Dead Weight Hydraulic Pressure Filter Press
The dead weight filter press is used to analyze filtration behavior and wall cake building characteristics of drilling fluids and cement slurries. Their stability is based on fluid loss and may be determined by measuring and describing the filter cake.
The components of the dead weight hydraulic pressure filter press are: A mud cell assembly to hold the mud sample c/w a base cap and drain tube to discharge filtrate into a graduated cylinder, a stand and cell support as well as the dead weight hydraulic assembly that provides the necessary hydraulic pressure. The base cap holds an exchangeable mesh on which a 3½” (90 mm) sheet of filter paper can be placed. The cell is attached to the dead weight hydraulic pressure assembly by means of a sliding, quick-disconnect coupling and is closed at the bottom by a yoke and screw device. The filter press offers a filtration area of 7.1 ± 0.1 in² (4580 ± 60 mm²) recommended by the American Petroleum Institute (API).
To perform the test the cell of the filter press is filled with drilling mud or fresh concrete. The cell is closed with the base cap and connected to the dead weight assembly. The dead weight hydraulic pressure assembly has a U-shape. On one side of the U a vertically aligned cylinder with a piston acting on a water column can be found. A dead weight is resting on the piston, pushing the water into the other side of the U, thus creating the filtration pressure in the filter press’ cell. When the system is closed, the dead weight causes the piston to exert a continuous pressure of 100 PSI (6,895 bar) against the fluid inside the filter press cell. Filtrate is driven through filter paper and the outlet in the base cap and collected by means of a graduated measuring cylinder. After a time period of 30 minutes the amount of discharged fluid may be recorded and the filter cake that has formed on the filter paper is measured and described. The pressure on the cell is released promptly at completion of the test with a bleed-off valve.
The advantage of using a dead weight hydraulic assembly is that no pressure regulator, Co2 cartridges or outside connections are needed to provide hydraulic pressure. All it takes to perform the test are approximately 17 oz (500 ml) of fresh water. In addition, the assembly requires only a minimum amount of maintenance.
MUDTEST filter press comply with the requirements of API RP 13B-1 or the corresponding international standard ISO 10414 for field testing of drilling fluids. The requirements of the German standard DIN 4127 for the test procedure for supporting fluids in diaphragm wall construction are also met. The filter press falls within the scope of the European Pressure Equipment Directive 2014/68 / EU. Therefore, the corresponding conformity assessment procedure was carried out and the CE marking was attached.
