Method and apparatus for measuring the pressure of a liquid
AssigneePfister GmbH
InventorHans W. Hafner
Life of this patent
Estimating the term…
Abstract
In a method and apparatus for measuring the pressure of a liquid in a closed storage tank, a measuring piston is guided in a cylinder and is acted upon on one side by a pressure dependent on the pressure to be measured, the piston being in communication with a load measuring device. In order to compensate for the pressure exerted by gas and/or vapor in the interior space of the tank, that side of the piston opposite to said one side is acted upon by this pressure. This is achieved by enclosing the cylinder and the piston in a container filled with a blocking gas, such as nitrogen. The pressure of the blocking gas in the container is controlled by a regulator operation of which is controlled by sensing means for sensing the gas and/or vapor pressure in the interior of the tank.
Claims11
A method of measuring the pressure of a liquid in a closed tank with a measuring piston which is guided in a cylinder and acted upon on one side by a pressure dependent on the pressure of said liquid and which is in communication with a load measuring device, wherein the piston is guided in the cylinder in a substantially frictionless manner by virtue of lubrication provided by a separating fluid supplied under pressure, and wherein that side of said piston remote from said one side is acted upon by a pressure corresponding to the gas and/or vapor pressure in said tank above the liquid therein.
An apparatus for measuring the pressure of a liquid in a closed tank comprising in combination:
- a measuring piston guided in a cylinder and having one surface acted upon by pressure dependent on the pressure to be measured;
- a load measuring device connected to the piston;
- means providing lubrication by a separating fluid under pressure to said piston whereby the piston is guided in the cylinder in a substantially frictionless manner;
- a pressure-tight container enclosing the piston and cylinder with an opposed surface of the piston exposed to the pressure in the container;
- and a pressure transmitting means for transmitting to the interior of said container a pressure dependent on the gas and/or vapor pressure in a tank above liquid in said tank.
An apparatus for measuring the pressure of a liquid in a closed tank comprising in combination:
- a measuring piston guided in a cylinder;
- means communicating with one end of the cylinder to deliver a pressure commensurate with the pressure of the liquid in the tank to one end of the piston;
- a load measuring device connected to the piston;
- a pressure-tight container housing said piston and cylinder with the opposite end of the piston exposed to the pressure in said container;
- and a pressure transmitting means for transmitting to the interior of said container a pressure which is a function of the pressure in said tank above the liquid therein.
Dependencies are inferred from the claim text.