US2072482A - Compressor or pump - Google Patents

Description

March 2', 1937.

F. E. MYARD Y COMPRESSOR on PUMP Filed Feb. v15, Y1936 Patented Mar. 2, 1937 UNITED STATES eArsu FFIQE GOMPRESSOR R PUB/[P France Application February 13, 1936, Serial No. 63,739

In France February v23, 1935 Claims.

This invention relates to rotary compressors or pumps for gases or liquids of the type comprising a hollow stator, two pairs of blades actuated with a rotary movement around a common axis and turning just with the necessary clearance in the interior of the stator and centred on this common axis, the angular speeds possessed by these two pairs of blades having the same mean value but periodically varied during the cycle in such a way as to have speeds which are alternately slow and more rapid (and this twice for each complete turn of each blade), the consequent volumes produced between the adjacent blades which alternately increase and de- 15. crease permitting, since the whole of the system rotates, the distribution of the fluid to be obtained, the statorbeing provided with apertures of suitable position, form and arrangement for the suction and discharge.

x Withl such rotary compressors or pumps it has been proposed to drive the pairs of blades through a system of elliptical or other non-circular` gear wheels.

According to the present invention, the rota- `2'5 tion of the blades is conveniently obtained by means of a common inputshaft (concurrent with the aforesaid common axis and very considerably inclined thereto) which drives two Cardan joints having the same centre but offset through 90 and of which the output shafts (centred on the common axis) are connected respectively to the two pairs of blades.

In order that the nature of the invention may be more clearly understood, reference will now be made to the accompanying drawing, in

, Fig. 1 is an axial sectional elevation of the compressor on XUX of Fig. 3.

Fig. 2 is a sectional view from the end of the system of cardans and supposing, in this case,

that the input and output axes are brought into common rectilinear alignment (perpendicularly to the plane of the figure) and projected on O.

Fig. 3 is a transverse section along YUY of Fig. 1.

Fig. 4 is a perspective view on a small scale of one of the two pairs of blades.

Figs. 5 and 6 show a side view and section on ZZ (Fig. 5), of a variation, wherein a pair of 50 hollow blades are employed corresponding to a compressor in which the dead spaces are null.

Figs. 'l and 8 show diagrammatically and on a small scale, a system according to the invention destined more particularly for pumping liquids, 5g aspiration being effected through an end piece (Cl. 10S-129) adjacent the axis instead of in the cylindrical zones of the stator, that is to say in opposition to the centrifugal effects and Fig. 9 is a diagram of the variations of the angular speeds corresponding to the Cardan sys- 5 tem.

Referring to this latter gure, it will be found that the well known property of a cardan serving to connect two concurrent shafts inclined one tothe other in the rotary direction is indicated. If 10 one of these shafts (the input shaft, for example) possesses a uniform angular speed defined by the ordinate I, the other shaft is then actuated at a Variable speed dened by the curve II which, twice per turn, passes periodically 15 through the same Values.

Consequently, if the same input shaft simultaneously drives a second output shaft centred on the former and this by means of a second Cardan joint turned through the 90 relatively to 20 the former, it will be seen that the angular speed taken by this second output shaft will have the variations represented by the curve II.

As shown in the drawing, a stator k is provided, closed by end plates h and z' and enclosing 25 two pairs of blades w a' and b b connected respectively to the concentric shafts c and d driven simultaneously by the shaft e by means of two cardans centred at O and oifset by 90. The blades a, and a', in turning at a great speed, pass 30 their actual or mean position to take the respective place of the blades b and o while, at the same time, the blades b and b, turning at a small speed, come to the corresponding place of the blades a and a. 35

Thus, between the blades a and b on the one hand and a and b on the other hand, the v01- umes will decrease and if a fluid is originally present therein, it will be subjected to a discharge made possible by reason of the discharge 40 ports` R and R respectively.

On the contrary and during this same instant, the spaces between the blades a and b on the one hand and b and a on the other hand will increase and produce a lling action, this aspira- 45 tion being effected through the inlet ports A and A'. Of course, in the case of an air compressor, these latter open directly to the atmosphere.

The first Cardan joint which connects the shaft e to the shaft c solid with the blades b b is formed of the cross f of which two pivots articulate in the forli c carried by the shaft c while the other pivots of this cross f articulate in the fork e1 carried by the shaft e.

The second Cardan joint which connects the same shaft e to the tubular shaft d solid with the blades a a', is constituted by the ring g provided with four pivots placed in the cross. Two of these articulate in the fork d carried by the shaft d and the two others in the fork e2 carried by the shaft e.

Needle bearings are preferably provided, although smooth bearings could be utilized. In a general way, numerous variants concerning the mechanical construction of these Cardan joints are possible within the scope of the invention without it being necessary to enumerate or detail them.

It should be noted that the periodically varied angular speeds of the shafts c and d are utilized in their relative, that is to say differential, form. For each cardan, these alternately accelerated and then retarded speeds have variations of which the amplitude is a function of the angle a made by the inclined shaft e to the concentric shafts c and d.

