type metering pump, the casing of the pump provided with an inlet, a port connected with the inlet and pistons cooperating with the port to drive the liquid through said port, a cushioning device, said cushioning device including an air chamber having a flexible diaphragm therein, a pipe within the cushioning device its upper end adjacent said flexible diaphragm, the fluid under pressure being driven through said port and into said cushioning device, the lower end of the pipe of the cushioning device constituting an outlet from the cushioning device whereby the fluid under pressure will pass from the pump into the cushioning device and then from said cushioning device in a steady stream rather than with a pulsating effect.

JOSEPH PAUL LAIRD.

Images