Abstract: Disclosed is a two station system for a flow cytometer that includes a sample station and a wash station. During washing, the user has access to the sample station to insert a new sample. This increases the efficiency of the workflow process. Rotary clamps are used to automatically clamp the sample station and wash station to the system. A low volume pressurized cavity is used to bring the pressure of the sample to a desired pressure, which further increases productivity of the system. A transparent body is provided in the sample station so a user can view the sample during the sampling process. A backwash process is used to clean the sample injection tube and the sample uptake tube. In addition, the wash station is designed to rinse the outer surface of the sample uptake tube.

Abstract: Disclosed is a nozzle assembly that is compact in size and that uses plastic tubing as an injection needle. Standard plastic fittings are utilized, which are inexpensive and widely available. The nozzle assembly has a simple construction and can be easily assembled and disassembled in a few minutes by a user. Cleaning and/or replacement of parts is inexpensive. Plastic tubing can be used as an injection needle that has superior qualities over commonly used stainless steel injection needles. Flexure of the injection needle tubing is prevented because of the compact size of the nozzle cavity.

Abstract: Disclosed is an automated method and apparatus for automatically setting a drop delay period by detecting calibration particles in a waste stream. The drop delay is incremented over a series of drop delays and the number of calibration particles in the waste stream is detected for each drop delay. The drop delay is selected which has the least number of calibration particles in the waste stream.

Abstract: Disclosed is a sheath delivery system that uses a continuous flow of sheath fluid into a pressurized internal reservoir that substantially matches the outflow of sheath fluid through the nozzle of a flow cytometer. A substantially constant level of the sheath fluid is maintained. If the sheath fluid level falls below a desired level, or goes above a desired level, a dampened control system is used to reach the desired level. In addition, air pressure in the pressurized internal container is controlled so that an external sheath container can be removed and refilled with additional sheath fluid without stopping the sheath delivery system 100. Differences in pressure are detected by a droplet camera, which measures the droplet breakoff point to determine the pressure of the sheath fluid in the nozzle.