Rotary expansible chamber devices – Multistage
Patent
1987-03-20
1988-08-16
Vrablik, John J.
Rotary expansible chamber devices
Multistage
418 48, 418182, F01C 1107, F01C 1100, F03C 208
Patent
active
047640944
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The invention relates to power engineering and, more particularly, to screw machines.
PRIOR ART
Today, two basically different methods are used for drilling wells. The first one is a rotor method of drilling whereby the drive of a rock-breaking tool-bit is arranged on the surface and rotation to the bit is effected via a drill pipe string. The second method provides for the use of downhole motors as a drive which are disposed directly above the bit. The drill pipe string is stationary. The second method possesses a whole number of obvious advantages: no power is needed to rotate the drill pipe string, loads on drill pipes are diminished and, as a result, the number of failures in the borehole is decreased.
Among all types of downhole motors currently used in drilling wells, screw downhole motors are gaining a broad acceptance. These motors are simple to operate and service, have small overall dimensions, enable one to work with drilling muds of different density and viscosity (cf. M. T. Gusman, D. F. Baldenko et al. "Downhole Screw Motors for Drilling Wells", Nedra Publishers, Moscow, 1981).
In their typical design these motors contain a housing, an output shaft with radial and axial bearings and a screw mechanism which comprises a stator with internal screw teeth and a rotor disposed therein with external screw teeth. The stator is made in the form of a metal housing with an elastic lining vulcanized to its internal surface. In turn, the internal surface of the elastic lining has screw teeth. The number of the stator teeth exceeds by one that of the rotor teeth thereby ensuring, as the teeth interact, the division of the internal cavity of the screw mechanism into the working chambers--the cavities of high and low pressure. As the working agent is pumped through the screw mechanism, the working members begin to move relative to one another under the action of an arising pressure drop. In a typical most accepted design of the motor the stator is motionless and the rotor executes a planetary motion- the rotor axis describes a circumference around the stator axis and the rotor proper rotates about its own axis. This rotation is transmitted to the motor output shaft. By changing the number and the length of the pitch of screw teeth, one may obtain any necessary output characteristics of the motor. The latter is operated by the flow of the working agent which may be liquid (water or drilling mud), as well as aerated fluid or compressed air.
The major disadvantage of the aforelisted motors is a strong transverse vibration arising due to a specific motion of the screw mechanism rotor. Vibration causes a premature failure of the screw mechanism, the axial supports of the motor and may lead to a breakdown.
Also known in the art is a screw downhole motor, which comprises successively arranged screw mechanisms including coaxially disposed stators and rotors mounted therein whose axes are displaced relative to the axes of the stators to the value of eccentricity "e" of the screw mechanisms, as well as a spindle section (USSR Inventor's Certificate No. 286502, cl. F04 C5/00, 1969). This motor is basically the closest one to the present invention. In this design by way of calculations and selection of the lengths of coupling thread bushings, the axes of the rotors disposed in two adjacent stators of the screw mechanisms may be located in the same diameter to different sides from the axes of the stators. This assembly of the motor is fairly complicated and takes much time. Besides, an insignificant variation of the axial length of a group of rotors or stators with respect to each other upsets the position of the axes of the rotors relative to one another which is established during the assembly. A mere connection of one screw mechanism to another does not guarantee such an assembly. At the same time, the level of vibrations in the outlined construction does not decrease even in case of an optimal assembly because the forces of inertia and moments thereof affecting the motor are not balanced out.
DI
REFERENCES:
patent: 3999901 (1976-12-01), Tschirky
patent: 4011917 (1977-03-01), Tiraspolsky et al.
"Downhole Screw Motors for Drilling Wells", Gusman and Baldenko et al., Nedra Publishers, Moscow, 1981.
"Screw Drilling Motors", Drilling Series, Moscow, 1972.
Baldenko Dmitry F.
Gusman Moisei T.
Khabetskaya Valentina A.
Semenets Valery I.
Vadetsky Jury V.
Vrablik John J.
Vsesojuzny Nauchno-Issledovatelsky Institut Burovoi Tekhniki
Walnoha Leonard P.
LandOfFree
Screw machine having a plurality of symmetrically arranged rotor does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Screw machine having a plurality of symmetrically arranged rotor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Screw machine having a plurality of symmetrically arranged rotor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-597925