The Model 4555 and 4557 Reactors have a 5 gallon (18.75 L) capacity while the 4556 and 4558 Models are similar units with a 10 liter (2.6 gal) volume. The 10 liter reactors fall between the larger 5 gallon design and the smaller 1 and 2 gallon models in the 4550 Series. Vessel styles are offered in a moveable head or fixed head design.
These reactors are available with an FKM O-ring seal for operating temperatures to 225 °C, and FFKM O-ring for temperatures to 300 °C, or with a flat, PTFE gasket for operating temperatures up to 350 °C maximum.
In the moveable head design (see page 46), the vessel is held in a support system which minimizes the physical effort required to handle these heavy components. The hoist is attached to a support column which provides a convenient means for lifting the head and cylinder out of the stand. These components may be transferred to the holding position on the right side of the stand. Vessels equipped with a bottom drain valve will probably remain in the heater most of the time, but can be lifted out when necessary.
The fixed head support stand features hinged split-rings that swing to either side allowing the head to remain fixed to the stand while a pneumatic lift allows the cylinder to be raised and lowered. When lowered, the cylinder can be slid forward for cleaning and servicing.
The Series 4555 reactors are generally used for pilot plant or for custom chemical production purposes, usually with a variety of attachments added to the basic units. Various heaters, larger motors, heavier stirrer drives and remote controls appropriate to the size of these reactors have been designed and are available. Modified versions of these units are available with higher working pressures and temperatures.