PENN STATE UNIVERSITY

DEPARTMENT OF MECHANICAL ENGINEERING

ME 414W SENIOR DESIGN PROJECT

Members:

• Brian Russo             Project Manager

• Chris Fluck             Assistant Project Manager

• Jeremy Fahr            Secretary     

• Chad Bowser          Meeting Facilitator

• Jon Rose                 Research Analyst

Project Title: 

    Design and Construction of a Laboratory-Scale Spray Chilling Unit

Overview:

    Spray-chilling is a process by which fat-based food ingredients can be heated above their melting point, mixed to create proprietary blends with unique functional properties, and then atomized into a stream of chilled air which causes the atomized droplets to solidify.  The spray-chilled blend can then be packaged and sold to food manufactures as a free-flowing powder.  Industrial-scale spray-chilled ingredient blends are used in formulating ice cream, whipping cream, and bakery products, among others.  The process by which new products are introduced to this system would be greatly facilitated by the ability to model the process on a laboratory scale.  The goal of the proposed project is to design and construct a small scale version of an existing industrial spray-chilling tower at our sponsor's location.

Objectives:

The main objective of this project was to design and construct a proof-of-concept prototype of a small spray-chilling system with the following attributes:

• Construct a vertical configuration, with heated product atomized at the top of a chamber into a stream of air.  The chilled particles would then drop to the bottom and then be collected.
• Construct a temperature-controlled vessel for holding and melting the raw product before introduced into the cooling chamber.
• Develop a Pump suitable to transfer the liquid from the container to the atomizing device at a desired pressure.
• Develop an atomizing method to obtain the nominal particle size specified.

The cooling chamber that our sponsor has asked us to model on laboratory scale can be seen below.  The tower extends four stories tall.  

Figure 1: Full Scale Spray Chiller

Our Design: (The design information can not be specific do to confidentiality requirements of the sponsor) 

    The first task that our group considered was the  atomization of the emulsifying fluid.  We decided that a atomizing nozzle should be used because of the limitations on the cooling time, and actual size of the model.  Once a nozzle was decided upon, the next task was to develop at method to pump the fluid at the required pressure.  We decided on a Peristaltic Pump, so the fluid did not have to come in contact with the pump parts lowering both cost and maintenance.  After laboratory testing we concluded that the fluid would atomize after being sprayed through the nozzle without any other means of cooling.  The only design factors in building the cooling chamber were its height, diameter and material properties.

Our design can be seen in the pictures below.

Figure 2: Drawing of Frame and Assembly

Figure 3: Frame with Pump and Heating Unit

Figure 4: Nozzles and Fittings

Figure 5: Heating Unit, Thermometer, and Stainless Steel Measuring Container