DAYLIFF DS, Инструкция по установке и эксплуатации, Страница: 5 / 16

Fig. 2 Wellhead layout
Sleeve for
airline
Regulator Valve
Test Tee
Junction Box
Cover Plate
Drop Pipe
3
iii) Wellhead
A robust sealed wellhead plate should
be fitted on the borehole top to prevent
borehole contamination, a DAYLIFF
w e l l h e a d a s s e m b l y b e i n g
recommended. The assembly includes
a delivery outlet with isolating valve and
test tee as well as drop cable entry and
optional provision for low-level
electrode cables and an airline to
measure borehole water depth.
Ÿ
For single phase pumps 3-core cable is suitable. For three phase pumps 3-core
can be used with steel pipes installation using the drop pipe for earthing. 4-core
must be used for plastic pipe installations.
Ÿ
It is important that the correct cable size is selected which is related to motor size
and total length. Voltage drop should not exceed 5% from the supply point. The
pump supplier should be consulted for the correct cable size.
Ÿ
The drop cable must be attached to the pump tail cable using a certified cable
joint. Leakage at this joint will cause motor failure.
Ÿ
Care must be taken when fitting the motor tail cable to the motor. The connection
between the tail cable and the motor should be lubricated with a non-conducting
petroleum jelly and a secure fit made with the securing screws fully tightened.
i) Riser Pipe
Suitable selection and installation of the riser pipe is essential to avoid the risk of pipe
fracture and pump dislodging. This will then require expensive pump removal or
possibly borehole loss. The following should be noted:-
Ÿ
Either MS galvanised steel pipe in 6m or 3m sections or DAYLIFF PVC borehole
piping in 3m section should be used for all installations below 50m. For shallow
well installations up to 50m single length Polypipe can be used.
Ÿ
For MS steel pipe ensure that all threads are properly cut and that the connecting
sockets are fully threaded. For deep boreholes (deeper than 100m) high tensile
'Crane' type sockets are recommended. Steel pipes are recommended for all 6''
pump installations.
Ÿ
For reasons of reduced friction, ease of installation and economy ‘DAYLIFF' PVC
borehole pipe are recommended for all 3”and 4'' pump installations up to 200m
depth. Standard PVC piping must never be used.