US1862954A - Rotary pump machine - Google Patents

Description

June 1932- e. E. T. EI'YSTON ROTARY PUMP MACHINE 3 Sheets-Sheet 1 Filed Dec. 21, 1928 QQQCQJQDT June 14, 1932. G. E. r. EYSTON ROTARY PUMP MACHINE June 14, 1932.

G. E. T. EYsTN ROTARY PUMP MACH INE Filed D90. 21, 1928 3 Sheets-Sheet 3 rotor,

Patented June 14, 1932 entree STATES PATENT oer-ice GEORGE EDWARD THOMAS EYS TON,

OF'LONDON, ENGLAND, ASSIGNOR T0 POWERPLUS (1927) LIMITED, OF LONDON, ENGLAND, A CORPORATION OF GREAT BRITAIN ROTARY PUMP MACHINE Application filed December 21, 1928, Serial No. 327,588, and in Great Britain December 23, 1927.

This invention comprises improvements in and connected with rotary pump machines and is concerned with that type of machine which comprises a piston body or rotor fitted with vanes or blades and eccentrically mounted in an outer casing so as to form a crescentshaped working chamber through which the vanes move in pumping fluid from an inlet to an outlet of the pump casing. In this type 1 of machine, termed crescent-chamber type the piston vanes are mounted in longitudinal slots or recesses in the rotor and they may have a relative sliding movement in the slots or recesses as they sweep round in the casing or the movement may be of sliding-rocking :1 erned as to their position or otherwise.

The present invention has for its principal object to provide, in machines of this type, an improved form of bearing for the blades in the recesses or slots of the piston body or this bearing enabling vanes or blades of light construction to be employed while minimiz'ng friction losses in the operation of these machines. It will be realized that it is of advantage to have blades of light con- 9'; struction as thereby centrifugal stresses and re-action forces are brought within low limits, and friction may be reduced, and reduction in friction losses leads to greater efficiency.

According to this invention the sides of the recesses or slots of the rotor are recessed or cutaway in such manner that the vanes or blades have arunning clearance therein over part of their length, while over the remainder of the length of the blades the sides of tl e recesses or slots present projecting and rigid bearing surfaces for the vanes or blades. The invention thus provides a simple manner of decreasing or subdividing the bearing for thin fiat blades and there are no loose bearing parts to be fitted or become deranged or to increase the expense of manufacture of the machines. Lubricant would be supplied only to the bearing surfaces and as theselie close against the blade, the lubricant supply ports will always be covered by the blade and waste of lubricant or undue escape thereof to the.

working chamber of the machine will be pre-. In machines with short blades the vented. bearing may be at one place central of the length of the blade and in cases Where the blades are longer, the bearing surfaces are suitably distributed along the recesses or slots at appropriate distances apart in the length of the blade. In any case, the bearing is at only one place or at separated places and not over the whole of the length of the: blade so that friction may be minimized. Approprlate formation or disposition of the bearing surfaces will still enable blades or vanes of plane, and thus light, construction 7 I to be employed while lubrication also is advantageously efi'ected because it is only necessary to supply lubricant to the constricted or narrowed places where the vanes bear in the recesses or slots. Lubricant can be supplied much more efliciently and simply to localized points than over the whole length of a vane or blade. As Will be realized, the sides of rotor slots or recesses of the nature indicated will have a sort of castellated form in transverse section. The actual bearing parts may be advantageously fitted with anti-friction or hearing liners or surfaces.

The vanes may lie in planes radiating from the central axis of the casing of the machine or from the central axis of the rotor. In the former case, the blades would have a sliding-rocking movement relative to the rotor and oscillatory bearing or trunnion blocks would preferably be provided for them in the slots of the piston body or rotor, the slots of these blocks being of the castellated nature referred to. hen con-. structions are adopted in which the vanes or blades lie in planes radiating from the central axis of the piston body or rotor, the slots in the rotor itself may be given the castellated form, though obviously bearing members or blocks with castellated blade slots may be used mounted fixedly in the slots of the rotor.

Asa modified form of construction, instead of forming the rotor slots with castellations to provide bearing surfaces of the inner extent of the cut-outs e.

nature referred to, the thin blades may be formed in this manner and the rotor slots be of equal width throughout their length, the blades in such a construction thus comprising parts which form bearing surfaces at point or points along their length, while the remainder of the blades is machined out slightly so that their surfaces over these parts have a running clearance in their slots.

In order to enable ready understanding of the invention to be obtained, suitable e:\' amples of construction will now be described with the aid of the accompanying drawings, wherein Figure l is a perspective view of a solid form of piston body or rotor for a machine of the type referred to, part being broken away to show the form of the bearing surfaces in the rotor slots and a vane or blade being shown in one of the slots for purposes of illustration.

Figure 1 is a cross-sectional view of a machine embodying the rotor and vane construction of Figure 1.

Figure :2 is a similar view of F .igure 1 of a modified construction but with the rotor also broken away at the near end and with all of the slots fitted with vanes or blades.

Figure 8 illustrates another example with part broken away to facilitate understanding of the construction.

