Load-holding valve
In accordance with ISO 1219-1 load-holding valves are classed in the group of pressure control valves. They prevent double-acting consumers (such as hydraulic cylinders and hydraulic motors) that have
Roof-shaped seal
which several, often with different materials, are assembled to form roof-shaped seal sets (Figure D 1) . In principle a differentiation is made between two forms: In form (a) the limbs are in contact with
Flow coefficient Kv (Kv value) of a valve
quantity of water in m3 (L) that flows through a valve in one hour (minute) with a pressure drop of 1 bar (VDI 2173). The Kv value is therefore a parameter for the selection of valve sizes. It can be converted
Pressure gauge
is made between tube-type, diaphragm, bourdon tube and corrugated tube pressure gauges ( Figure M 1 a and b ).
Following control valve
change with respect to each other until the difference to the actual value is zero again ( Figure N 1 ).
Kv value (of valves)
water at +5 to +30°C passing through a device (valve) in a given direction based on a pressure drop of 1 bar and an upstream pressure of 6 bar. The practical benefits of the Kv value (of valves) are disputed
Servo valve
into a path, which is taken over by the hydraulic control unit. A distinction is made between 1-stage and 2-stage or 3-stage servo valves. In one-stage servo valves, the electrical input stage (torque motor [...] from the valve to the consumer if approximately 1/3 of the available system pressure p max reaches the pressure difference on the valve and approximately 2/3 is available as load pressure on the consumer
Pressure loss through a fitting
number Re . Samples for the back pressure coefficient ξ: enum-title straight fitting: 0.5 ankle fitting: 1 90° elbow (r/d=3): 0.2 45° elbow (r/d=3): 0.13 Calculate the pressure loss through a fitting directly
Transfer element
system with input variables u 1 (t ) ... u p (t ) and output variables v 1 (t ) ... v q (t ), which has a certain transfer function , is called a transfer element (EDIN 19 226 Part 2) ( Figure U 8 ). A transfer
Rotary flow divider
the subflows can also be different in terms of amounts and can result in improved accuracy (approx. 1-1.5% leakage losses). Toothed wheel flow dividers are made for up to six subflows. Alternative: Flow