Ph.D.. Gulyj A. N.
Proceedings of the meeting industry chief engineers
Russian and CIS refineries and petrochemical plants.
m. Kirishi, 12-22 November 2002 m.
Over the past 40 s elastic plate clutch in the world replacing gear and bush-finger. Стандарт ISO / CD 13709 / API 610 It provides only an elastic compensating element type couplings for centrifugal pumps, chemical and oil refining industries. In the CIS in the past 5 years and it has expanded the use of the elastic plate clutches.
Causes – long service life of the couplings, no need of maintenance. But above all, – radical reduction of loads on the bearings connected machines. Consequently – increasing the operating time of bearing assemblies, mechanical seals, increasing the reliability and service life of the entire unit, which uses elastic plate clutch.
The elastic plate clutches torque transmitted through packages, It consists of plates of stainless steel ribbon thickness 0,2-1,0 mm. Form plates (rice. 1) – in the form of a disc, membrane (disk clutch), a ring (ring coupling). Usually two resilient package connected to the two coupling halves and the spacer by means of screws and plugs.
The annular clutch torque transmitted by stretching the compression-elastic element between the branches arranged alternately coupling halves fitting screw and the spacer. The disk – similarly, but half-coupling bolts and spacers are located on different diameters.
Each packet of elastic elements is also rigid in the radial direction and has a compliance of only angularly and axially. two pack, integrated spacer, can compensate for axial, angular and radial displacements (rice. 2). The flexible element of any type is rigid in torsion and not compensate for torsional oscillation shafts.
Coupling components are interconnected rigidly. Thus, coupling compensates for all kinds of displacement shafts to be connected solely by the elastic deformation of packages.
Compare similar in type 2 MW-toothed coupling transmit power and an elastic plate-type clutch MK2-210 (rice. 3) Compensation properties relative displacements of shafts.
- axial displacement. The torque is transmitted to the clutch gear by the forces, acting through the tooth contact. The sleeve 2 MW-transmitted torque at the rated total tangential (county) efforts will be about 30 000 n. With such a load for, coupling halves to move in the axial direction, necessary force of at least 3 000 n (friction coefficient – 0,1).
The elastic plate clutch prevents uncontrolled axial movement of the shaft in the freewheel and parking, because when there is axial displacement of the elastic restoring force, returning the shafts to the position, which is set during assembly. When the unit is properly installed thrust reaction sleeve and thrust load on the bearings of machines does not exceed 100 n.
- the friction force in the toothing, and hinder angular displacement, arising when misalignment. The coupling of MW-2, with nominal torque transmitted by the least angular displacement causes the moment of reaction in 280 Nm and a radial load on the shaft at least 2 000 n. Load increase as teeth wear.
The danger is not so much the quantity of possible radial load, transmitted to the supports, as cyclic, kind of impact load from slipping and collision of teeth is already at minimum misalignment.
Result – increased vibration and noise, wherein a rich harmonic spectrum.
The elastic plate clutch absorbs angular and radial displacements gently, without impacts and friction. Moreover, the reaction in magnitude and direction is constant, and causes only a small static load on the bearings. In our case, even at maximum misalignment in 0,50 mm, response time will not exceed 15 Nm, a radial load – 120 n.
- The gear coupling centering spacers relative to the coupling halves is achieved by planting a side surface of the teeth or centering girdle. In all cases, the centering surfaces are subject to wear, with gaps grow over time, increasing play and imbalance. The elastic coupling plate spacer is centered with the coupling halves of centering a belt or fit bolts mounting the clutch, Compound fitted by bolts, moving and wearing no connections. Therefore, during the operation or when replacing spacers balancing is not violated.
As a result, after the replacement gear couplings elastic plate vibration and noise are reduced in the centrifugal pump 30-50%, significantly increases bearing life and mechanical seals.
Features elastic mounting plate clutches are associated with limited permitted axial displacement. Upon initial installation is necessary to ensure the correct axial position of the coupling halves, wherein the elastic members are not deformed (i.e., stand distance L, rice. 4). For this purpose, the rotors with the motor and pump coupling half mounted in operating position (Engine with sliding bearings – on the label or on the results of the idle start, in pumps with hydraulic balancing device displace the rotor so, hydraulic balancing device to shut). Measure the distance between the motor shaft end and the end of the pump coupling half L1 (Figure 4).Is then calculated position of the motor coupling half and set it, fixing shaft. More often – attached to the spline by means of screws. Sometimes for adjusting the axial dimension of the coupling structure of the compensating element is introduced in the form of distance rings (rice. 4).
Another feature of the operation is associated with a small force of reaction on the shaft misalignments. when misalignment, several times higher than the maximum permitted, elastic plate clutch, not only do not cause excessive vibrations and noise, but do not allow to diagnose misalignment using equipment. Therefore, the alignment of the shafts of the unit should be periodically monitored by conventional mechanical means.
