US2186253A - Milking machine pulsator - Google Patents

Description

Jan. 9, 1940. K. G. MAGNI 2,186,253

MILKING MACHINE PULSATOR Filed Aug. 3, 1956 2 Sheets-Sheet l Jan- 9, 1940- K.I G. MAGNI 2,186,253

' MrLxING MACHINE PULsATR l Filed Aug. 3, 1936 2 Sheets-Sheet 2 Patented Jan. 9, 1940 Y uw 'nume' moms rULsA'roa PATENT ori-lcs mamar Magni, nella. noname, sweden, asslgnor to De Laval Separator Company, New York, N.v Y., a corporation of New Jersey Application .iugm s, 1936, serial No. l93,9132

f In sweden August 14, 1935 21 Claims. (Cl. 31-61) My invention is an improvement upon the pulsator of the Forsberg Patent No. 2,042,300, dated May 26, 1936. In this patented pulsator the rate of pulsation is regulated by a iiuid,

preferably air, owing back and forth between 4two closed containers, one at least of which is placed in a pulsator chamber which communicates with the pulsating pressure generated by the pulsator, whereby at least the one container, by its variations of volume caused by the variations of pressure, acts on the members which regulate the distribution of higher and lower pressure. The said containers-at least o'ne of them-must thus be expandable and are advantageously in the form of bellows actingv on the valve mechanism which vregulates the distribution of the pressures. Fig. 4 ofthe said patent shows an embodiment of the invention in which a valve spindle 55, provided with valves 53 and 54, is iniluenced at both ends by bellows 65 and 66. The present invention relates to a modiiication and further development of the pulsator according to Fig. 4 of said patent.

In the pulsator construction shown in Fig. 4

of said patent the valve 54 must be in the position illustrated to make a tight joint against the action of the atmospheric air. Its exact position in closed state, however, is determined by the position of the valve 53, which, in the illustrated position, is kept in contact with its seat by the diierence of pressure between the atmospheric pressure and the vacuum in chamber 62. While such a construction is operative, the distance between the seating faces of the valves must correspond accurately with the distance between the valve seats, and this involves nicely measured accurate construction with some danger even then of failing to obtain the desirable positive sealing between one or the other valve andits seat. One object of the invention is to obtain this positive sealing and to do so even though the parts may not be constructed with the degree of precision required in the prior construction.

Another feature of the prior construction is the provision of sealing collars like those numbered 11 and 18. Experience has shown that there is some danger that the valve system may be locked by these sealing members, particularly when milk enters the pulsator. In any case these sealing members create undesirable forces acting on the spindle.4 Another object of the present invention is 'to dispense with sealing members of` this character.

It is desirable, as k.recognized il; S91@ prior patent, that the total quantity of the air enclosed in the containers should be kept approximately constant. The maintenance of this condition by mechanical means has' not proved entirely satisfactory. Another object of the pres- 5 ent invention is to provide -a more satisfactory and reliable substitute. p

The presentinvention attains the foregoing objects. f

Further advantagesare attained as compared 10 with known pulsators. Thus, in my improvement, each valve in its closed position is kept on its seat under the inuence of the difference of pressure acting on the valve, so that a reliably tight joint is obtained independent of l great accuracy of measuring and independent of the wear of the valves and the seats.

The valves according to the present invention can also easily be made in such a manner that a free passage from the side of the atmospheric pressure` tothe vacuum side is not formed during the moment of reversing, which is the case with all known pulsators without a slide.

Further, it is possible, in accordance with the present invention, to make the valve housing in one piece, which effects a considerable simpliiication of the construction. y

A further defect in known pulsators is that, in a certain intermediate position-which may occur when the pulsator is not in operationit fails to start. In a pulsator embodying the present invention, an operative starting position is insured.

Finally, the bellows according to the present 35 invention are so made that they can be xed to their volume when the pulsator is at rest, by mechanical means, independent of the changes of tension which may, in the course of time, take place in the highly elastic material (for instance rubber) of the bellows. The invention thus embodies a suitable xing device for the bellows in their state of rest;r that is, means to maintain the valve system in a xed and predetermined position, suitable for starting the pulsator, when it is not in operation. l

In the present invention, the chamber Whose volume can be changed and which contains the quantity of air closed to theatmosphere, is not 50 formed by the bellows, as in the ,said prior patent, but by the space` between the bellows and a rigid housing provided around it. By thisy modification certain practical advantages are attained in regard to said fixing device.

The accompanyingI drawings show different embodiments of my invention.

Fig..1`is an end view ofthe pulsator. Fig. v2 is a longitudinal section through the 5 pulsator on the line 2-2 of Fig. 1, the valve spindle being shown shifted to the left.

Fig. 3 is a longitudinal` section through part of the length of the pulsator, on vthe line 3-3 "/foi' Fig. 1; the valves being shown in diagram.

Fig. 4 is an enlarged view of part o1' Fig. 2,

showing the specific 'construction of the valves, the valve spindle being shown in the position it occupies a little before it completes its shift to the left.

Figs. 5 and 6 are longitudinal sectional views, similar to Fig. 4, of modications of one of the valves. I

Fig. '1 is another enlargement of part of Fig. 2, showing more clearly the bellows construction.

