The direction arrow identifies the intended relationship between the flow and the internal trim. For a unidirectional V-port configuration, reversing the valve can change seating behavior, torque and control performance.
Pressure direction is part of the design
Differential pressure can load the seat and rotating element in different ways. Some configurations are designed to use pressure to assist seating in a particular direction. Others have separately qualified reverse-pressure performance. Do not infer bidirectional shut-off merely because liquid can physically pass through the body both ways.
Read the selected drawing
Use the approved datasheet, body marking and installation drawing for the exact series. If those documents disagree, stop and resolve the discrepancy before pressurizing. A drawing for a different seat arrangement is not sufficient evidence. The supplied VQ47 and VQ77 flyer identifies unidirectional flow for those catalogue platforms.
Replacement and commissioning checks
Photograph the old installation and record normal and possible reverse pressures before removal. Confirm the new body arrow relative to plant flow, then verify shaft rotation and the actuator’s indication. Stroke and indication checks must be performed with the process safely isolated and according to the operating procedure.
Practical checklist
- Normal flow and reverse-pressure cases are documented.
- Body arrow agrees with the approved drawing.
- Actuator indication matches actual segment position.
- Any reverse-pressure requirement is accepted in writing.
Discuss your application
Send the process conditions and required valve function for a configuration review. Request a technical quotation ↗