Progressive Cavity Pumps Proven for Pumping Pre-Dough

Contributed by: PumpScout Staff

Selecting the right pump for industrial-scale dough operations can be a daunting task. As an integral piece of the mixing system, there are several standards a pump must meet to accurately, efficiently and uniformly mix pre-dough and starters. Many companies rely on outside organizations to design and configure a system, pump and all, for their baking operations.

IsernHäger is one such organization, specializing in pre-dough and sourdough systems for clients in the baking industry. The German-based company knows several pieces of equipment must work together for the successful operation of these systems, from containers, stirrers and controls to pumps and mixers. They provide high quality systems for their clients, which range from industrial scale operations to craft producers.

In 2011, one of IsernHäger’s clients required an all-in-one custom-configurable industrial installation with a fully automated production control system. IsernHäger has stringent requirements for the equipment included in its systems. As such, the company required a specific pump type and pump brand for their client’s project.

The Proof is in the Pump

The pump is an integral part of any pre-dough system; it is used to mix the pre-dough (essentially water) with flour. There are several criteria a pump must meet to be used in this system. After contacting pump manufacturer KNOLL Maschinenbau, IsernHäger decided to use a special version of KNOLL’s MX 30 progressing cavity pump.

Progressive Cavity Pump

Progressive cavity pumps are known for their ability to handle difficult liquids containing solids and highly viscous liquids. Also known as a single screw pump, the progressive cavity pump operates using a single threaded screw or rotor rotating inside a double threaded rubber stator to move liquid through the system.

Innovative Features for Custom Design

The specific pump model that IsernHäger selected features innovative technology that sets it apart from conventional designs. Knoll’s MX30 progressive cavity pump is fitted with EvenWall® technology, which means that the stator lining is adapted to the contours of the rotor and coated in a layer of elastomer with an even wall thickness. Traditional progressive cavity pumps have variable wall thickness because of the cylindrical stator lining.

There are many advantages to selecting a pump with EvenWall technology. Consistent wall thickness of the elastomer ensures greater stability under pressure, less backflow, longer pump life, higher efficiency, less product shearing and enhanced suction performance. Additionally, Knoll’s MX progressive cavity pump can operate effectively to pressure of at least 145 PSI with its chamber closed, compared to the limited pressure ranges of conventional progressive cavity pumps of between 58 and 87 PSI.

The Way It Works

The basic MX progressive cavity pump was altered slightly to fit this customer’s unique application for mixing dough. Reiner Völksen, of MX/KTSV Pump Sales at KNOLL, explains: "We have equipped this progressing cavity pump with a suction housing with a relatively large diameter and fitted the cleaning connections used for the CIP process with nozzles so that they can also be used for feeding fresh water."

Initially, the pump is filled hallway with fresh water via the aforementioned inlet, then the flour is added via the mouth. The pump quickly and efficiently mixes the two ingredients until the starter dough is fully incorporated. A large feed screw inside the pump provides the overfeed required by the pump assembly, making it possible do all the mixing inside the housing. After one to two minutes, the starter dough is complete and moves out of the pump.

Following the mixing and pumping process, the nozzles are used for cleaning. They are centrally located; every trace of residue is quickly cleaned without dismantling and the pump is ready for the next batch. These clean-in-place (CIP) and sterilize-in-place (SIP) features are standard for food manufacturing equipment.

Strict regulations around the food industry require food manufacturing equipment to comply with all hygiene requirements. These include that the design be virtually pocket free and that all metal parts in contact with the product be made of stainless steel. The material of construction also increases the system’s resistance to corrosion, temperature, and chemicals. The Knoll MX pump meets all the above requirements, satisfying the guidelines detailed in EHEDG, QHD, GPM and 3-A.

The customer was immensely happy with the system delivered and has since purchased and installed seven more such systems.


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