US1947902A - Piston pump - Google Patents

Description

Feb. 20, 1934. R. DE s'rou'rz PISTON PUMP sis-Sheet 1 d Feb. 12, 1930 at u- 1 2c File 2:3

2+ 15 28 as 2? l 11 Flg. 2.

Patented Feb. 20, 1934 1,947,902 Heron rum Robert de Stunts, Niederbronn, France Application February 12, 1930,

and in Germany Feb Serial No. 427,988, mar: 16, 1929 '1 Claims. (01. 103-162) The present invention relates to a valveless rotary spinning pump adapted especially for delivering viscose in the manufacture of artificial silk.

The piston pumps usually employed in the manufacture of artificial silk consist chiefly of a cylindrical body rotating in a casing and containing the pump cylinders and pistons disposed parallel to its axis of rotation, the body acting simultaneously as distributor or distributing slide valve.

The invention belongs to this group of piston pumps, but differs therefrom in several essential points.

The invention is illustrated by way of example in the accompanying drawings, in which Figure 1 is a longitudinal section of the pump; Fig. 2, another longitudinal section disclosing a difierent piston drive; 3,.a cross section according to line A of Fig. 2 seen from right to left; Fig. 4,.a cross section according to line B of Fig. 2 seen from left to right; Figs. 5 and 6 are, respectively,- longitudinal and cross sections of a modification of the distributing system: Figs. '1 and 8, modifications of the piston drive; and Fig. 9 is a view of the check valve in the pressure piping.

Referring to the drawings, the pump shown in Figs. 1 and 2 is provided with a frame-like casing 1 wherein a cylinder barrel rotates comprising the three parts 2a. 2b and 20. v

In the part 2a the pump cylinders and the pistons 3 are arranged parallel to the. axis of the body, and the parts 2b and 2c serve as'guides for the crossheads 4. L

The casing 1 is clmd by the cover 5 through which passes the driving shaft 2 which is connected with the part 2b. In the flat top of the cover the semicircular suction ducts 6 and the pressure ducts 'l are positioned (Figs. 2 and 3) which alternately come into communication with the various pistons 3 to which sliding motion is imparted by the crossheads or drivers 4 with which they are coupled and which are actuated by the spider- 8 rotating on the pin 9 (Fig. 1), the

pin being, however, in oblique position relative to the casing. In order to effect coupling the crossheads 4 are provided with ball joints which are engaged by the arms of the spider 8 and which permit universal adjustment of the spider relative to the crossheads. In Fig. 1, the pin 9 of the spider 8 is connected with a ball segment 11 disposed in a socket constituting the bottom of the casing. After releasing the nut 13 the spider pin may be inclined at any angle to vary correspondingly the piston stroke and the output of the pump. 7

In Fig. 2, the spider 8 rests on the spherical pin 14 in the pump shaft and, with its shank 15, in a tiltable ball segment similar to the one shown 6 in Fig. 1 and forming the hearing; In either case the was of rotation of the spider coincides with that of the ball segment 11, which is secured to the casing- In Fig. 2 the plain bearing in the ball segment '11 can be replaced by a ball bear- According to 7. and 8, the crosshead joints consist of'the cylindrical parts 16 positioned in bores vertically to the axes of the crossheads. The arms 8 passing through the parts 16 70. are cylindrical to insure universal adjustment of the spider relative to the crossheads. Moreover. in the figures referred to the members 16 are arranged eccentrically to the crosshead axis, a bore providing an opening in the crosshead for the 7l passage of the spider arm.

The pump functions as follows:

The shaft 2 actuated by a gearing (not shown) causes the motion of the cylinder body composed of the parts 2a, 2b and 2c.

The spider'a, the stationary pivot of which is inclined, effects a rectilinear alternative motion of the crossheads and pistons 3. The various cylinders come alternately into communication with the suction duct 6 and the pressure duct '7, the viscose being sucked up from the outside through the ducts 1'7, 18, 19,- and 6 and forced under pressure through the ducts "l, 20, 21, 22 and the crossheads 4 towards the inside of the pump and into the chamber 23. The viscose then passes the groove 24 in the pin 14 and the bore 25 of the spider 8 and, finally behind the bearing of the ball segment 11 whence it passes through the grooves 28 and the chamber 27, and flows through theopenlng 28 toward the annular collector29. It then moves through the duct 30 milled into the casing and along the cylinder body and comes out of the pump through the duct 31.

