Rovalve S20
Installation and Maintenance Instructions
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page 8
8. Converting MH to BG valves
Bevel gear conversion for the Rovalve S20 is very simple. It is not necessary to remove the 4-Post
yoke assembly. Conversion kits include bevel gear operator with integral thrust style stem nut,
conversion mounting plate, appropriate bolts, and handwheel or drive nut as required. Existing
stem and yoke posts will be reused. If stem or yoke posts require replacement, contact the
factory.
CAUTION
Follow required safety procedure and policies. Assure line is not pressurized or gate has been
secured to prevent unwanted movement before disassembly. Use proper lifting and support
techniques when moving valve and or valve subassemblies.
Tools required:
1. Pipe wrench or large crescent wrench
2. Appropriate size open end wrenches or sockets
Prepare the valve:
1. Line should be depressurized or gate secured prior to disassembly. If valve is equipped with
pin-style lockouts (see figure 12) gate can be locked in the open or closed position using the
lock pin. If pin-style lockouts are not present, the gate must be held in place to prevent
unwanted movement. These precautions are necessary to keep the gate from moving.
Disassembly:
1. Using pipe wrench or crescent wrench, remove handwheel retaining nut from stem nut.
2. Remove handwheel.
3. Remove (2) or (4) retainer bolts.
4. Pull retainer off
5. Rotate old stem nut until free from stem.
6. Remove nuts from the 4-post yoke legs.
7. Pull existing top plate up and away from valve.
Reassembly:
1. The conversion kit will be shipped with the thrust stem nut installed within the bevel gear.
2. Place the adapter plate over the 4-Post yoke legs aligning the holes.
3. Attach nuts onto 4-post yoke legs securing the top plate into position.
4. Slip the bevel gear over the stem nut, engaging the threads. Rotate the handwheel which will in
turn rotate the thrust stem nut down the stem, bringing the bevel gear into proper position,
aligning the bolt holes.
5. Bolt the bevel gear to the adapter plate. Do not overstress bolting.
6. Stroke the valve from full open to full closed making sure all parts are aligned and working
properly. Check bolts for tightness, the gate and operator assembly should stay snug with the
valve body.
7. If binding or off-center movement of gate is evident, loosen yoke bolts, stroke gate up and
down a few times, retighten yoke bolts.
Figure 12
Figure 13
L1: Pin style, both open and closed
lockpositions
L2: Pin style, open position only
L3: Pin style, closed position only.
L6: Case hardened pin for use on L1,
L2 or L3
BG bevel gear
actuator
open
closed
closed
open
pin
Thrust-style stemnut
included in BG
BG mount plate
BG mount bolts
4-Post yoke leg
Stem
