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Belt or Gear Drive for Crude Oil (BS&W)

Product Type:
Mixers And Blenders / Side Entry Mixers

Plenty swivel angle mixers for tank cleaning operations and the prevention of harmful sludge settling.



  • Over 30 year's operational experience specifically developing and utilizing swivel angle mixing technology
  • Identical rugged, heavy duty design as for fixed angle mixers to extend service life
  • Minimum maintenance requirements
  • Gear or belt drive options (see Models tab)
  • Mechanical seal is standard supply
  • Manufactured on modern computer controlled machining centers
  • Optional automatic actuators available to negate need for manual swivel angle change
  • CE & ATEX 2G certification available

Unique Tank Shut-Off Device

All units incorporate a tank shut-off device to allow the shaft seal and bearings to be changed under full tank conditions. The tank shut-off mechanism incorporates tapered metal to metal faces, positively clamped by a bolted flange which both seals products in the tank and securely supports the shaft during bearing and/or shaft seal changes.

All tapered faces are wear and corrosion resistant. The most important aspect of the Plenty Shut-off and mechanical seal assembly is that it incorporates a safety check valve for ensuring that the shut-off is 100% effective before removal of any bearings or the mechanical seal. The Plenty shut-off mechanism offers complete safety and security as it does not incorporate any flexible O rings or gaskets which may deform, wear, or perish.

Key Applications

Crude Oil, Bottom Sludge and Water (BS&W)


In most crude oils there are varying quantities of Bottom Sludge and Water (BS&W) which contains paraffins, heavy ends, sediments of sand / silts and water. The rate of accumulation varies with the quality of the crude stored.

Swivel Angle mixers incorporate a feature which allows the mixer angle of entry to be varied through 30° either side of the tank centerline in 10° increments and enables the entire tank floor to be directly scoured by the impeller flow stream. This is the only satisfactory solution to BS& W control in large tanks and ensures that the heavy solids, water and corrosive salts which settle in areas least agitated by a permanently fixed mixer are maintained in suspension.

Some of the main reasons why BS&W should be controlled are:

  • Tankage is always available for storage and not out of commission being cleaned or repaired
  • Problems of sludge disposal are overcome.
  • Accumulation of BS&W can cause severe corrosion of tank floor and lower shell plates.
  • Hazardous, dangerous and costly tank cleaning is practically eliminated.
  • Large accumulations of BS&W can dramatically reduce ‘operations’ flexibility.
  • If slugs of BS&W break free during pump-down then serious damage to the transfer pumps or even disruption of the refinery operation can result.
  • Elimination of “plugged” water drains.


Combined Duties


It is possible that one or more of the duties may apply to a particular application and the most critical duty must determine the selection of mixer.

Swivel Mixers are capable of performing the same duties as a fixed angle mixer when fixed in the correct position.


Seal Leakage Detection

The Plenty standard seal leakage detection system provides an economical solution to alert the operator of leakage passed the mechanical seal. Any leakage is collected and contained within a collection vessel that is equipped with a level sensor that can activate an alarm in the control room.

Other leakage detection systems can be supplied to meet API Plan 65 and Plan 75 if required.

The leakage system can be mounted to a fixed or a swivel angle mixer or can be mounted on the floor near to the mixer





As an alternative to this manual facility, an automatic swivel actuator can be supplied as an optional extra.

The Automatic Swivel Actuator is a shaft belt driven or an electric motor driven speed reducer and linkage, which allows the mixer to swivel 30 degrees in either direction.
Using the shaft driven actuator provides constant motion of the swivel while the mixer is in operation. This option removes the need for expensive additional field wiring.
With the electric motor driven actuator the timer controller provided will cycle every 24 hours and swivel the mixer 10 degrees each time.

The use of either swivel actuator allows for efficient cleaning of the tank bottom and eliminates the need for routine manual adjustment. Actuators are available for both gear and belt driven mixers.

Lightnin and Plenty Side Entry Mixing
Heavy Duty Side Entry Mixers - PLM-102 US GB
Leistungsstarke Horizontalruehrwerke DE

Gear Driven Mixer

Driven by a vertical electric motor which is flange mounted on the support bracket above the gearbox and connected by an all metal flexible coupling protected by a guard. The gearbox comprises a single reduction hardened high efficiency spiral bevel gear set having a minimum service factor of 1.5 and are designed to AGMA and DIN Standards. The gears and all bearings are splash oil lubricated and enclosed in a large gear case for maximum heat dissipation. The mixer frame is a rigid one-piece iron casting with spigot located on the gearbox and the steel mounting flange.

Gear driven mixers are available in both fixed angle and swivel angle models.