Fig. 8 is a view looking from the inside offone oi' the bellows toward its end piece.

Fig. 9 is an enlarged sectional view of a modifled throttling device.

Fig. 10 is a detail sectional view of a modiiied connection between the end air chambers.

Fig. 11vis a fragmentary sectional view of part of Fig. 4 showing a transitory position of valve I4 in the operation of assembling the valves of Fig. 4.

80 Fig. 12 is a detail view of one of the end pieces of the bellows before it is applied to the housing.

The pulsator comprises a casing a having passages connecting respectively with sources of high and low iluid pressure (conveniently atmosphere and partial vacuum), other passages connected with two pairs of teat cups, a valve chamber, valve mechanism reciprocable therein, and pulsation chambers adapted, in the reciprocation of the valve mechanism, to connect different sets of teat cups simultaneously with the high and low pressure passages respectively and to connect each set of teat cups alternately with 4the high and low pressure passages: as hereinafter described in detail.

The chamber I always communicates with the atmosphere through a strainer 2 and a channel 3. The chamber I is provided with a double seatl ing valve 4 mounted on a spindle 5. Gn each side 01' the chamber I there is one of two pulsation chambers 6 and 1, into which the valve 4 alternately admits atmospheric air. The pulsation chamber 1 isA separated from another pulsation chamber 8 by a sealing device 9. Beyond the pulsation chamber 8, reckoned in the axial direction of the spindle, is a chamber IU which always communicates with the vacuum pipe of the system by a channel II and a nipple I2. Beyond the vacuum chamber `Ill there is another pulsation chamber I3. The four pulsation chambers communicate with each other by pairs, as shown in Fig. 3; that is, chamber 8, through channels hereinafter described, communicates with charnber 6, and chamber 1, through similar channels,

with chamber I3. The chamber 6 in turn communicates with two teat cum, and the chamber I3 with two other teat cups. `The pulsation chambers 8 and I3 enclose valves I4 and I5, respectively, carried on the spindle 5, the said valves opening and closing the communication between the pulsation chambers and the vacuum chamber I6.

At opposite ends of the valve system described are bellows I6 and Il, the interiors I8 and I9 of which communicate with the pulsation chambers! and Il respectively. '111e bellows are eiiclosed in chambers 2li and 2I respectively, which are closed to the atmosphere but communicate with each other by a channel 22, in which vare arranged a series o1' throttling devices comprising 5 partitions provided with iine holes 23, which can be made accessible to cleaning by removing a screw plug 24, which is. provided with packing means 240.

The chambers 20 and 2| are closed to the atl0 mosphere by end closures or hoods 25 and 26, which are tightly connected to the pulsator'housing 28 by threads and packings 2l.v

As an alternative the channel 22 can be replaced by a straight channel 29 shown in Fig. 10 l5 and located entirely inside the inner radius of the hoods 25 and 26. The screw 24 with its sealing disc can then be dispensed with, as the throttling holes 23 become accessible for cleaning by a needle or the like'by removing one of the hoods 2 25 or 26 and possibly also one of the bellows. If it is desired to make the throttling openings 23 accessible without removing one oi' the bellows, it is necessary to increase the radius of the hoods 26 somewhat, as shown, so that the openings shall 25 not be positioned inside the radius of the bellows.

The construction of the valves 4, I4 and I5 and of the sealing device 9 is shown in Fig. 4, which shows part of the valve spindle 5 with valve bodies and valve seats on a larger scale. 'I'he 30 sealing device 9 is conveniently made structurally identical with the valves 4, I4 and I5. Only part of the upper half of the spindle 5, and only the valves I4 and I5 and the sealing device 9 and the corresponding valve seats, are shown in the 35 gure. As may be understood from the gure each of the valves substantially consists of a disc of some elastic material, for instance rubber, which is arranged in an annular groove 3U in the spindle. Each groove is surrounded by two 40 flanges 3I, over which the disc must be forced to place it in the groove. Each disc consists of an inner nave-shaped portion 32 (that extends within the spindle groove and is retained therein in its place on the spindle), a thinner central por- 45 tion 33, and an outer heavier portion 34, which latter is the real sealing member and is intended to be in contact wth the valve seat when the valve is closed. As previously stated, the valves I4 and I5 are located on oppositesides of vacuum 50 chamber I0. Fig. 4 shows the position of the valve at the moment when the spindle 5 has been moved so far to the left (having almost completed its stroke) that the yvalve I5 has just come in contact with the seat 35. Under the influence of 55 the diierence of pressure (air pressure in chamber 8 and partial vacuum in chamber IIJ) acting on the valve, the valve I4 is still kept in contact with the valve seat 36. This is made possible by the great elasticity of the valve body, whose stress 60 tending to hold it in4 contact with its seat exceeds the said differential air pressure until the spindle 5 reaches the position shown in Fig. 4. In that position the elastic tension of the valve just barely suiices to balance the existing dierence of pres- 05 sure, so that when the spindle 5 moves farther to the left beyond the position shown, the valve I 4 cannot yield any farther in relation to the spindle and separates from the seat 36 to permit equalization of pressures in chambers 8 and I Il. At the end 70 of the spindles movement tothe left, it occupies the positionshown on the valve in broken lines and the valve I4 occupies the position 31 shown in broken lines. As the valve I4 is thus not opened until the valve I5 is closed, no free passage will 'I5 be formed from the atmospheric chamber I to the vacuum chamber I I through the pulsatOr during the' moment of reversing.

