HCCL-Series Heater / Cooler / Classifier

Mechanical Components

The HCCL-Series classifier is constructed from four major components:

1. A base, or plenum chamber, into which fluidizing air is supplied by a blower.
2. A fluidizing deck
3. A heat exchanger bundle.
4. A main body, which serves as a cover and pressure chamber

The plenum chamber serves not only as a base, but also a means of distributing the incoming air to the underside of the fluidizing deck. The deck is an abrasion resistant steel plate containing self-cleaning orifices through which the air is passed through in order to fluidize the sand resting on it. The fluidization orifices are covered with abrasion strips which prevent sand from falling into the plenum. The fluidization action brings each grain of sand in intimate contact with the heat exchange bundle, which is mounted on top of the fluidizing deck and is made up of steel tubing mounted in close proximity between two water manifolds. The main body is mounted on top of the base (plenum chamber) and over the heat exchanger bundle. It serves not only as a cover, but also as a heating and classifying chamber.

The fluidizing action of the sand not only contributes to heating and cooling, but also polishes each grain, removing the dust and fines that exist naturally in the sand source as well as those created in the transportation of the sand to the HCCL. A negative pressure maintained over the bed by a dust collector (supplied by the customer or as an option) and controlled by a dam gate located between the dust collector and the heater/cooler/classifier ensures that all the dust and fines are removed from the chamber and around the sand grains.

Fluidizing air is provided by a constant pressure blower driven by a TEFC motor that includes an inlet damper control. Inspection and cleaning panels, flanged discharge, dust collection, and air manifold connections are included. The fluidizing air blower can be mounted on either side of the heater/classifier to suit the customer’s layout.

Sand throughput is regulated using a high quality butterfly style inlet valve. This valve actuates at the initiation of the cycle to meter sand into the unit. The concept of fluidization imparts that for every pound of sand poured into the unit, one pound will come out. The purpose of this valve is not only to meter the sand, but also to shut off the sand supply at the end of the cycle. This ensures that the classifier body does not pack full, maintaining consistent fluidization pressures and rates.

Heating water is supplied to the heat exchanger from a natural gas hot water boiler, unless otherwise specified. The boiler coupled with standard high resolution Honeywell temperature controller ensure constant exit temperatures even on the coolest day. An atmospheric hot water natural gas heating boiler is supplied as standard equipment.

Cooling water as standard would be supplied from city or natural well water. However, the system is easily adapted to include cooling tower or chiller controls. Temperature in cooling mode is controlled by the same Honeywell controller as is used for heating, simplifying controls and operation.

Controls

The standard control system includes all components necessary for the operation of this unit. All primary operating components are Allen-Bradley, the control transformer is ACME, and the temperature controller is Honeywell. These components are all off-the-shelf and available from high quality industrial and electrical supply houses.

A modulating valve, included as standard, regulates the flow of either cooling or heating water to the unit. This regulation is controlled automatically using a PID control loop. The closer the sand is to the desired process temperature, the less water will flow through the heat exchange bundle. The heating system is closed loop as standard. The cooling system, if using city water is either sent to drain or to cooling tanks. With the optional cooling tower or chiller package, the cooling loop is closed as well, minimizing water consumption year round.

The unit comes standard with all control logic necessary for the automatic switching from heating to cooling.

Hardware for this (electrically actuated diverter valves) is optional. Generally, all system valving and piping to the unit is customer supplied as all shops have different preferences for brand, type, routings, etc.

A rotary style level indicator controls the operation of the unit. Located in the discharge hopper, the HCCL seeks to maintain a full state. A run time timer initiates when the level indicator is clear. This insures that a certain surge capacity is always available.