Lobe pump

Rotary lobe pumps are self- priming or conditionally, valveless, positive displacement pumps with interlocking running rotary piston. As they are manufactured vacuum pumps ( Roots Blower ) with non-contact rotors.

Function and structure

By rotation of the rotor pair is formed at the suction side, which is determined by the rotation direction of the drive, a negative pressure, whereby the pumped fluid is sucked up. The medium is delivered then pushed further through the rotor to the pump wall by at the print area. In one revolution of the drive are - depending on the type of the rotors - displaces from two to six chamber fills. When the rotors stop the pump pair closes almost completely. This applies to rubber rotors. Existence of the rotary piston made ​​of steel or stainless steel, these undersized to prevent corrosion. A complete seal is not possible with these therefore.

Safety chamber (quench )

Some rotary piston pumps have an intermediate chamber between the pump and gear housing. It is filled with a liquid, which performs several functions:

  • It acts as a safety chamber for the mechanical seal, displays of the mechanical seal leakage due to overflow at the filler opening and lubricates the connection between waves and rotors.
  • It prevents the penetration of the pumped medium in the timing gear.
  • In addition, a quench protection against dry running.

Variants

In addition to the straight piston in the pump chamber, there are also versions with coiled, non contacting rotors ( so-called spiral bulb), the triangular or trapezoidal chamber openings form precise sealing lines to the coiled rotors. With this variant, the pulsation of the pump is reduced, the fluid is less destroyed. The pistons may be sheathed with rubber. In order to obtain a self-priming pump, but is abrasive. This may result in contamination of the medium with piston wear.

The rotor can be provided with jaws; this results in a higher compression engine ungleichmäßigerem emissions ( claw pump ). The starting torque of rotary lobe pump is in its construction depends: if touching the rotary pistons each other, have contact with the housing or not.

In order to achieve an even better product protection, there is also sinusoidal helical rotors couples.

Funding area

A rotary pump promotes a function of the viscosity of the fluid flow rates of about 1 to 1250 m³ / h Claw pumps are available up to 300 m³ / h.

Characteristics of positive displacement pumps

  • Rotary lobe pumps are also suitable for media with high turbidity levels and work reliably even with fluctuating solids.
  • Different solids contents do not affect the flow rate and the amount of variation in the amount of solids caused by pressure changes are small.
  • Due to its large free ball passage and low pump speeds they are relatively insensitive to clogging, ragging and debris.
  • The rotary pump is self-priming and self-priming and requires their usually symmetrical design allows rotation direction and thus conveying direction reversal - a benefit that is especially used for the emptying of solids collectors.
  • A rotary piston pump can promote both low - and high-viscosity media. This allows them to be used as in the sugar industry for both expiration or molasses and front sight base or magma. This reduces the cost of spare parts inventory and training requirements.
  • The efficiency of rotary lobe pumps is higher than that of many other positive displacement pumps. This results in lower energy consumption than about when flaps pump and saves investment costs for drives and regulations (such as frequency ). Since the energy accounts for the largest share of the life cycle costs of a pump, this advantage is a key criterion in the selection of pump type.
  • Rotary lobe pumps are compact. The suction and discharge ports are in a line.
  • Rotary pistons have a stable pressure - volume curve: Even with an increase in the feed pressure is the volume flow back only slightly. For centrifugal pumps, however, the flow rate falls with increasing feed pressures rapidly.
  • Rotary piston pumps operate without interior compression as opposed to, for example, vane pumps. The isentropic efficiency is lower than in Inner compression.
  • There are designs on mobile base frame for mobile use.
Quench (disambiguation) Natural rubber
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