The operation just described refers only tothe behavior of the individual valves. The following description fully explains the mode of operation of the pulsator as a whole.

With the spindle at the left, as shown in Fig. 2, air entering through strainer 2 and channel 3 flows through chambers'l and I and channels 68 and 'I0 to chamber I3 and the interior I9 of the bellows I1 and, by expanding the bellows, forces air out of the surrounding chamber 2l through the channel 22 toward the chamber 20 surrounding bellows I6. At the same time air is exhausted from inside of bellows I6 through chamber 6, channels 61 and 66, chambers 6 and I0, channel II and nipple I2.

Under these conditions, the head 48 of bellows I6 moves toward the right until it contacts the end of the spindle 5 and forces rit toward the right, bending valves 4 and I5 (as valve I4 is shown in Fig. 4 but in the opposite direction),

until valve I4 contacts with its seat (as valve I5 is shown in Fig. 4) and then still further to the right until valves 4 and I5 are forced away from their seats and the pressures on the two sides of each are equalized, allowing them to assume their normal positions on the spindle with valve I5 in the center of chamber I3 and valve 4 closing the opening between chambers I and 1.

Connections are now reversed and atmospheric pressure from chamber I can flow through chamber 6 into bellows I6 to expand it and force air from chamber 20 through channel 22 to chamber 2l and air from inside bellows I'I will be exhausted through chambers I3 and |0, channel II and nipple I2. The head of bellows I1 will soon contact with the right hand end of spindle 5 and push it toward the left, until the valves are forced to the position shown in Fig. 2 and the cycle will be repeated.

In the actual pulsator the spindle 5 has a loose fit or slight clearance in the guide bearing at the right sufiicient to prevent the spindle from binding when it is guided, at the left, by the bow 56 of the spring 55.

The great elasticity of the valve bodies may, according to the invention, be utilized for the construction of an unparted or one-piece valve housing, as it is possible in assembly to force the valves through the openings of the valve seats, as indicated in Fig. 11, by forcing the valve stem and the valves carried thereby axially through the valve housing. 'Ihe valve housing can therefore be made of one piece in which a central hole is bored, after which grooves are turned from the inside of this bore to form the chambers I, 6, 1, 8, Ill, and I3. To dismount the pulsator. the valve bodies are forced in the opposite direction through the openings of the valve seats.

The sealing device 9 consists, as before stated. of a valve disc of the same kind as the valves I4 and I5. The disc is movably arranged in a groove 39 in the spindle 5. The nave-shaped inner portion 32 forms a tight joint with the flange 3l in the position shown. After the valve disc I4 has assumed the position 31, the right side of the disc 9 is exposed to vacuum, while its left side is subject to atmospheric pressure. A completely tight joint is therefore insured by the difference of pressure acting on the disc 9. The outer heavier portion 34 of the disc 9 is inserted in a V-shaped groove 40, against the walls of which it is maintained by the existing difference of pressure. so that here also a completely tight joint isinsured.l

When the spindle moves to the opposite position the disc 9 is deformed in a manner similar to the described deformation of discs I4 and I5,

so that a tight joint is maintained between the -disc and its seat in the valve housing until the momentv when the tensin in the disc becomes sumciently great to prevent it from further following the movement of the spindle. At this time, however, a reversal of the pressure on both sides of the disc 9 takes place, so that the nave 32 is quickly thrown over to the opposite surface of the groove 39. During this moment of reversal a leakage, although it be a very small one, occurs between the disc 9 and the spindle, because a certain play, amounting to some tenths of a millimeter, should be allowed between the disc and the spindle in radialdirection. After the moment of reversal a completely tight joint is established. 'I'he amount of air leaking past the sealing device during the moment of reversal is very small, being limited to one or perhaps a few per cent of the amount of air passing through pulsators having valve discs ofthe construction heretofore used. It is possible to avoid this insignificant leakage by using a sealing member 9 which has so great elasticity and shape-changing capacity that the portion of the tightening member fitting to the spindle can follow the whole movement of the spindle without causing too great a resistance.

Alternatively the valve I4 can be modified as shown in Fig. 5. As so modified it comprises a ring-shaped portion 4I of approximately square section, which at its outer edge is connected to a disc-shaped annulus 42, which extends into a groove 43 in the spindle. y 'I'he spindle 5 is provided witha flange 44 which is positioned to contact with alshoulder 45 on the inside of the annular portion 4I. In tensionless state the valve body has the shape indicated by dotted lines at 46. In the position shown infull lines the valve body is maintained on its seat 36, by pressure pared with the embodiment shown in Fig. 4 the latter-embodiment has the advantage that the valves are forced to open at an accurately fixed position of the spindle independent of the elastic tension of the valve body. Further, the valve body proper may be made of a less elastic material than the disc-shaped portion 42, or even of entirely unelastic material.

