Specifications

Chapter 14: Appendices
Appendix 11: Engineering Specifications
(12/99) 14-35
Flexmount HD Weigh
Modules
The portions of this specification that have been left blank ( __________ ) should be
filled with information about the specific application. Information for the blanks in
Section 1.1 can be found in Table 14-25. Information for the blanks in Sections 4.2.1 to
4.2.9 can be found in Table 14-26.
1 General Provisions
1.1 Provide a complete system consisting of ______ (qty) ______ lb
carbon steel weigh modules to convert a freestanding structure into a
scale.
1.2 Each module shall include load cell, top and bottom mounting plates,
self-aligning suspension, and anti-lift restraints.
1.3 The system shall include a stainless steel NEMA 4X/IP65 summing
junction box.
1.4 Each weigh module shall be completely factory assembled.
2 Mechanical Specifications
2.1 The system shall be completely self-checking. No additional check
rods, links, or stays are required.
2.2 One module of the system shall be of a fixed-pin design so that all
vessel movements, including those caused by thermal expansion and
contraction, will be relative to that point. The influence of any
plumbing (inlet/outlet pipes, etc.) attached to the vessel at the fixed-
pin location shall have a minimal influence on weigh vessel
accuracy.
2.3 One module of the system shall be of a semi-floating design to allow
for movement of the vessel due to thermal expansion toward and
away from the fixed-pin module. This module shall also provide anti-
rotational vessel checking in a horizontal plane.
2.4 All remaining modules shall be of a full-floating design, allowing the
top mounting plates to move laterally in all directions without
imposing a side force on the cells, which would produce weighing
errors.
2.5 The load point on each load cell shall remain stationary. Modules
shall be designed to allow movement of the module top mounting
plate without changing the load point on the load cell, or allowing the
load introduction mechanism between the top plate and the load cell
to be out of a vertical position. Load cells which allow movement of
the load point on the load cell are not acceptable.
2.6 The load introduction mechanism between the top plate and the load
cell shall be a pin design constructed of hardened 17-4ph stainless
steel. The load pin shall have an O-ring seal at one end to prevent dirt
and other foreign material from entering the load cell bearing surface.
Direct bolt connections between the top mounting plate and the load
cell are not acceptable.
2.7 Each module shall be equipped with two integral hold-down bolts
designed to prevent the vessel from being uplifted off the weigh
module.
2.8 The hold-down bolts shall serve as alignment tools to correctly
position the top mounting plate over the load cell during installation.
2.9 The hold-down bolts shall secure the top plate during shipping and
installation. They shall be capable of taking the load off the load cell
to protect the load cell from possible shock during shipping and
installation. In addition, the hold-down bolts shall facilitate load cell
replacement by serving as a jacking device for the empty vessel.