High Cooling Surface to Volume Ratio
Provides excellent cooling control with low water temperature differential which minimizes possibility of false grain formation.
*All Models of 11 Foot Diameter
Promotes plug flow for best heat transfer. Ships by truck and minimizes installation area. Fits inside many factories but also works well installed outside.
*Stationary Cooling Surfaces
Provides large area interconnected on vessel exterior for convenience and flexability. Can cool and heat in same body. Excludes troublesome rotary joints.
*Simple Hydraulic Piston Drive
Agitator /wiper arms moved efficiently with inherent overload protection. No gears to cause problems. All cooling surfaces wiped every two minutes.
*Versatile Process Design
Up flow or down flow work equally as well. Can be added to existing crystallizers as first or last unit or used in multiples. Tall design provides head for flow to following vessels. *Rugged Machinery Design
Drive has high torque rating for the heaviest rnassecuites. All parts of generous thickness. Requires a minimum of rnaintenance.
The following is a specification describing the Silver Weibull USA Continuous Vertical Crystallizer vessel.
Description:
The Silver Weibull Continuous Vertical Crystallizer is a cylindrical vessel with a vertical axis. The vessel is 11 feet-0 inches inside diameter and varies in height depending on the volume required.
Each heat exchange element consists of a serpentine arrangement of 3 inch diameter (Schedule 40) pipe located in a horizontal plane. These elements are positioned on 2 feet vertical centers throughout the height of the crystallizer providing a surface to volume ratio of approximately 0.5Ft2 /Ft3 (1.64 M2 /M3 ).
The pipes forming each heat exchange element extend to near the inner wall and then return 180 degrees to near the opposite wall forming the serpentine. Each level is connected externally to the preceding and following level to provide correct countercurrent flow of cooling water to material flow.
The crystallizer is composed of one top and one bottom section, 95-3/8 inches high, and several (depending on the model) intermediate sections, each 95 inches high. The top and bottom sections each contain three heat exchange elements and the intermediate sections each contain four elements. These sections are prepared for field erection of the crystallizer vessel assembly. All sections are fabricated from 3/8 inch thick carbon steel plate. The top and bottom sections are each equipped with a 12 inch pipe stub for massecuite inlet and outlet and 3 inch flanged pipe nozzles for the cooling water connections. There is an 18 inch diameter manhole in each section. The outside of the vessel is given a coat of red oxide primer prior to shipment.
The vessel is equipped with a heavy wall, tubular shaft extending throughout its entire height. Two scraper arms are attached to this shaft between each pair of heat exchanger elements in such a manner that one arm cleans the bottom surface of the upper element and the other arm cleans the top surface of the lower element. The arms are fabricated of 4 inch diameter (Schedule 80) pipe and 3/8 inch thick carbon steel bars. For the bottom feed arrangement, the massecuite is fed into the bottom of the shaft and then distributed across the bottom of the crystallizer through the two bottom arms equipped with properly sized discharge openings.
The shaft is driven by a hydraulically actuated, ratchet type drive consisting primarily of a hydraulic power unit and a hydraulic cylinder which pushes a toothed ratchet wheel. This drive produces a rotary motion with an average speed of 0.5 RPM. The motion is discontinuous. (Two cylinder continuous motion is available) .
The power unit for this drive consists primarily of an electric motor driven hydraulic pump, an oil reservoir with filter, cooler and gauges and is a complete unit mounted on a base and ready for field installation. A space for an auxilliary pump and motor can be furnished if requested with order. The auxilliary pump and motor may be ordered as spare parts at a later time.
The radial load from the ratchet drive and the vertical load of the shaft assembly are carried by grease lubricated, bronze bearings in a bearing assembly located at the drive end of the shaft. The bottom end of the shaft is restrained from radial movement by a socket type bearing submerged in, and lubricated by, the massecuite.
Shipment:
The crystallizer shell is fabricated for shipment in several intermediate sections and a top and a bottom section. The shaft is shipped in two or three sections with a male/female joint for field assembly by welding. The scraper arms which attach to the shaft, the water pipes which connect between sections, and the ratchet drive components are shipped loose for field assembly. The power unit for the drive is shipped as one complete assembly ready for field connection to the drive.
Optionally, the unit may be more or less assembled.