Installation
TT Twin-Screw Pump -
Installation, Operation & Maintenance Manual
25
Foundation requirements
Requirements
Foundations should be of suitable mass to absorb vibration and provide a rigid support for the
unit. Use reinforcing steel as necessary. For optimal vibration performance, the foundation
should weigh between two and three times the weight of the pump.
A flat, substantial concrete foundation is necessary in order to prevent strain and distortion
when you tighten the foundation bolts. A template should be made to position and hold the
foundation bolts in place while pouring the concrete. Location and sizes of bolt holes are shown
on the certified outline drawing supplied to the purchaser. Each bolt is installed in a pipe sleeve.
The pipe sleeve allows for minor adjustments in bolt spacing after foundation is in place (Fig.
3a and 3b).
Three methods commonly used to secure and prevent bolts from turning are:
•
A washer is placed between the bolt head and pipe sleeve with a lug welded to the bolt
head (Figure 3a).
•
An opening in the foundation to allow the lower bolt head to be held with a tool (Figure 3b).
•
A bolt of rod construction with a bend
(sometimes called a “J” or “L” bolt). These are not
preferred as they tend to create localized high stresses in the concrete.
The length of the pipe sleeve (and the free length of the bolt that is not encased in concrete)
should be the greater of 12X the bolt diameter or 6” (150mm)
The inside diameter of the pipe sleeve should be two times the outside diameter of the bolt
Provision of a 3-part foundation bolt with a coupling and above foundation notch will allow
easier replacement of any foundation bolt that fails due to over tightening or other issue.
Foundation bolts must be long enough to allow for at least
1” (25mm) for grouting under the
base plate (See the figure below). When pump is level, the bolts should extend
0.25” (6mm)
through the nuts. Leave top surface of foundations rough for adherence of grout.