Figures l and 5 are diagrams to aid in un' derstanding the castellated nature of the bearing surface construction provided in accordance with these improvements.

Figure 6 is a fragmentary view illustrating a modification of the trunnion blocks for construction such as are seen in Figure 3.

Figure 7 is an elevation of a further modified form of trunnion or bearing block.

Figure 8 is a section on the VIIIVHI of Figure 7 and Figure 9 is a plan View of a trunnion block and blade comprising a further modified form of bearing surfaces for the blades of machines of the type referred to.

In Figure 1, the solid rotor body a is intended for fixed mounting on a driven shaft a Figure 1 which passes through the central bore Z) and is mounted eccentrically in an outer casing a having the usual inlet and outlet connections as at M. As seen in these Figures, the rotor has six slots 0 in which the vanes or blades, such as (Z, have relative sliding movement in the well-known manner as the rotor revolves. Thesides of the slots over a greater part of their length are cut away as at so as to provide a running clearance over a large part of the surface of the blade. As will be seen at the upper part of Fig are l, the bearing surface parts f are practically entirely at the end parts of the slots. The section at 1 in Figure l is taken centrally of the length of the rotor (Figure l) to show the It is not essenline tial, of course, that the cut-away parts 6 should have the semi-circular contour shown. This is only for convenience and economy in manufacture, for if desired the cut away parts could extend rectangularly as indicated, say, by the dotand dash lines at g in. Figure 1. It will be obvious, however, that the semi-circular form is the easiest to produce as it may be made by a milling cutter working in from the outer ends of the slots, the cutter being slightly wider than the slots to give the desired clearance to the central part of the blade on each face. The form of the outer end of the slots and the increase of width at the parts e is plainly seen at the lower forward side of Figure 1. The proportionate trans verse dimensions or width of the slots at the parts 6 and f is slightly exaggerated for sake of illustration in Figures 1 and 1 and a si1nilar consideration applies to other figures. In practice the width of the slots at 6 would only be a fraction of a millimetre greater than at 7 (say :2 mm. wide at e and 1 mm. wide at f) so that the blades merely have arunning clearance at 6. At the relatively projecting parts 7 they have a bearing fit in the slots and it will be seen that as the bearing parts of the slots are localized practically at the ends of the slots, friction in the working of the blades is considerably reduced as compared with what it would be if the blades had a bearing over the whole length of the slots. The resultant improvement in the working of the blades will be readily understood and a further advantage is that lubrication is simplified because oil need only be supplied to the parts f instead of along the whole length of the slots. The section at 2 in Figure l is at one end of the rotor a and shows a suitable lubricating duct 7 in the rotor fed by the duct 7' from a central duct in the rotor drive shaft a It will be seen that the duct f is situated near to the circumference of the rotor. In this way, better control of the lubricant supply is obtainable because the outlets from the lubricant supply ducts f are always covered by the blades so that waste of lubricant and undue escape thereof to the working space of the machine are prevented.

In the construction shown in Figure 2, the rotor or piston-body a is of hollow cylindrical form with spaced slots around its periphery. The blades (Z, as before have a relative sliding movement in these slots but the bearing proper is taken in slots h in bearing blocks is mounted fixedly in recesses in the rotor. In this construction the bearing surface in the slots is provided not by cutting away the sides of the slots as in Figure 1 but by cutting away the blades on each face at different places along their length as shown at Z. The slots h are, therefore, of the same width throughout their length. Nevertheless, the bearing of the blades in the slots is only at separated points where the blades have not been cut away at m. This construction, therefore, provides similar advantages to the construction shown in Figure 1, and the parts Z are as easily machined as the parts 6 in Figure 1, because it is readily possible to operate on the outside surfaces of the blades.

Figure 3 shows a similar blade and slot construction to that seen in Figure 2, but whereas in the previous figure (and also in Figure 1), the blades d have been centred in the rotor, in Figure 3 they are intended to lie in planes radiating from the centre of the outer casing of the machine. It will be well understood that with this blade disposition, the movement of the blades relative to the rotor is not a pure sliding movement but a slidingrocking movement and, therefore the bearing blocks 76, with the slots h for the blades, are mounted in their recesses in the rotor so that they may partake of an oscillatory movement as the blades rock, the rotor being cut away in the usual manner at n, to allow the rocking movement. The reference letters applied to the blades and slots in Figure 3 are the same as those in Figure 2.

The diagrams, Figures 4; and 5, are respec tively cross-sectional views of the contiguous bearing surfaces in Figure l and Figures 2 and 3. They are purely fragmentary views and are intended to show the castellated nature of the slot or vane surfaces in cross-section and the nature of the clearances. Only one side of the vanes and slots is shown and the parts are indicated by the same reference letters as in Figures 1 to 3.

According to the modification illustrated by Figure 6, short recesses 0 are provided in the slots of the bearing or trunnion blocks in the region of the bearing surfaces at m to facilitate access ofoil to the bearing between the parts m and the side walls of the slots it. These recesses would face the interior of the rotor from which oil would gain access to the recesses by way of the cutouts at n in the case of Figure 3, or through the slot parts 01/ Figure 2, which need only be rough out since the bearing proper for the blades is in the slots h of the bearing blocks 70 as stated.