In the known typesof pumps the liquid is usual- 1y controlled by semicircular suction and pressure ducts arranged in the wall of the casing and getting alternately into communication with the cylinders during the rotation of the cylinder body by means of openings provided in the said body.

Packing between the suction and pressure ducts is efiected by fitting the cylinder body tightly into the casing, and this extremely accurate fitting which leaves hardly any play is responsible-for the difllcult running or gumming up of the pump, i. e., the resistance acting against the rotation of the shaft is considerable and involves a corresponding consumption of power.

If the rotary speed is increased beyond a certain limit for spinning large filaments, heat and corrosion are developed. After a certain length of time and owing to the wearing down of the cylinder body and casing, which can not be compensated by any kind of adjustment, losses will be noted and the output decreases.

Pumps are known, in which control takes place between the fiat end of the cylinderbody and the cover of the casing by means of suction and pressure ducts arranged in the cover. In pumps of this type packing is effected by the regulation of a screw or the'like permitting regulation of the play between the cylinder body and the cover. However, such a method of regulation is extraordinarily sensitive.

In the pump according to the present invention, these defects, unlikev the means employed in all existing kinds of pumps, are eliminated by forcing the viscose sucked up through the suction duct 6 under pressure through the cylinder body and between the latter and the bottom of the casing into the chamber 27 with the result that the cylinder body is pressed automatically with its.

flat end against the cover 5 of the casing, wherein the suction and pressure ducts are arranged. In this way absolute and invariable packing of the means of control is attained in a perfectly automatic manner and without the slightest adjustment. Moreover, as the casing is not used any more for control, the play between it and the cylinder body may be increasedin order to reduce the power required.

It is suiiicient to position only the suction duct 6 in the flat cover surface, and the pressure duct 7 can be arranged in the wall of the casing, as indicated in Figs. 5 and 6. The aim is to effect packing of the controlling surfaces by the pressure of the viscose inside the pump. i. e., to separate the cylinders engaged in the suction stroke from those negotiating the pressure stroke and, on the other hand, the suction duct from the pressure duct. This end is attained even if the suction duct only is disposed in the cover, and an alteration of this kind does not constitute a deviation from the essence of the invention.

By passing the viscose under pressure through the entire inside of the pump and by putting the inside under pressure another'advantage is gained not found in the known types of pumps, namely, the prevention of t e entrance of air. It is a matter of record tha the pump might aspire indeed under atmospheric pressure, in which case air will unavoidably enter. However, if the inside of the pump is put under over-pressure, this drawback is eliminated completely.

It is of utmost importance in viscose pumps that obstructions in the flow of viscose be prevented, that is, there should be no places where the viscose is not continually renewed, no matter how small they may be, because at suchpoints the viscose will harden remarkably quickly. For this reason provision has been made in the pump according to the present invention that the viscose is forced through the crossheads owing to a special arrangement of thepressure ducts. In Figs. 2 and 3 the ducts 22represent openings which alternately brin each crosshead into communication with the duct 21 (Fig. 3) so that, at each rotation of the pump,-theviscose is forced to pass during a certain period through the crosshead, whereby the hardening 0! viscose in the latter is prevented.

On the other hand, hardening of viscose in the annular collector 29 is prevented by guiding the viscose from the chamber 2'7 to the collector through asmall opening 28 in the rotating cylinder body, which covers the entire circumferenc of the collector 29 during rotation.

Another feature of the invention is the complete elimination of all transverse forces acting on the pistons and favoring wear of the cylinders.

The conversion of a rotary motion into a rectilinear sliding motion is practically impossible without producing transverse forces directed vertically to the sliding motion.

According to the invention, the component forces due to the inclination of the spider do not act directly on the pistons as in the known pumps of this class, but on the crossheads 4'at' the end of the pistons 3, the crossheads being connected with the pistons so that transverse forces cannot act on the pistons. To this effect the pistons are provided with heads, which enter outmillings in the crossheads. Said outmillings extend on one side to the crosshead circumference and they are somewhat larger in diameter than the piston heads in such a way that some play is left on 100 the connecting spots.

