Spirax Sarco K Series User Manual

IM-S24-15 CH Issue 4
14
4.2 Procedure for renewing PTFE chevron gland seals
- Isolate the valve on both sides.
- Remove the actuator from the valve. Refer to the Installation and Maintenance Instructions
covering Spirax Sarco actuators.
Caution: Care should be taken in removing the bonnet since fluid under pressure may be
trapped between the isolating valves.
- Remove the lock-nut (7).
- Unscrew the bonnet nuts securing the bonnet to the body and remove the bonnet (2)
complete with the plug / stem assembly.
- Unscrew the gland nut (8), withdraw the plug / stem assembly, remove and discard the gland
seal set (10 + 11 + 15) and gland nut gasket (6).
- Examine the parts for signs of damage or deterioration and renew as necessary. Note that
score marks or scaly deposits on the valve stem (5) will lead to early failure of the seals.
- Clean the parts taking care to avoid scratching the stem or bore of the gland nut. Refit the
plug assembly into the valve body.
- Using a new bonnet gasket refit the bonnet (2) onto the valve body, leaving the stem
protruding. Replace the bonnet nuts and tighten to the recommended torque (see Table 1,
page 13), ensuring that the valve plug is centrally located in the seat whilst tightening.
- To replace the new gland seal assembly (10, 11, 15), firstly fit the gland spring (11) over
the valve stem (5). New chevron gland seals should be firmly inserted into the gland
nut (8), as shown in Figure 2. Being careful to avoid damage to the sealing edges, replace
the gland nut gasket (6). Refit the gland nut (8) over the valve stem (5), screwing down to
ensure the gasket is bedded down onto the bonnet (2).
- Ensure that the stem (5) moves freely.
- Refit the valve lock-nut (7).
- Refit the actuator, clamping nut (9) and connect the actuator to the valve stem.
- Bring the valve back into service.
- Check for any leakage at the gland.
Spring (11)
Gasket (6)
Gland nut (8)
'O' ring
Do not assemble dry as this
will damage the 'O' rings.
Upper
bearing
(10) Chevrons
(15) Lower
bearing
Seal
assembly
Fig. 2
Clamp nut (9)
Stem (5)
(2) Bonnet
(7) Lock-nut

Spirax Sarco K Series Specifications

General

Brand	Spirax Sarco
Model	K Series
Category	Control Unit
Language	English