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en:rueckstromsperren:zylindrisches_und_konisches_rsp-element [2024/10/28 20:26] – neelesten:rueckstromsperren:zylindrisches_und_konisches_rsp-element [2025/05/06 15:29] (aktuell) – cschall
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-======Cylindrical and conical RSP element ======+======NRV - Cylindrical and conical NRV element ====== 
 + 
 +The cylindrical and conical NRV element, the ring and the pipe segment are auxiliary geometries in order to be able to map the pressure loss of a non-return valve with the simplest possible input parameters.
  
 ===== Cylindrical and conical RSP element ===== ===== Cylindrical and conical RSP element =====
  
-The ring non-return valve (RSP) is a screw component that is only available in PSI. In injection moulding screws, it prevents the molten material from flowing back into the screw during the injection process. The RSP has a three-part design. It consists of the pressure ring, the locking tip and the locking ring. +These two parts correspond to the respective shearing elements; the input is analogue. 
- +
-**Function** +
- +
-The function of the RSP is basically as follows: During dosing, the material in the screw is conveyed forwards by the hopper and melted in the process. The material flowing forwards presses the laterally movable locking ring against the locking tip. The material flows between the wings of the barrier tip into the screw vestibule. After dosing, the material is pressed down. No further material is conveyed through the screw. The material flows back into the screw due to the pressure gradient. The locking ring is pushed back and hits the cone of the pressure ring. As this is not permeable, unlike the tip of the vane, the locking ring and pressure ring close the screw and prevent any further backflow.  +
- +
-When dosing starts again, the material conveyed forwards by the screw pushes the locking ring forwards again so that the screw chamber can be filled. +
- +
-**Structure** +
- +
-As mentioned above, the ring non-return valve is basically made up of three parts. In addition to the main components pressure ring, locking ring and locking tip, the centre piece between the pressure ring and locking tip must also be defined in PSI. +
- +
-{{ :rueckstromsperren:abb_ringrueckstromsperre_en.png?nolink |}} +
- +
-The RSP begins with the design of the pressure ring. Its task is to seal the screw against backflowing material when it is pressed down in combination with the locking ring. For this purpose, it has a conical contact surface against which the locking ring presses. +
- +
-{{ :rueckstromsperren:rex171_rsp_en_005.png?nolink |}} +
- +
-The design of this cone is of decisive importance for the functionality of the lock, as it forms the sealing surface for the locking ring. It is therefore possible to design it in detail in REX.  +
- +
-The centre pieces follow the pressure ring. Depending on the original geometry used, it is possible to assemble the centre piece from different individual geometries. +
- +
-{{ :rueckstromsperren:rex171_rsp_en_006.png?nolink |}} +
- +
-The centre piece forms the connection between the pressure ring and the barrier tip. Together with the locking ring, the centre piece forms the flow channel for the melt and thus creates a decisive flow cross-section. If it is too large, the pressure on the locking ring is reduced so that it does not slide quickly enough into the locking position. If the flow cross-section is too small, the melt is severely impeded from flowing into the screw vestibule.  +
- +
-The centre section is then followed by the barrier tip. It is designed as a wing tip. This allows the melt to flow through the tip during dosing when the locking ring is in the front position and into the screw vestibule. It should be designed to allow the melt to flow as freely as possible into the screw vestibule, avoiding dead zones. The rear side of the blades serves as a contact surface for the locking ring during dosing. They must be designed accordingly as a contact surface. This applies in particular to the blade angle $β_{Fl}$. This must correspond to the angle of the corresponding contact surface of the locking ring.  +
- +
-The number of vanes is freely selectable. It should be selected in combination with the vane geometry so that the resulting flow cross-section is sufficient for the required amount of melt. As can be seen in the schematic diagram, the geometry is differentiated according to whether a $R_{Flg}$ is specified or not. +
- +
-{{ :rueckstromsperren:rex171_rsp_en_007.png?nolink |}} +
- +
-The last component is the locking ring. It is movably mounted to open the screw during dosing and to close the screw against backflowing material during injection. +
- +
-{{ :rueckstromsperren:rex171_rsp_en_008.png?nolink |}} +
- +
-Dabei liegt er zunächst an der Sperrenspitze bzw. beim Schließen am Druckring an. Die Anlageflächen des Sperrringes sind also von entscheidender Bedeutung für die Funktion der RSP. Es ist darauf zu achten, dass die Winkel der Anlageflächen auf beiden Seiten so gewählt werden, dass die Flächen plan aufeinander liegen. Der Außendurchmesser ist etwas kleiner als der Zylinderinnendurchmesser zu wählen: Zum einen muss die laterale Beweglichkeit des Ringes gewährleistet sein. Zum anderen führt der Ring auch eine Rotationsbewegung durch: Wird er während des Dosiervorganges gegen die rotierende Sperrenspitze gedrückt, nimmt diese den Ring mit und zwingt ihn in eine rotierende Bewegung.+
  
-{{ :rueckstromsperren:rex171_rsp_en_009.png?nolink |}}+{{ :rueckstromsperren:rex171_rsp_en_001.png?nolink |}} 
 +{{ :rueckstromsperren:rex171_rsp_en_002.png?nolink |}}
  
 ===Further topics=== ===Further topics===