Help with Laboratory Centrifuges specifications:
Centrifuge Configuration
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| Configuration: | |||
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| Benchtop | The centrifuges are configured to sit on a lab bench. | ||
| Floor Standing | Floor standing centrifuges are larger floor models. | ||
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| Speed: | |||
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| Microfuge | Micro-centrifuges are made for spinning 1 to 2 ml plastic centrifuge tubes at speeds up to 12-or-13 thousand rounds per minute. They have very small, light rotors in them (the rotor is the part of the centrifuge that contains the holes for the sample tubes), which speed up and slow down rapidly. These centrifuges are very convenient for low-to-medium speed centrifugation of small quantities of material. | ||
| Super Speed | Super-speed centrifuges have speeds up to about 20,000 rpm and can take tubes of various sizes, depending on the rotors (the larger the rotor, the slower the maximum speed). Typical tubes hold 25-or-30 mls, but bottles as large as several hundred mls can be run with the correct rotor. | ||
| Ultracentrifuge | Speeds up to 70,000 rpm are available on typical modern versions of the ultracentrifuge. Again the size of tube and the maximum speed vary from rotor-to-rotor, but tube sizes up to about 60 mls are available. | ||
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| Analysis Method: | |||
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| Preparative | There are two types of preparative analysis: differential and density. The objective of this method is to isolate specific particles. Differential centrifugation is used to separate particles from a liquid medium or to separate particles of different masses into separate fractions of the supernatant. Density centrifugation works by spinning two fluids of different densities within a rotating container or rotor. The heavier fluid is forced to the wall at the inside of the rotor, while the lighter fluid is forced toward the center of the rotor. | ||
| Analytical | Analytical centrifugation involves measuring the physical properties of the sedimenting particles, such as sedimentation coefficient or molecular weight. Optimal methods are used in analytical ultra centrifugation. Molecules are observed by optical system during centrifugation to allow observation of macromolecules in solution as they move in gravitational field. The samples are centrifuged in cells (tubes with quartz windows) with windows that lie parallel to the plane of rotation of the rotor head. As the rotor turns, the images of the cell (proteins) are projected by an optical system on to film or a computer. The concentration of the solution at various points in the cell is determined by absorption of a light of the appropriate wavelength (Beer's law is followed). This can be accomplished either by measuring the degree of blackening of a photographic film, or by the pen deflection of the recorder of the scanning system and fed into a computer | ||
| Search Logic: | All products with ANY of the selected attributes will be returned as matches. Leaving all boxes unchecked will not limit the search criteria for this question; products with all attribute options will be returned as matches. | ||
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| Temperature Control: | |||
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| Heating | The centrifuge has an internal heating element. | ||
| Refrigerated | The centrifuge has an internal cooling mechanism. | ||
| None | The centrifuge is neither heated nor refrigerated. | ||
| Search Logic: | All products with ANY of the selected attributes will be returned as matches. Leaving all boxes unchecked will not limit the search criteria for this question; products with all attribute options will be returned as matches. | ||
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| Sample Introduction: | |||
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| Continuous | The centrifuge accepts a continuous flow of sample. | ||
| Batch | The centrifuge accepts a measured flow or volume of the sample. | ||
| Search Logic: | All products with ANY of the selected attributes will be returned as matches. Leaving all boxes unchecked will not limit the search criteria for this question; products with all attribute options will be returned as matches. | ||
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Rotor Configuration
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| Rotor Configuration: | |||
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| Zonal | In zonal centrifugation, the sample is applied in a thin zone at the top of the centrifuge tube on a density gradient. Under centrifugal force, the particles will begin sedimenting through the gradient in separate zones according to their size, shape, and density. The run must be terminated before any of the separated particles reach the bottom of the tube. | ||
| Fixed Angle | Fixed angle rotors vary from 20° to 45° from the axis of rotation. These rotors are used primarily for high-speed separations. The G-force is applied to the outer bottom edge of the tube, which is the farthest point from the rotor shaft. There are two types of fixed rotors, solid body and open body with shields. Samples requiring high G-forces, with a small amount of precipitate (requiring a tight pellet), or samples in filtration systems are good candidates for fixed angle rotor. | ||
| Vertical | The vertical rotors do the opposite of the swinging bucket; they use the shortest possible path of movement of the molecules. They are used when a very short overall path of centrifugation is required. | ||
| Horizontal / Swinging Bucket | Swinging bucket rotors rotate to a full horizontal position upon acceleration. The G-force is applied to the bottom of the tube. Liquids with more than one phase and samples requiring low to moderated G-forces are good candidates for swinging bucket rotors. Swinging bucket rotors (also known as horizontal rotors) have the advantage that there is usually a clean meniscus of minimum area. The materials must travel down the entire length of the centrifuge tube and through the media within the tube. Since the media is usually a viscous substance, the swinging bucket appears to have a lower relative centrifugal force that is it takes longer to precipitate anything contained within. | ||
| Drum | Drum rotors are specialized rotors for higher rotational speeds or higher centrifugal forces. The vessels (usually reaction vials) are held in cassettes and placed vertically into the rotor. The sedimentation method is similar to swing-bucket rotors. | ||
| Other | Other unlisted or proprietary rotor configuration. | ||
| Search Logic: | All products with ANY of the selected attributes will be returned as matches. Leaving all boxes unchecked will not limit the search criteria for this question; products with all attribute options will be returned as matches. | ||
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Performance Specifications
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| Maximum Speed: | The maximum speed that the rotor can attain. | ||
