The present invention provides a data processing apparatus and method for performing aligned access operations. In use of the peristaltic pump unit, a flexible resilient tube forming part of a medical fluid delivery line is extended between the peristaltic assembly and the counter surface or anvil provided by the door. The cover panels of the manway have upturned flanges formed along the lateral margins of the cover. The compressible valve may be disposed within at least a portion of the internal cavity and be movably retained within the housing.