A positioning foot having a hydraulic shock absorber with a fluid-filled hollow cylinder (210), in which a piston (220) that moves axially between an advanced, spring prestressed position and a retracted position. The piston separates a front axial fluid space (214) and a rear axial fluid space (215) from one another in the hollow cylinder. Both fluid spaces are connected to one another in a fluid exchanging fashion via at least one throttle opening (223) in the piston. The piston is rigidly connected to a piston rod (221), which passes through the front fluid space and abuts a fixed stop (218) in the retracted position, in which the volume of the rear axial fluid space is minimized and the volume of the front axial fluid space is maximized. The spring prestress is dimensioned so that the weight of the device body moves the piston dampingly into the retracted position.

A positioning foot having a hydraulic shock absorber with a fluid-filled hollow cylinder (210), in which a piston (220) that moves axially between an advanced, spring prestressed position and a retracted position. The piston separates a front axial fluid space (214) and a rear axial fluid space (215) from one another in the hollow cylinder. Both fluid spaces are connected to one another in a fluid exchanging fashion via at least one throttle opening (223) in the piston. The piston is rigidly connected to a piston rod (221), which passes through the front fluid space and abuts a fixed stop (218) in the retracted position, in which the volume of the rear axial fluid space is minimized and the volume of the front axial fluid space is maximized. The spring prestress is dimensioned so that the weight of the device body moves the piston dampingly into the retracted position.

An improved method of deprotection in solid phase peptide synthesis is disclosed. In particular the deprotecting composition is added in high concentration and small volume to the mixture of the coupling solution, the growing peptide chain, and any excess activated acid from the preceding coupling cycle, and without any draining step between the coupling step of the previous cycle and the addition of the deprotection composition for the successive cycle. Thereafter, the ambient pressure in the vessel is reduced with a vacuum pull to remove the deprotecting composition without any draining step and without otherwise adversely affecting the remaining materials in the vessel or causing problems in subsequent steps in the SPPS cycle.

An improved method of deprotection in solid phase peptide synthesis is disclosed. In particular the deprotecting composition is added in high concentration and small volume to the mixture of the coupling solution, the growing peptide chain, and any excess activated acid from the preceding coupling cycle, and without any draining step between the coupling step of the previous cycle and the addition of the deprotection composition for the successive cycle. Thereafter, the ambient pressure in the vessel is reduced with a vacuum pull to remove the deprotecting composition without any draining step and without otherwise adversely affecting the remaining materials in the vessel or causing problems in subsequent steps in the SPPS cycle.

A positioning foot having a hydraulic shock absorber with a fluid-filled hollow cylinder (210), in which a piston (220) that moves axially between an advanced, spring prestressed position and a retracted position. The piston separates a front axial fluid space (214) and a rear axial fluid space (215) from one another in the hollow cylinder. Both fluid spaces are connected to one another in a fluid exchanging fashion via at least one throttle opening (223) in the piston. The piston is rigidly connected to a piston rod (221), which passes through the front fluid space and abuts a fixed stop (218) in the retracted position, in which the volume of the rear axial fluid space is minimized and the volume of the front axial fluid space is maximized. The spring prestress is dimensioned so that the weight of the device body moves the piston dampingly into the retracted position.

A positioning foot having a hydraulic shock absorber with a fluid-filled hollow cylinder (210), in which a piston (220) that moves axially between an advanced, spring prestressed position and a retracted position. The piston separates a front axial fluid space (214) and a rear axial fluid space (215) from one another in the hollow cylinder. Both fluid spaces are connected to one another in a fluid exchanging fashion via at least one throttle opening (223) in the piston. The piston is rigidly connected to a piston rod (221), which passes through the front fluid space and abuts a fixed stop (218) in the retracted position, in which the volume of the rear axial fluid space is minimized and the volume of the front axial fluid space is maximized. The spring prestress is dimensioned so that the weight of the device body moves the piston dampingly into the retracted position.

A system for weight measurement of solids in a flow stream. The system collects the solids from the flow stream in a recipient that is slidably mounted within a pressurized accumulator vessel, which is pressurized with a variable pressure due to the flow stream. A recipient stem connects the weight of the recipient to a load cell. A force on the recipient stem includes both the force of the weight of the solids and a force produced by the variable pressure acting on the cross-sectional area of the recipient stem. The variable pressure is also applied to a compensating stem to produce a compensation force that is used to cancel out the force acting on the recipient stem due to the variable pressure.

A system for weight measurement of solids in a flow stream. The system collects the solids from the flow stream in a recipient that is slidably mounted within a pressurized accumulator vessel, which is pressurized with a variable pressure due to the flow stream. A recipient stem connects the weight of the recipient to a load cell. A force on the recipient stem includes both the force of the weight of the solids and a force produced by the variable pressure acting on the cross-sectional area of the recipient stem. The variable pressure is also applied to a compensating stem to produce a compensation force that is used to cancel out the force acting on the recipient stem due to the variable pressure.

A system for weight measurement of solids in a flow stream. The system collects the solids from the flow stream in a recipient that is slidably mounted within a pressurized accumulator vessel, which is pressurized with a variable pressure due to the flow stream. A recipient stem connects the weight of the recipient to a load cell. A force on the recipient stem includes both the force of the weight of the solids and a force produced by the variable pressure acting on the cross-sectional area of the recipient stem. The variable pressure is also applied to a compensating stem to produce a compensation force that is used to cancel out the force acting on the recipient stem due to the variable pressure.

A system for weight measurement of solids in a flow stream. The system collects the solids from the flow stream in a recipient that is slidably mounted within a pressurized accumulator vessel, which is pressurized with a variable pressure due to the flow stream. A recipient stem connects the weight of the recipient to a load cell. A force on the recipient stem includes both the force of the weight of the solids and a force produced by the variable pressure acting on the cross-sectional area of the recipient stem. The variable pressure is also applied to a compensating stem to produce a compensation force that is used to cancel out the force acting on the recipient stem due to the variable pressure.