Abstract: A cascade refrigeration system is provided. The cascade refrigeration system includes a low stage having a first refrigerant flowing therethrough and a high stage having a second refrigerant flowing therethrough. The low stage includes a compressor and evaporator coils. The input of the evaporator coils is operatively connected to the output of the compressor by an input conduit and the output of the operator unit is operatively connected to the input of the compressor by an output conduit. A bypass line has an input in communication with the input conduit and an output in combination with the output conduit. A bypass heat exchanger effectuates the heat exchange relationship between the first refrigerant flowing through the bypass line and the first refrigerant flowing through the input conduit.

Abstract: A composite magnet having a steel back plate on which an inner section of a first magnetic material having a high residual magnetic strength and an energy product greater than 25 million and preferably 35 million G-Oe or greater is positioned. Although possessing such high residual magnetic strength, the first magnetic material contained in the inner section comprises less than 1/8 the entire volume of the composite magnet. A barrier surrounds the inner section, and an outer section of a second magnetic material abuts the barrier and surrounds the sides of the first magnetic material. Such second section of magnetic material has a low residual magnetic strength (i.e., 3,800-4,000 G), and an energy product greater than 3 million G-Oe.

Abstract: The new method is particularly useful for inventorying frozen laboratory specimens such as found in a hospital or research center. The method includes placing a specimen at a primary location in a freezer, selecting an "identifier" unique to that specimen and displaying a symbol representing the primary location. More typically, both the storage system and the number of specimens are quite large and progressively-more-specific secondary, tertiary and even sub-tertiary locations will also be displayed. Removing the specimen from the compartment involves manipulating the freezer interface device, e.g., keypad and screen, to display at least the primary location. The user may manipulate by "scrolling" the screen or by entering certain specimen-identifying parameters such as a specimen description, the date of initial storage and others. An optional security arrangement can be incorporated and requires that persons attempting to place or remove a specimen must enter a personal identification number (PIN).

Abstract: Disclosed is a load carrier for use with a test chamber. Such carrier includes (a) an insertion portion having a length about equal to the thickness of a chamber wall, (b) a carrier portion extending away from the chamber and (c) a flange interposed between the portions for sealing contact with the wall. The insertion portion extends through an opening in a chamber wall to connect to a rack holding printed circuit boards. The carrier portion holds a test device connected to the circuit boards through the load carrier. The load carrier is removable and can operate in "standalone" fashion or be tested at a location remote from the chamber when another load carrier is substituted in the chamber. Chamber backplane wiring is eliminated or substantially eliminated.

Abstract: Disclosed is a particle sensor having a light beam with a beam long axis and an air flow tube with an inlet end and a particle exit mouth. In an aspect of the invention, the cross-sectional area of the flow passage at the inlet end is greater than the cross-sectional area of the exit mouth. This enlarged area dramatically reduces pressure drop along the tube. The exit mouth is in registry with the light beam and is elongate in a direction substantially parallel to the beam long axis. Thus, particles flowing through the mouth pass through the beam. In another aspect, the invention includes a centrifugal blower which is light in weight and which may be battery powered.

Abstract: The disclosure relates to an electromagnetic brake mounted to and used with electric motors. Such brakes have an "E" shaped electromagnet mounted on a magnet support. An armature block is mounted on a plate and both the block and the plate move when the electromagnet is energized or de-energized. The improvement involves a magnet support of the cantilever type. Such support bends slightly when the electromagnet is energized so that the faces of the "E" magnet legs can self-align and be maintained substantially parallel with the armature block. The preferred structure also includes a resilient pad interposed between the block and the plate and at least one stop limiting compression of the pad. A special bolt securing plate hold the armature block bolts in place.

Abstract: The disclosure involves a method for defrosting an inner door of a laboratory freezer having (a) a plurality of inner doors, each closing a separate compartment, and (b) an outer door covering the inner doors. The method includes the steps of opening the outer door, removing at least one inner door, closing the outer door and defrosting the removed inner door. In that way, an inner door is defrosted without disturbing the contents of the freezer and, particularly, the contents of the compartment from which the door is removed. Optionally, the freezer user may keep a spare inner compartment door on hand and use it to immediately replace the removed door before closing the outer door. Door defrosting steps and a new hinge mechanism facilitating quick door removal are also disclosed.

Abstract: The improved self-cleaning magnetic separator includes a tube and a conveying flight spiralled about the tube. The separator has a magnetic material collecting portion, a magnetic material discharge portion and a bar-like magnet providing a lobe-like magnetic field. The field is of generally uniform strength along the material collecting portion and diminishes in strength along the discharge portion. In a highly preferred arrangement, the magnet is stationary and the tube and flight rotate with respect to it. Because the magnetic material is "trapped" by the stationary field, such rotation causes the magnetic material to be urged by the flight from the collecting portion to the discharge portion. The field, of diminished strength in the discharge portion, permits magnetic material to fall away from the discharge portion.

Abstract: A cascade refrigeration system is provided. The cascade refrigeration system includes a low stage having a first refrigerant flowing therethrough and a high stage having a second refrigerant flowing therethrough. The low stage includes a compressor and evaporator coils. The input of the evaporator coils is operatively connected to the output of the compressor by an input conduit and the output of the operator unit is operatively connected to the input of the compressor by an output conduit. A bypass line has an input in communication with the input conduit and an output in combination with the output conduit. A bypass heat exchanger effectuates the heat exchange relationship between the first refrigerant flowing through the bypass line and the first refrigerant flowing through the input conduit.