Designs for Large and Small Samples
These vessels are made in five different sizes to accommodate samples ranging from 0.5 mL to 5 liters. The maximum charging capacity for each vessel is limited to two-thirds of the internal volume of the vessel, but smaller samples can be treated in any of these vessels by simply placing the sample in a beaker or test tube and positioning it under the dip tube within the vessel.
Easy Access to Vessel Chamber
Each of these vessels, except the small 45 mL size, has a split-ring closure — an exclusive Parr design which allows the vessel to be opened or closed easily without disturbing any of the fittings or connecting lines attached to the head. In this closure two ring sections slide into place from the sides of the vessel to lock the head in position while a self-sealing O-ring maintains a tight seal at all pressures. The ring sections are secured by a steel retaining band that is raised from the bottom of the vessel and anchored with a single, hand-tightened screw.
On the small, 45 mL vessel, a firm closure is obtained by simply turning down a knurled cap until it is hand tight. No wrenches or fixtures are required.
Parr Cell Disruption Vessels are designed to exacting safety standards. Most models can accommodate the full 2000 psig available from a commercial nitrogen cylinder. If higher pressures should accidentally develop, the 920 mL and larger vessels are protected by a safety rupture disc which will burst at approximately 3000 psig, well below the pressure at which any parts of the vessel would fail. A 3000 psi pressure gage and a 3000 psig rupture disc are standard but other gages and discs with lower pressure ratings can be furnished on special order.
Most cell disruption procedures can be handled readily in the 920 mL, 4635 Vessel with its customary fittings and attachments, yet applications may arise in which it will be desirable to modify a vessel to meet special requirements. If initial studies show a need for modifications, the user can return any vessel to the factory for such changes or additions as may be needed. Changes sometimes requested include:
Multiple sample capacity.
Up to three additional dip tubes and discharge valves can be installed in any vessel (except the 45 mL size). With these additional outlets and appropriate sample holders, as many as four samples can be processed independently and simultaneously in a single unit.
Valves with either larger or smaller orifices can be provided. Users processing large quantities of materials that have a tendency to plug the orifice of the standard throttling valve may want to substitute either a larger needle valve or a ball valve to permit faster flow rates or to avoid stoppage. Fine metering valves with smaller orifices and very precise control capabilities may be helpful when treating samples that must be processed under very exact and repeatable conditions. Such valves may also be desirable when working with very small samples.
Since cylinders for the 920 and 1850 mL vessels are interchangeable and both vessels use the same head and closure, any user of a 4635 Vessel can increase the capacity of their unit to the 4636 size by simply purchasing a deeper cylinder (599HC22) and a longer dip tube (591HC5). A similar conversion can also be made from the one gallon vessel to the two gallon size for users interested in vaccine production or in similar large volume applications. These larger vessels can also be equipped with vigorous internal agitators to speed equilibrium times when processing large volumes of material.