Other embodiments of the valve body are within the scope of the invention. For example, it is practicable to substitute for the valve 4I the valve shown in Fig. 6, in which the parts 4|' and 42 connect with each other at a greater radial distance from the spindle than the corresponding parts 4I and 42 shown in Fig. 6. With this arrangement the part 42 can be allowed to be considerably less elastic than the corresponding part 42 of Fig. 5. Also other constructions are possible. In order, however, to meet the requirements of the present invention, that portion of the valve body which is to contact with the valve seat must 4 less mutable s it is open te the objection that the friction can hardly be kept at a constant and desirable low value.

InFlgs.1and2itisassumed tl'iai.thechani ber I for air` is provided with a single valve disc 4 which alternately contacts with'valve seats arranged on both sides thereof. Such a construction may be used to advantage if the valve disc essary in case valve discs of a construction similar i to that shown in Figs. 5 or 6 be used.

Each of the bellows I6 and I1 comprises two end pieces 41 and 48, connected one with the other by a substantially cylindrical plaited Wall 49, as shown in Fig. 7. The plaiting of the said wall 49 is determined by two spiral springs 50 .and 5I provided outside and inside the same,

which tend to keep the bellows stretched, so that the end piece 48 contacts with the cap 26 when the -pulsator is at rest. The end piece 41 consists of a short mainly cylindrical portion provided with a horizontal ilange to which the wall 49 is fixed. The end piece 41 is made of rather still? rubber or similar material and the cylindrical portion that iits around the nipple-like portion 52 of the pulsator housing a is so made that, when free and in tensionless state. it is slightly tapered or conical, as shown in Fig. 12. When this piece is forced onto the part 52, it is stretched to a cylindrical form and then tightly hugs the part 52. l

The end-piece 48 is a more or less rigid circular disc which at the circumference is tightly iixed to the bellows wall 49. As the end wall 48 moves forth and back in the hood 26 during the operation of the pulsator, it may be provided with a lining in order to prevent the wall 49 from being worn by sliding against the inside of the hood 26. The lining may consist of a metal ring 53 as shown in Fig. '1.

On the end piece 48 there is in the interior of the bellows a lug-shaped hollow portion 54 (see Figs. 2 and 8) having at the base a somewhat smaller diameter than farther out, so that one end of a spring 55 can be retained therein. Spring 55 consists of three portions: the iirst wound like the main spring of a clock and having its inner turn adapted to fit closely in the groove in the lug 54, as shown in Fig. 2; the second a closely wound cylindrical portion as shown in Fig. 2, and the third a bow 56 embracing the neck 51 on spindle 5, as shown in Figs. 2 and 8. Outside the neck 51 the spindle is provided with a head 58, bounded by conical surfaces and retaining the bow 56. As shown in Fig. 2 only the left hand end of the spindle 5 is provided with a head 58.

'I'he springs 50 and 5I and the spring 55, together with the ange 58, form a fixing device" which-when the pulsator is not in operationholds spindle 5 and the valves carried thereby enough toward one end to keep the valves closed so that the pulsator will start when connected to a source of partial vacuum. It also keeps the wall 48 in a fixed position so that the volume of the chamber I8 is xed. As the bellows n is kept wholly trache by the springs n and 5I, thetotal volume of the two bellows il thus iixed. provided. that there is no difference -between the pressure inside and outside the bel'- lows, which is of course the case when the pulsator is not operating. But when the volume of the bellows is fixed, the total volume of chambers and 2| and the amount of air enclosed therein is also fixed. Thisconstancy of volume is of great importance in counteractihs POSSible small leakagesin the walls of the chambers which, although they would not immediately entail dimculties of operation, nevertheless in the long run could cause disturbances by increasing or reducing the total quantity of air enclosed in the two chambers.

The tension of the spring 55 should of course not be so great that it counteracts to an appreciable degree the movements of the bellows during the operation of the pulsator. Nor should it be so great that it can reverse the valve system against the eect of the pressure diflerences operative upon the valves. 'I'he arrangement should act, and does act, to accomplish the purpose specified'only when the pulsator is out of operation.

By the above described xing device, even if the tension'of the spring 55 be very weak, a certain asymmetry of the pulsator results. By suitably determining the tension of the spring, the asymmetric forces caused by the xing devvice may be reduced to such magnitude that the degree of non-uniformity of the pulsator can per cent, which will not in any way be objectionable.

'I'his non-uniformity may also easily be com-` pensated by making the throttle devices 28 asymmetric, so that a greater pressure is required to 4drive the air in the one direction than in the opposite direction. This asymmetry may easily be so determined that it exactly compensates the action of the spring 55. Such an asymmetry of the throttling devices 23 may be effected, for example, by making one end of each channel oriiice somewhat larger than the other. If the channel consists of a hole bored in a plane wall, it may be suicient to make the end of the bore more or less conical or bell-mouthed.

Asymmetry of the throttling devices may be effected in other ways. For instance, they may to advantage be arrangedV as shown in Fig. 9. The throttling devices are in this gure shown as short tubes each having one closed coneshaped end provided with a central hole. These elements act to a certain degree as outow nozzles, and a higher pressure is therefore required for the throughiiow in the one direction than in the other, in order that a given amount of air shall pass through during the same time. To regulate the asymmetry some of the parts 59 may be turned in the one direction and some in the other, so that they more or less compensate each other.