The cross-sectional form and the disposition of the recesses 0 are seen again in Figures 7 and 8. These figures illustrate a suitable form which may be given to the hearing or trunnion blocks of constructions such as are shown in Figure 3, for the purpose of imparting lightness to the blocks. As will be seen in Figures 7 and 8, the blocks are bored or recessed on either side at numerous points along their length as at p and this considerably lightens the blocks without detracting from the strength required in them. Where the recesses 0 are situated ports 1" may lead from the bottoms of the adjacent recesses 10 to the slots 72. to allow further supply of lubricant by way of these recesses to the places where the blades take bearing in the slots.

The recesses in the blocks for lightening purposes, may of course, be formed in other ways, for example, by cutting away the block on opposite sides (top and bottom) between the bearing places so as to give it the form of short cylindrical parts joined by relatively narrow horizontal webs. Lightened forms of block of this nature may also be used in constructions such as are shown in Figure 2.

In the constructions so far described, the blades have been substantially plane or flat. This is one of the advantages of this invention, a sub-divided bearing surface being provided and yet the blades being of lightest possible form. If necessary, however, for instance in high speed machines, reinforcing ribs may be fittedacross the blades, as shown by way of example at s in Figure 9. The blade in this figure is of the form shown in Figures 2 and 3 and takes bearing in the slots only at the parts m, the parts cut away at Z having a running clearance in the slot h which is of the'same width throughout its length, except where the ribs 8 are situated where there are enlargements t. The latter are so formed that the ribs do not take any bearing in the slots but have a running clearance, the bearing beingonly over the parts m of the blade as stated. The bearing is at three places along the length of the blade, instead of at only two in Figures 2 and 3, but obviously the number of bearing-places may vary according for example, to the length of the machine. Ribs s of similar nature to the reinforcing ribs 8 just described are also seen applied to one of the vanes d in Figure 1, so as to indicate that such ribs are applicable to all constructions of machines made ac cording to the invention. I

In any of the constructions, the slots of the rotor or the hearing or trunnion blocks may be fitted with anti-friction or bearing liners of white metal or other suitable material, where the blades take the bearing in the slots.

As the invention is not concerned with means for controlling the relative'movements of the blades, no devices have been shown for this purpose in the drawings. Obviously, however, the blades may be provided with feet or projections or slotted to form feet at the inner edge for engaging in grooves. of centric rings mounted anti-frictionally in the outer casing of the machine, or they may be fitted into rings or members revoluble anti-frictionally about a centric and fixed shaft in the casing of the machine all as will be understood without illustration by those acquainted with the art. In constructions where trunnion blocks are used, as in Figure 3, provision may be made for governing or controlling the position of the trunnion blocks to keep the slots in most favourable position with respect to the blades.

Lubrication of the bearing surfaces'niay be effected in any suitable manner. In conits II l

nection with Figure 1 ducts f in the rotor have been described for directly leading lubricant to the bearing surfaces 7, while in connection with Figure 6, mention has been made of the use of recesses o in the bearing or trunnion blocks is for facilitating lubrication of these parts indirectly by oil from the interior of the rotor. Other expedients may be adopted however, and as an example direct lubrication may be eflected by leading oil through passages in the bearing or trunnion blocks to the bearing places.

What I claim is:

1. A rotary pump machine comprising an outer casing, a piston body or rotor mounted eccentrically in said casing and having longitudinal slots or recesses with side walls Which are recessed or cut away slightly at parts of their length to provide rigid flat projecting parts and slightly sunken clearance parts eX- tending to the outer edges of the slots, and relatively slidable piston vanes fitted in said slots or recesses and adapted to take bearing on said rigid flat projecting parts over part of their length While having just a slight clearance, at said clearance parts, over the remainder of their length.

2. A rotary pump machine comprising an outer casing, a piston body or rotor mounted eccentrically in said casing and having longitudinal slots or recesses with side walls which are recessed or cut away part-circularly from the outside of the rotor in a manner to provide rigid flat projecting parts on either side of sunken clearance parts, and relatively slidable piston vanes fitted in said slots or recesses and adapted to take bearing on said rigid flat projecting parts over the part of their area while having just a slight clearance, at said clearance parts, over the remainder of their area.

3. In a rotary pump machine of crescentchamber type, a piston body and a piston vane in the form of a thin blade having relative sliding movement in saidpiston body, the contiguous engaging surfaces of these parts comprising one or more rigid bearing projections formed on and of shorter length than one of the parts and surfaces lying in a common plane or planes on the other part, and reinforcing ribs on said piston vane having a slight clearance in said piston body.

4. In a rotary pump machine of the crescent chamber type, a piston body with a relatively fixed longitudinal slot and a piston vane having relative sliding movement in said slot, contiguous opposed surfaces of the vane and slot parts being on one of these parts a plane surface and comprising on the other part a rigid projection adapted to bear on said plane surface, and the piston body having a lubricant duct leading directly to an outlet in said slot in the space opposite said projection.

GEORGE EDWARD THOMAS EYSTON.

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