| Search Logic: | All matching products will have a value greater than or equal to the specified value. | ||
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| Maximum RCF: | Relative Centrifugal Force RCF = 1.12r (RPM/1000)^2 where r = radius in millimeters RPM = revolutions per minute | ||
| Search Logic: | All matching products will have a value greater than or equal to the specified value. | ||
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| Acceleration Time: | Acceleration time is the amount of time required for centrifuge to reach maximum speed. | ||
| Search Logic: | All matching products will have a value greater than or equal to the specified value. | ||
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| Timer Set Points: | Value of set points that the centrifuge accepts. | ||
| Search Logic: | User may specify either, both, or neither of the limits in a "From - To" range; when both are specified, matching products will cover entire range. Products returned as matches will meet all specified criteria. | ||
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| Rotor Capacity: | Number of samples the rotor will accept. | ||
| Search Logic: | User may specify either, both, or neither of the "At Least" and "No More Than" values. Products returned as matches will meet all specified criteria. | ||
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| Sample Volume: | Volume of sample tubes that will fit into the rotor. | ||
| Search Logic: | User may specify either, both, or neither of the "At Least" and "No More Than" values. Products returned as matches will meet all specified criteria. | ||
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User Interface Options
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| Local Interface: | |||
| Your choices are... | |||
| Analog Front Panel | The panel has analog user inputs such as potentiometers, dials, switches, for adjustment of output, ranges, etc. | ||
| Digital Front Panel | The panel uses digital keypads or menus for programming. | ||
| Search Logic: | All products with ANY of the selected attributes will be returned as matches. Leaving all boxes unchecked will not limit the search criteria for this question; products with all attribute options will be returned as matches. | ||
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| Computer Interface? | Can be controlled or monitored remotely with a computer via interface. | ||
| Search Logic: | "Required" and "Must Not Have" criteria limit returned matches as specified. Products with optional attributes will be returned for either choice. | ||
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| Computer Interface Options: | |||
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| Serial Interface | A port, or interface, that can be used for serial communication where only one bit is transferred at a time. Examples include RS232, RS422, RS485, USB etc. | ||
| Parallel Interface | A channel capable of transferring more than one bit at a simultaneously. Examples include PC Printer Port, Centronics etc. | ||
| Other Computer Interface | Modem, transmitter, TTL, etc. | ||
| Search Logic: | All products with ANY of the selected attributes will be returned as matches. Leaving all boxes unchecked will not limit the search criteria for this question; products with all attribute options will be returned as matches. | ||
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| Application Software Included? | For control or for monitoring the process. | ||
| Search Logic: | "Required" and "Must Not Have" criteria limit returned matches as specified. Products with optional attributes will be returned for either choice. | ||
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Display Options
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| Display Options: | |||
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| Analog Meter | Data is displayed with an analog meter or simple visual indicator. | ||
| Digital Readout | Device uses numerical or application-specific display. | ||
| Video Display | The data is presented in video form via CRT, LCD, or other multi-line forms. | ||
| None | No integral display. Output is read and displayed remotely. | ||
| Search Logic: | All products with ANY of the selected attributes will be returned as matches. Leaving all boxes unchecked will not limit the search criteria for this question; products with all attribute options will be returned as matches. | ||
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General Features and Functionality
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| Pulse Button? | Pulse buttons are used for short duration spins. | ||
| Search Logic: | "Required" and "Must Not Have" criteria limit returned matches as specified. Products with optional attributes will be returned for either choice. | ||
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| Removable Liner? | Removeable liners keep the centrifuge clean. | ||
| Search Logic: | "Required" and "Must Not Have" criteria limit returned matches as specified. Products with optional attributes will be returned for either choice. | ||
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| Imbalance Detection? | Imbalance detection alerts the user if the rotor is not balanced correctly. | ||
| Search Logic: | "Required" and "Must Not Have" criteria limit returned matches as specified. Products with optional attributes will be returned for either choice. | ||
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| Interchangeable Rotors? | Interchangeable rotors hold differing numbers of sample tubes. | ||
| Search Logic: | "Required" and "Must Not Have" criteria limit returned matches as specified. Products with optional attributes will be returned for either choice. | ||
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| Self-calibrating? | Is it necessary for the device to have a built-in calibrator to correct itself? | ||
| Search Logic: | "Required" and "Must Not Have" criteria limit returned matches as specified. Products with optional attributes will be returned for either choice. | ||
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| Data Storage Options? | Is it necessary for the device to be able to record and store data within its own memory, without transferring it to a separate data recorder? | ||
| Search Logic: | "Required" and "Must Not Have" criteria limit returned matches as specified. Products with optional attributes will be returned for either choice. | ||
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| Programmable? | The device must be programmable to provide for different ranges, materials, levels, outputs, etc. | ||
| Search Logic: | "Required" and "Must Not Have" criteria limit returned matches as specified. Products with optional attributes will be returned for either choice. | ||
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Environment
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| Operating Temperature: | This is the full required range of ambient operating temperature. | ||
| Search Logic: | User may specify either, both, or neither of the limits in a "From - To" range; when both are specified, matching products will cover entire range. Products returned as matches will meet all specified criteria. | ||
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