When the pulsator is at rest its movable parts occupy the position shown in Fig. 2. 'They are be reduced to as small a ngure as one or two brought into this position by the hereinbefore aims# so determined that, when the chamber ls is connected with vacuum, the bellows as far as possible is completely compressed by the amount of air thereby expanding infthechamber 20. The amount of air passing through the throttling devices 23 during operation will thereby be as great as possible.

The dimensions and elasticity of the bow 66 should be so determined in relation to the head 58 that the bow can be forced over the head when the parts of the pulsator are assembled. The conical surface o! the head 63 with which the bow 66 contacts should also have such a cone angle that the bow can be forced over the head in disassembling also.

The pulsation chambers 6, 1, 3 and I3 which, as described above, communicate `by pairs with each other, also communicate with four nipples 6I, 62, 63 and 64. Of these 63 and 64 communicate with each other over chamber I3. For establishing communication between the abovementioned annular chambers and the nipples, channels in the form of vertical bores 65, 66, 61, 68, 63 and 'I0 are provided and are positioned tangentially in relation to the chambers 6, 1, 8 and I3. By this tangential location a connecting opening of suiciently great area is obtained between each channel and the corresponding annular chamber with small dimensions of the valve housing.

In the foregoing description it has been assumed that the pulsator works with'and is driven by a partial vacuum. It may, however; to the same advantage be used for generating pulsations between any two different absolute pressures, which may either be' both lower than, or both higher than, or one above and the other below, atmospheric pressure. Also, it may be used with other media than air, for instance a liquid. In particular, it is not necessary' that the fluid flowing back and forth between the two closed chambers should be air. This iiuicl may consist of some suitable liquid, which has certain advantages; for instance, it would permit of the more ample dimensioning of the throttling orifices.

The bellows need `not have the specific construction described.` For the springs 5l may be -substituted two sets of rings, the Fig. '1 of the drawings being consistent, also, -with such a modication. It is possible, indeed, to dispense entirely with rings or springs, as there is no considerable over-pressure'inthe bellows during operation.

What I claim and desire to protect by Letters Patent is:

l. A milking machine pulsator comprising a valve casing having a longitudinal bore provided with valve seats, the valve casing having passages adapted to communicate respectively with sources of high and low fluid pressure, a valve spindle reciprocable in said'bore,v two fluid pulsation chambers surrounding the' spindle, valve mechanism carried by said spindle and adapted in one position of the spindle to connect one of-said pulsation chambers with said high pressure uid passage and the other yof said pulsation chambers with the low pressure iluid passage and in its other position lto reverse said connections, and a sealing device carried by the spindle and maintaining saidfpulsation chambers separated'in both positions of the spindle.

2. A milking machine rpulsator 'comprising a valve casing having a'longitudinal bore provided with valve seats, the valve casing having passages adapted to communicate respectively with sources o! high and low iiuid pressure, a valve spindlereciprocable in said bore, two iluid pulsation chambers surrounding the spindle, valve mechanism carried by said spindle and adapted in one position of thespindle to connect' one of said pulsation chambers with'said high pressure fluid passage and the other of said pulsation chambers with the low pressure duid passage and in yits other position to reverse said connection, and a sealing device carried by the spindle and maintaining said pulsation chambers separated in both positions of the spindle, said sealing device comprising an annular disc surrounding the spindle and whose inner and outer marginalwalls extend luto grooves in the spindle and bore wall respectively.

3. A milking machine pulsator comprising a valve casing having a longitudinal bore provided with valve seats, the valve casing having passages adapted to communicate respectively with sourcesr of high and low iiuid pressure, a valve spindle reciprocable in said bore, two fluid pulsation chambers surrounding the spindle, valve mechanism carried by said spindle and adapted in one position of the spindle to connect one of said pulsation chambers with said high Vpressure vfluid passage and the other of said pulsation chambers with the low pressure fluid passage and vin. its other position to reverse said connection, andr a sealing device carried by the spindleand maintaining said pulsation chambers separated in both positions of the spindle, said sealing device comprising an annular exible disc surrounding the spindle and whose inner and outer marginal walls extend into recesses in the spindle and bore wall respectively, one of said recesses being substantially wider than the thickness of the part of the disc position therein.

4. A milking machine pulsator comprising a valve casing having a longitudinal bore provided with valve seats, the valve casing having passages adapted to communicate respectively with sources of high and low fluid pressure, a valve spindle reciprocable in said bore, two iluid pulsation chambers surrounding the spindle, valve mechanism' carried by said spindle and adapted in one position of the spindle to connect one of said pulsation chambers with said high pressure uid passage and the other of said pulsation chambers with the low pressure fluid passage and in its other position to reverse said' connection, and a sealing device carried by the spindle and maintaining said pulsation chambers separated in both positions of the spindle, said sealing device comprising an annular disc whose inner and outer marginal portions contact respectively. with the spindle and the wall of the'bore, said disc having a. limited sliding play along one of the last two named members but contacting tightlyl with both members in either end position of the spindle. j

5. A milking machine pulsator comprising a valve casing having a longitudinal bore provided with valve seats, the valve casing having passages adapted to communicate respectively with sources of high and low fluid pressure, a valve spindle reciprocable/in said bore, two uid pulsation chambers surrounding the spindle,` valve mechanism carried by.' said spindle and adapted in Yone position of theA spindle to connect one of said pulsation chambers :with `said high pressure fluid y.passage and the other of said ypulsation chambers with the low pressure iluid passage and in its other position to reverse said con-neco inner marginal portion'of the disc is adapted to slide in the movement of the spindle and against the side walls of which groove the inner portion of the disc is adapted to tightly seat in opposite end positions of the spindle.

