| 摘要 |
The invention relates to a back-pressure control valve with a housing which has at least one inlet opening which is connected to a source of fluid, and furthermore has at least one outlet opening, via which a first fluid supplied by the source of fluid is mixed with a second fluid, the pressure of which is present at the outlet opening, the inlet and outlet opening being connected via a valve controllable as a function of pressure, the valve-closing member of which is guided displaceably in a hole formed in the housing and is preloaded in the closing direction against the pressure of the first fluid by a spring. In pumps of various designs, a reduction in the delivery rate occurs with increasing output pressure. In order to avoid this disadvantage, the back-pressure control valve is designed in such a way that the spring is supported against a piston arranged displaceably in a chamber which is formed in the housing and is divided by the piston into a pressure chamber and a spring chamber in which is arranged a pre-loading spring supported against the piston and assisting the pre-loading force of the spring, and the pressure chamber is supplied with the pressure of the second fluid, as a result of which the total pre-loading force acting on the valve-closing member in the closing direction is altered by the pressure of the second fluid in such a way that a constant back-pressure is established for the source of fluid. <IMAGE>
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