Danger arises fracture packets elastic members. first – opportunity “protection” massive enough spacers. Not all structures manufactured at the present time the elastic plate clutches available with redundant components, ensure the alignment of the coupling parts in the destruction of the elastic elements, as it referred to ISO / CD 13709 / API 610. Is separated from the driven machine spacer continues for some time to rotate with the motor shaft and presents a considerable danger for personnel, and for assembly.
Besides, fracture occurs elastic members collision or friction coupling parts. Therefore, for use in hazardous areas for those items, which may come into contact with the destruction of the elastic elements, You should apply materials, which collision does not lead to the formation of sparks (rice. 4). apply bronze, monel, nickel.
CLUTCH ENTERPRISE “NASOSTEHKOMPLEKT”
The company commercially produces elastic plate clutch within two type series – ring type and MC type disc MUE.
Climatic performance UHL2O4 couplings according to GOST 15150-69. Couplings in the “FROM” design allows for operation in hazardous areas of class B-1a and B-1g according “Regulation of electrical devices” categories and group IIA-explosive mixtures T3 according to GOST 12.1.011-78. Couplings meet ISO / CD 13709 / API standards 610 (8-revision) и API 671.
The couplings of both types of elastic elements are enclosed in packages node spacers, which understands only for their replacement (rice. 5). Spacer is centered on the girdle and the installation of the unit is connected to the coupling halves bolted (from 4 up to 8 pieces on each side). Rotation is transmitted by friction between the flanges and spacer coupling halves.
To cover a certain range of distances between the ends of the shafts are made of a number of spacer lengths in increments 40 mm and the distance rings are used. The precise fit of the axial dimension (to ± 0,5 mm) It carried installing and fixing the coupling half on the shaft by a screw or (usually, in the case of two conical shaft ends) fit for remote ring.
Couplings type MK – simpler in design, have smaller dimensions and weight, allow large overload torque, large shaft misalignment.
In the case of destruction of the elastic spacer element alignment and torque transmission continues special bushings, entering into contact with mating parts through the openings (rice. 6).
Structural coupling circuit type MK
|standard size||Transmitted torque, N * m||PREVENT-May-rate physicians scheniya,
kg in B min
|Permissible relative displacements of the shafts|
|MK 2-30||286||716||20 000||125||60||140||40||7||0,45||±2,8||0,5|
|MK 2-60||573||1 432||16 800||150||75||140||55||16||0,55||±3,2|
|MK 2-105||1 003||2 507||16 800||150||75||140||65||17||0,35||±2,0|
|MK 2-210||2 005||5 013||14 000||180||80||140||80||30||0,50||±2,2|
|MK 2-420||4 011||10 027||11 500||220||100||175||90||50||0,60||±3,0|
|MK 2-750||7 162||17 905||9 600||255||120||195||105||80||0,70||±3,8|
|MK 2-1200||11 459||28 648||8 500||285||140||205||120||103||0,75||±4,0|
clutch CBM disc type (rice. 7) available 8 years. The elastic element of these couplings is closed, and, in this way, protected from environmental influences. Such clutches are recommended if there is dust in the operation area, Vapor aggressive liquids.
Another important difference between the clutch – an instantaneous trip mechanism driven by the engine at very substantial overload due to the destruction of the elastic element package. Thus, as the absence of thrust nodes in large electric motors, when the pump shaft is prevented jamming large breakage.
In those cases,, when standard couplings do not meet requirements, use special couplings. for example, couplings for small axial distances between the shafts. It may also be significantly increased allowable misalignment, reduced size and weight, increased permissible speed.
Structural coupling circuit type MUP
|standard size||Transmitted torque, N * m||allow-
|Permissible relative displacements of the shafts|
|Short time allowed-my-menny||A
|MUP 2-15||143||251||20 000||125||50||80||35||10||0,25||±1,5||0,5|
|MUP 2-30||286||501||16 000||150||70||110||40||21||0,30||±2,0|
|MUP 2-60||573||1 003||14 000||170||90||115||55||27||0,30||±2,2|
|MUP 2-100||955||1 671||12 500||190||100||120||65||33||0,35||±2,2|
|MUP 2-200||1 910||3 342||10 800||220||120||145||80||45||0,35||±2,2|
|MUP 2-450||4 297||7 520||9 000||265||145||170||90||65||0,40||±2,6|
|MUP 2-900||8 594||15 040||7 800||305||160||175||105||92||0,40||±2,6|
|MUP 2-1200||11 459||20 054||7 500||315||170||205||120||115||0,40||±2,8|
|MUP 2-2000||19 099||33 423||6 500||360||180||230||140||145||0,45||±3,6|
|MUP 2-2600||24 828||43 449||6 100||390||195||240||160||175||0,45||±4,0|
Standard warranty period for all joints – 2 year from date of shipment. The manufacturer guarantees the supply of spare parts and repairs couplings perform remediation after the warranty period based on contractual.