6. A milking machine pulsator comprising a valve casing having a longitudinal bore provided with valve seats, a. valve spindle reciprocable in said bore, a high pressure chamber surrounding the spindle and adapted to communicate with a source of high pressure, a pulsation chamber surrounding the spindle on one side of the high pressure chamber, a second pulsation chamber sur-l`l rounding the spindle on the other side Yoil-the high pressure chamber, a third pulsation chamber surrounding the spindle beyond.' the second pulsation chamber and connected with the rst pulsation chamber, a low pressure chamber surrounding the spindle beyond the third pulsation chamber, a fourth pulsation chamber surrounding the spindle beyond the low pressure chamber and connected with the second pulsation chamber, valve means carried by the spindle and adapted to connect the high pressure chamber alternately with the pulsation chamber on opposite sides thereof, a valve carried by the spindle adapted to alternately connect and disconnect the third pulsation chamber with the low pressure chamber, a valve carried by the spindle and adapted to alternately connect and disconnect the fourth pulsation chamber with the low pressure chamber, and a sealing device surrounding-the spindle and separating the second vanni third pulsation chambers.

7. A milking machine pulsator comprising a valve having a longitudinal bore, a valve spindle reciprocable therein, iiuid passages adapted to communicate respectively with sources of high and low pressure, a high pressure chamber surrounding said spindle and adapted to communicate with said high pressure fluid passage, pulsation chambers surrounding said spindle on opposite sides of the high pressure chamber, opposing valve seats between the respective pulsation chambers and the high pressure chamber, and 'an annular flexible valve surrounding the spindle and extending into the high pressure chamber between said valve seats, said valve being adapted by its elasticity to be held against either seat by unbalanced pressures on opposite sides thereof during the movement of the spindle in the direction to unseat it and adapted in the further movement of the spindle in said direc- Y tion and upon'the balancing of said pressures to immediately leave said seat and snap onto the opposite seat.

8. A milking machine pulsator comprising fluid passages adapted to communicate respectively with sources of high and low pressure, two fluid chambers and a conduit allowing communication at a regulated rate back and forth between them, means providing two air pulsation chambers adapted -for connection with teat cups, and valve mechanism operable in one position to connect one pulsation chamber with said high pressure iluid passage and the other pulsation chamber with the low pressure fluid passage and in another position to reverse said connections.. one at least of said :duid chambers being bounded by a movable wall of a bellows, which wall is also a. wall of one oi said pulsation chambers, said pressure reversals effecting contraction and expansion of the bellows and controlling the operation of said valve mechanism, said bellows having a exible wall comprising a cylinder of flexible material and a helical spring maintaining said material in plaited form and whose tension tends to maintainthe bellows expanded, thereby requiring an exterior pressure to compress the bellows.

9. A milking machine pulsator comprising fluid passages adapted to communicate respectively with sources of high and low pressure, two fluid chambers and a conduit allowing communication -at a regulated rate back and forth between them, means providing two air pulsation chambers adapted for connection with teat cups. and valve mechanism operable in one position to connect one pulsation chamber with said high pressure uid passage and the other pulsation chamber with the low pressure uid passage and in another position to reverse said connections, one at least of said fluid chambers being bounded by a movable wall of a bellows, which wall is also a wall of one of said pulsation chambers, said pressure reversals effecting contraction and expansion of the bellows and controlling the operation of said valve mechanism, and means to maintain said bellows in one of its extreme positions when the pulsator is disconnected from its actuating uid source.

10. A milking machine pulsator comprising fluid passages adapted to communicate respectively with sources of high and low pressure, two uid chambers and a conduit allowing communi-V cation at a regulated rate back and forth between them, means providing two air pulsation chambers adapted for connection with teat cups, valve mechanism operable in'one position to connect one pulsation chamber with said high pressure fluid passage and the other pulsation chamber with thev low pressure iluid passage and in another position to reverse said connections, one at least of said uid chambers being bounded by a movable wall of a bellows, which wall is also a wall of one of said pulsation chambers, said pressure reversals effecting contraction and expansion of the bellows and controlling the operation of said valve mechanism, and means to maintain said bellows in one of its extreme positions when the pulsator is disconnected from its actuating uid source, said means including a closed coil helical spring xed to the movable wall of the bellows.

