Manual through-conduit construction
This page covers a 304 stainless steel manual geared through-conduit knife gate valve. The handwheel and mechanical transmission move the gate linearly for an accepted isolation duty. Confirm the gate opening, seats, packing and full travel on the supplied sectional and dimensional drawings.
Bevel and worm gearing are not interchangeable descriptions
The manual gearbox is selected for the required operating force and installation conditions. Provide the fluid, temperature, pressure, closing differential, size and operating frequency. The selected gearbox documents identify its mechanism, stages, ratio, input torque, output thrust and any holding function.
Materials and supply limits
The 304 designation is not an ASTM casting specification and does not identify every component or establish resistance to all acids and alkalis or hygienic/GMP compliance. Confirm body, gate, seat, packing and their material standards separately. Complete-valve temperature and pressure limits, seating, elastomers and leakage acceptance depend on the supplied configuration. PN and Class are not directly interchangeable working pressures.
Media, throttling and maintenance
A through-conduit passage does not mean no blockage, no pressure loss or an ability to cut every solid. State slurry concentration, particle size, fibres, deposits, crystallisation and abrasion. Intermediate positioning does not establish continuous throttling suitability: assess the gate, seats, differential, erosion and vibration. Provide full travel, guards, handwheel and maintenance space. Isolate and depressurise before service; in-line replacement under pressure is not promised.
Procurement checks
Provide temperature, pressure, shutoff differential, connection dimensions, cycle frequency and installation layout. Request the matching gearbox data, materials list, dimensional and sectional drawings, and test requirements. For motorisation, also specify interface, thrust/torque, travel and limit controls.
Frequently asked questions
Are bevel and worm gears always fitted together?
No. They are different mechanisms; the actual arrangement requires a gearbox nameplate or assembly drawing.
Does 304 mean every part is the same cast steel?
No. Confirm each component grade, product form and specification. A 304 label is not a casting certificate.
Can it throttle continuously at partial opening?
Only after checking the specific design, differential, erosion and vibration. Manual positioning is not proof of control-valve performance.
