The central forces of a centrifugal pump is the result of the pressure difference at the front and rear wheels. In most cases, this force is directed towards the suction pump. There are cases where the application of the high pressure power steering suction hub away from the suction side of the pump.
There are several ways to balance the power of the pump. The most easiest way is to use hard or angular contact ball bearing. Obviously, this method has some limitations, such as the size of the central power, so the size of the bear, its heat and long service life. The second way is to use the impeller with double suction, which is essentially balanced axial force due to the geometric symmetry and hydraulic.
In theory, in this case-the angular contact bearings are not necessary, but there are actually a small residual payment, as evidenced by small differences in the geometry of the impeller, cochlea landmarks, cross-flow systems and installation of suction pipe. In fact, it may be useful to create a certain amount of axial load on the pump to achieve stability in the rotor. Another way-using defenses against on the same shaft. This creates a strong opposition to Central balance reduces the effectiveness or eliminates this burden. The simplest example is a two-stage pump with horizontal split casing, which are arranged opposite defenses. She said further steps, the design of the pump becomes more difficult.
Normally be completed a series of defenses in one direction and then in the opposite cross feed chain within the body casting, or mounted externally on the pipe through. You can set a series of double-suction impellers, but will increase the size and complexity of the casting, become impractical when using more than two steps. Take advantage of these methods is the lack of an additional pressure loss in hydraulic head balance mechanism. There are leaks through holes of a ring and the sleeve, but it doesn’t matter to the hydrostatic balance. There are other ways to balance the axle hydraulic forces.
The impeller can be mounted with balancing holes. This reduces the pressure on the pressure on the impeller, and linking the region to the suction side of the blade space with impeller. This stream is fed from the rear forward impeller. This reduces the efficiency of the pump to the suction capacity is longer than the full port flow. Furthermore, the holes do not require fully balance loads focal. The full amount is increased for the current basket, with the number of stages, which makes this a problematic approach to multi-stage pumps. During multistage high-pressure pumps with impeller and diffuser respectively you can often find the use of drum or disc weighing balance.
Both use high pressure drop and balance the line connecting the suction and discharge side of the pump. They differ in the direction of flow is discharged: perpendicular to the shaft-in case your balance and parallel to the shaft of the pump-in balance a barrel. Another difference is that the disk works balance and pit with variable cross section, drum balancing, and pit of constant cross-section, and balance the flow bypass bypass line from discharge to suction. In both cases, the pump Chamber is connected to the back of the TomTom disk or balancing along the suction of the pump, called the line of balance.
So-called reverse flow through the line balancing flow. Low-flow, balance and more efficient pump, because in the same energy input into the system gets more of the liquid being pumped. Disk eliminates the need to balance the loaded batch, because the gap between the rotating and stationary balancing disk surfaces varies with pressure head. Due to the increase in pressure head and axial forces on the rotor, the rotor will grow towards the suction side. The regular budget portion of the disk that is fixed to the shaft-forward, reducing the clearance between it and the part of the disk. As a result, the pressure in the Chamber between the rotating and fixed parts of the disc increases budget, pushing the rotor of the pump suction side, eventually, in a stable.
This means that there is some movement of the spear, and as a result-the change in pressure, but thanks to the excellent balanced rotor and balance your balance is less than the flow and its application will be the most effective way to balance the load on multiple stages with hydraulic pump impellers arranged in a row. However, there is a possibility of contact during startup and operating in conditions of transient, which may cause damage. Study of reliability boiler feed pumps that most interruptions can be associated with the use of your budget.
The disk does not allow balance in these types of pumps for similar reasons. Basically, drum balancing sleeve with a small clearance (rotor balancing drum mounted on the shaft) in the fixed part (fixed to the cylinder, and is attached to the body). And the balance of about 85%-90% of the central powers were and will continue to effect the required momentum. Pressure drop-function of radial clearance and the length of the barrel, it will determine the flow balancing. There is no movement of the rotor in response to changes in pressure, moreover, may have the effect of orientation.
This simple device has no operating modes, where there may be a connection. The hydraulic balance is based on the calculation of area of the cross section of the cylinder so that the power balance will increase or decrease with the discharge pressure, but since the balance of force is not the self, such as the central force remains free disk, which will be in batch loader.