11. A milking machine pulsator comprising fluid passages adapted to communicate respectively with sources of high and low pressure, two uid chambers and a conduit allowing communication at a regulated rate back and Aforth be-4 tween them, means providing two air pulsation chambers adapted for connection with teat cups, valve mechanism operable in one position to connect one pulsation chamber with said high pressure uid passage and the other pulsation chamber with the low pressure fluid passage and in another position to reverse said connections, one at least of said fluid chambers being bounded by a movable wall of a bellows, which wall is also a wall of one of said pulsation chambers, said pressure reversals effecting contraction and expansionof the bellows and controlling the operation of said valve mechanism, said bellows having a exible wall comprising a cylinder oi ilexible material, a helical spring maintaining said material in plaited formand tending to mainl tain the bellows expanded, and a helical spring iixed to the movable wall of the bellows, said springs constituting a iixing device adapted, when the pulsator is not in operation, to maintain the I in another position to reverse said connections,'

one at least of said iiuid chambers being bounded v by a movable wall of a bellows, whichwall is g also a wall of one of said pulsation chambers, said pressure reversals eiecting contraction and expansion of the bellows and controlling the operation of said valve mechanism, said bellows having a ilexible wall comprising a cylinder of aoviiexible material and a helical spring maintaining said material in plaited form and whose tension tends to maintain the bellows expanded, a tightly wound helical spring xed at one end to the movable wall of the bellows, and a member 35, on the spindle which the other end of said spring engages when the pulsator is not in operation, said springs constituting a fixing device adapted to maintain the valve in one end position thereof and the valve mechanism in suitable position for d0 starting.

13. A milking machine pulsator comprising fluid passages adapted to communicate respectively with sources of high and low pressure, two huid chambers and a conduit allowing communication at a regulated rate back and forth between them, means providing twov air pulsation chambers adapted for connection with teat cups, and valve mechanism operable in one position to connect one pulsation chamber with said high pressure iiuid passage and the other pulsation chamber with the low pressure uid passage and in another position to reverse said connections, one at least of said iiuid chambers being bounded by a movable wall of a bellows, which wall is also a wall of one of said pulsation chambers, said pressure reversals effecting contraction and expansion of the bellows and controlling the operation of said valve mechanism, means tending to maintain the valve mechanism in one of its end positions when the pulsator is disconnected 6l)".trom its source of actuating iiuid, thereby creating a measurably asymmetry in the operation of the pulsator, and means to compensate for such asymmetry, said last named means com- 65 prising throttling members in said conduit pro- L viding greater resistance to fluid ow in one direction than in the other.

414. A milking machine pulsator comprising a valve casing having a longitudinal bore provided 70 with valve seats, fluid passages adapted to communicate respectively with sources of high and low pressure, two uid pulsation passages adapted for connection with teat cups, and valve mechanism operable in one position to connect one 75 pulsation passage with said high pressure uid passage and the other pulsation passage with the low pressure iiuid passage and in another position to reverse said connections, said valve mechanism comprising a valve spindle reciprocable in said bore and valves carried by the spindle, said l spindle being adapted to move one valve toward its seat while another valve is being moved in a direction to unseat it, each valve having a seatcontacting surface which is movable relative to the spindle and which is held on its seat by the 10 unbalanced pressures specified while the valve spindle is moving in the direction to eiiect its unseating and until the other valve is seated.

15. A milking machine pulsator comprising a valve casing having a longitudinal bore provided 16 with valve seats, fluid passages adapted to communicate respectively with sources of high and low pressure, two iiuid pulsation passages-adapted for connection with teat cups, and valve mechanism operable in one position to connect one 20 pulsation passage with said high pressure fluid passage and the other pulsation passage with the low pressure fluid passage and in another position to reverse said connections, said valve mechanism comprising a valve spindle reciprocable in said bore and valves carried by the spindle, said valves comprising iiexible discs having seat contacting surfaces whose marginal portions are movable relative to the spindle and are held on their seats by unbalanced pressure while the valve spindle is moving in a direction to effect their unseating, said spindle being adapted, in moving in a direction to move one valve toward its seat, to effect the seating thereof before another seated valve is unseated by its limit of iexliliV ibility under existing pressure conditions being exceeded.

16. A milking machine pulsator comprising a valve casing having a longitudinal bore provided with valve seats, uid passages adapted to communicate respectively with sources of high and low pressure, two uid pulsation passages adapted for connection with teat cups, and valve mechanism operable in one position to connect one pulsation passage with said high pressure uid passage and the other pulsation passage with the low pressure iluid passage and in another position to reverse said connections, said valve mechanism comprising a valve spindle reciprocable in said bore and valves carried by the spindle and having seat-contacting surfaces which are movable relative to the spindlev and which are held on their seats by unbalanced pressures while the valve spindle is moving in the direction to effect their unseating and which are unseated at the completion of said valve-unseating movement of the spindle, each valve comprising an annular disc whose inner marginal portion is secured to and moves with the spindle, whose mediate portion is comparatively thin and 60 flexible and Whose outer portion provides a seat contacting member which is substantially thicker than the mediate portion, thereby providing a substantially elastic valve having a comparatively rigid seating portion.

17. A milking machine pulsator comprising a valve casing having a longitudinal bore -provided with valve seats, iiuid passages adapted to communicate respectively with sources of high and low pressure, two fluid pulsation passages adapt- ,m ed for connection with teat cups, valve mechanism operable in one position to connect one pulsation passage with said high pressure iiuid passage and the other pulsation passage with the low pressure fluid passage and in another posiu tion to reverse said connections, said valve mechanism comprising a valve spindle reciprocable in said bore and valves carried by the spindle and 'having seat-contacting surfaces which are movable relative to the spindle and which are held on their seats by unbalanced pressures while the valve spindle is moving in the direction to effect their unseating and which are unseated at the completion of said valve-unseating movement of the spindle, and flanges carried by the spindle and adapted to engage and positively unseat the valves after a predetermined movement of the valve spindle.