The shaft e turns in the box y by means of needle bearings but (and it is the same for the movable assembly of blades) any suitable mechanical variants as regards the bearings (smooth, ball, roller or like bearings) as well as all the details of embodiment relating to this machine, may be modified in accordance with the invention.

The pairs of blades ought to be as light as possible, to minimize the inertia, as they have to be periodically varied. These parts could be cast in a light alloy and subjected to a careful machining (form milling or planing and turning) in their cylindrical zones (hub and peripheral portions) and in the end faces since the fluidtightness depends on this machining and the reduction of clearance to the minimum. Thin and very light rings forming packing segments may be carried by the blades properly speaking at desired points.

In order to reinforce the base of the blades, there may be provided one or more series of hollow enlarged parts (each series being situated in a common plane normal to the axis) the hollow and plain ones corresponding on the successive blades, or use may be made of helicoidal blades.

It is preferable to provide for each of the pairs of blades, at a suitable extremity, a flat end or disc solid with the hub concerned and connected to the two corresponding blades by fitting therein or otherwise. For the blades a a this end will be on the box side and for the blades b b on the opposite side.

If it is preferred to perform the machining of the hubs by turning, the blades would be attached to them by dovetails or otherwise, as indicated in Figs. 5 and 6.

In this example, moreover, hollow blades are shown having in the transverse direction a dimension which increases gradually from the base to the tip and of which the enlargement is such that periodically these blades come practically into contact at each maximum approach. There is thus obtained the lelimination of dead spaces. This also is shown in the arrangement of Figs. 7 and 8.

It is obvious that in all cases the admission and exhaust ports permit coverings, advances or retardations in the distribution desired. Finally, a non-return valve could usefully be provided in the outlet.

In the case of a heavy fluid or liquid, it would probably be very advantageous to facilitate the aspiration of this fluid by locating the inlet ports A and A near the hub, thus making u'se of the phenomena of centrifugal action and displacement instead of subjecting such fluid to opposition due to such force. Naturally the form, position and arrangement of these two apertures A and A as well as the arrangement and disposition of the blades will be combined with a View to the maximum flow efficiency that this system, which is at the same time volumetric and centrifugal, may have. The aspiration will be effected through one end only or from the two ends if preferred.

The invention is not limited to the precise forms or details of construction described, as these may be varied to suit particular cases.

What I claim and desire to secure by Letters Patent of the United States of America is:-

1. A rotary compressor or pump of the type set forth comprising a hollow cylindrical stator, two pairs of rotor blades mounted within the stator to rotate about the stator axis, a driving shaft exterior of the stator and having an axis concurrent with but inclined to the axis thereof, two Cardan joints connected to said driving shaft and having the same centre but offset through two output shafts from the said two Cardan joints extending into the stator and having axes coincident with the stator axis, driving connections between one output shaft and one pair of rotor blades, driving connections between the other output shaft and the other pair of rotor blades, and inlet and discharge ports in the stator for the purposes set forth.

2. A rotary compressor or pump of the type set forth comprising a hollow cylindrical stator, two pairs of rotor blades mounted within the stator to rotate about the stator axis, a driving shaft exterior of the stator and having an axis concurrent with but inclined to the axis thereof, two Cardan joints connected to said driving shaft and having the same centre but offset through 90 formed as a composite Cardan joint, twooutput shafts from the said two Cardan joints ex, tending into the stator and having axes coincident with the stator axis, driving connections between one output shaft and one pair of rotor blades, driving connections between the other output shaft and the other pair of rotor blades, a casing enclosing the composite Cardan joint and in fixed relation with the stator, bearings in said casing for the driving and output shafts, and inlet and discharge ports in the stator for the purposes set forth.

3. A rotary compressor or pump of the type set forth comprising a hollow cylindrical stator, two pairs of rotor blades mounted within the stator to rotate about the stator axis, a driving shaft exterior of the stator and having an axis concurrent with but inclined to the axis thereof, two Cardan joints connected to said driving shaft and having the same centre but offset through 90, two concentric output shafts from the said two Cardan joints extending into the stator and having an axis coincident with the stator axis, driving connections between the inner output shaft and one pair of rotor blades, driving connections between the outer output shaft and the other pair of rotor blades, and inlet and discharge ports in the stator for the purposes set forth.

4. A rotary compressor or pump of the type set forth comprising a hollow cylindrical stator, two pairs of rotor blades mounted within the stator to rotate about the stator axis, a driving shaft exterior of the stator and having an axis conings in said casing for the driving and output shafts, and inlet and discharge ports in the stator for the purposes set forth.

5. A rotary compressor or pump as claimed in claim 4 comprising an end plate to the stator integral with the casing of the composite Cardan joint, a bearing in said end plate for the outer output shaft, another end plate for the other end of the stator and a bearing in this further end plate for the end of the inner output shaft. 10

FRANCIS EMILE MYARD.

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