For this purpose, the bayonet-like piston ends have a certain amount of play in their crossheads. whereby transverse pressure on the pistons and thus the wear of the latter in the cylinders are 105 prevented.

A further distinguishing feature of the inven- I tion is that a single star-like member rotating about a pin secured to the casing causes the stroke of the pistons by means of arms engaging joints 110 on the pistons or their crossheads in such a way that the crossheads are guided in the cylinder body at both sides of the star or spider, unlike the known pumps wherein the pistons are en- ,%aged at the end of the cylinder body and the 118 pistons. In this way the length over all of the pump is reduced as well as the unsupported carrying on the pistons and their crossheads.

After removing the part 20 of the cylinder body the spider can be introduced and, according 12 to Fig. 2, packing of the spherical hub of the spider is maintained relative to the part 20, which makes it possible to force the viscose through the groove 24, the bore 25 and the bearing and into the ball segment 11. 12

A ump constructed according to the invention difl'ers further from the known types in so far as the part of the cylinder body containing the pistons is inde endent from the one comprising the drivin shaft and the crossheads. which permits the surface grindin oi' the part 212 without interference by the driving shaft.

It mi ht be of interest in certain cases to increase the viscose pressure within the pump, which can be achieved by inter-nosing between the um and the spinning nozzle a check valve of the tyne sho n. for example, in Fig. 9 or by arran in it within the ump. Or the duct 31 ma be blocked bv a ball 32 influenced by the spring 33, the spring 34 serving for adjusting the. tension of the spring.

The annular duct 18 in Fig. 2. which surrounds the driving shaft 2, is passed through by the viscose when sucked up and serves for catching the viscose under pressure, which might escape from the inside of the pump between the shaft and its bearing. This duct maybe dispensed with, however.

I claim:-- 5

1. In a valveless rotary spinning pump, hav- 1 ing a casing, a cover on the casing, a rotary cylinder block, pistons reciprocating therein and means for driving the pistons, axially guided crossheads positively connected to said pistons,

and a connecting means for the pistons and crossheads comprising a head on the piston, a narrowed stem between the head and the piston, a hollow and a passage in the crosshead engaged by the piston, head and the stem, the piston head being of smaller diameter than the hollow but larger than the passage in the cross-' head, whereby the crosshead will drive the piston without axial play and will move freely in universal radial direction to the piston, thus avoiding transverse pressure to be imparted by said crosshead to said piston.

2. In a valveless rotary spinning pump as claimed in claim 1 having a driving shaft with a ball at its inner end, a ball cup forming the hub of a spider and cylindrical spider arms on the spider, peripheral grooves in the ball, a tightening abutment for the ball cup, a hollow shaft on the ball cup extending through an opening in the cylinder block into the adjustable guiding segment and grooves in the segment bore surrounding said shaft.

3. In a valveless rotary spinning pump as claimed in claim 1, a cylinder block consisting of two parts. circular guide bores for the cross-.

heads in each part and the spider placed between both parts.

4. In a valveless rotary spinning pump as claimed in claim 1, ducts in the crossheads for forcing the liquid through them.

5. In a valveless rotary spinning pump as claimed in claim 1 in combination with a spider having cylindrical spider arms, transverse bores eccentrically located in the crossheads. cylindrical links in said bores, cylindrical bores in the links for engaging the cylindrical spider arms.

6. In a valveless rotary spinning pump having a casing, a cover on the casing, a rotary cylinder block with a flat base, pistons reciprocating therein, means for driving the pistons, a corresponding flat surface on the casing cover and a distributing means in said cover a duct in the casing wall leading from the compression groove of the distributing means to openings in the flank wall of the cylinder block, a chamber in the cylinder block in connection with said openings, channels for the fluid passage in the piston driving means, a gap in the border of the cylinder block, an annular groove in the casing wall communicating with said gap and a duct in the casing leading from said annular groove to the discharge port.

7. In a valveless rotary spinning pump as claimed in claim 1 in combination with a distributing means comprising fiat surfaces in contact with one another, a duct in the casing wall leading from the compression groove of the distributing means to openings in the flank wall of the cylinder block, achamber in the cylinder block in connection with said openings, channels for the fluid passage in the piston driving means. a gap in the border of the cylinder block, an annular groove in the casing wall communicating with said gap and a duct in the casing leading from said annular groove to the discharge port.

ROBERT ns STOUTZ.

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