18. A milking machine pulsator comprising a valve casing having a longitudinal bore provided with valve seats, iluid passages adapted to communicate respectively with sources of high and low pressure, two uid pulsation passages adapted for connection with teat cups, valve mechanism operable in one position to connect one pulsation passage with said high pressure fluid passage and the other pulsation passage with the low pressure fluid passage and in another position to reverse said connections, said valve mechanism comprising a valve spindle reciprocable in said bore and valves carried by the spindle and having seatcontacting surfaces which are movable relative to the spindle and which are held on their seats by unbalanced pressures while the valve spindle 4is moving in the direction to effect their unseating and which are unseated at the completion of said valve-unseating movement of the spindle, each valve comprising an annular flexible and elastic body whose inner portion is secured to and moves with the spindle and Whose outer portion is adapted to engage the valve seat, a shoulder on y said outer portion of the valve body, and a Iia'nge carried by the spindle and adapted,vin the valveunseating movement of the spindle, to engage said shoulder and positively unseat the valve after the a valve casing having a longitudinal bore provided with valve seats, fluid passages adapted to communicate respectively with sources of high and low pressure, two fluid pulsation passages adapted for connection with teat cups, and valve mechanism operable in one position to connect one pulsation passage with said high pressure iluid passage and the other pulsation passage with the low pressure fluid passage and in another position to reverse said connections, said valve mechanism comprising a valve spindle reciprocable in said bore and Valves carried by the spindle and having seat-contacting surfaces which are movable relative to the spindle and which are-held on their seats by unbalanced pressures while the valve spindle is moving in the direction to eiect their unseating and which are unseated at the completion of said valve-unseating movement of the spindle, said valves comprising exible anarcanos nular discs whose inner marginal portions are confined in grooves in the spindle and whose outer marginal portions are held on seats on the wall of saidy bore by unbalanced pressures as specifled, until, in the movement of the spindle-in the direction to unseat them, their limit of flexibility is exceeded.

20. A milking machine pulsator comprising a valve casing having a longitudinal4 bore provided with valve seats, uld passages adapted to communicate respectively with sources of high and low pressure, two -fluid pulsation passages adapted for connection with teat cups, valve mechanism operable in one position to connect one pulsation passage with said high pressure iiuid passage and the other pulsation passage with the low pressure fluid passage and in another position to reverse said connections, said valve mechanism comprising a valve spindle reciprocable in said bore and valves carried by the spindle and having seatcontacting surfaces which are movable relative to the spindle and which are held on their seats by unbalanced pressures While the valve spindle is moving in the direction to .efl'ect their unseating and which are unseated at the completion of said valve-unseating movement of the spindle; said valves comprising annular discs whose inner marginal portions are secured to the spindle, said valve spindle and valve casing being adapted to be assembled by the insertion of the spindle axially into said bore, the valve discs being of such flexibility and elasticity as to enable them to distort suillciently to be forced, in said assembly,

' through the annular valve seats'.

21. A milking machine pulsator comprising a valve casing having a longitudinal bore provided with valve seats, fluid passages adapted to communicate respectively with sources of high and low pressure, two uid pulsation passages adapted for connection with teat cups, valve mechanism operable in one position to connect one pulsation passage with said high pressure fluid passage and the other pulsation passage with the low pressure iluldvpassage and in another position to reverse said connections, said valve mechanism comprising a valve spindle reciprocable in said bore and valves carried by the spindle and having seatcontacting surfaces which are movable relative to the spindle and which are held on their seats by unbalanced pressures while the valve spindle is moving in the direction to eilect their unseating and which are unseated at the completion of said valve-unseating movement of the spindle; the valve casing comprising a one-piece cylinder and the valves comprising annular discs whose inner marginal portions are secured to the spindle, said valve spindle and valve casing being adapted to be assembled by the insertion of the spindle axially into said bore, the valve discs being of such flexibility and elasticity as to enable them to distort sumciently to. be forced, in said assembly, through the annular valve seats, thereby allowing the cylindrical valve casing to be made in one piece as specified.

KARL GUNNAR MAGNI.

. cERTIFIcATE- or lcoRREcTIoN.

lPatent'NO. 2,186,255. January 9, 19LLO.

KARL GUNNAR MAGNI. It is hereby certified tha-:t the name of' the assignee in the above numbered patent was erroneously described and specified as".De Laval Separator Company" whereas said name should have 'been described and specified as The De Laval Separator Company, ofl New York, N. Y'. a corporation of New Jersey, as; shown b y `the Irecord of assignments in this office; and thatthe said Let-Y ters Patent should be read with this :correction therein that the same may Aconform to the record 'of' the case in they Patent Office.

Signed and sealed this 19th day of March, A. D. l9LLO'.

y Henry van Arsdalev, (Seal) Acting Commissioner of Patents

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