Flowserve Valtek FlowTop V750 User Instructions page 6

Valtek FlowTop
The successful sizing and selection of control valves depends on the knowledge of the actual process condi-
NOTICE
tions in the system in which the valve will be installed. This clear information about the operating conditions
is not always available. However, the more assumptions made about the flow conditions, the less accurate the sizing of the
control valve. Basically, control valves are designed according to the operating data specified by the customer. The following
standards can be used to calculate control valves: Kv value calculation - EN 60543-2-1, ANSI / ISA 75.01.01 and noise calcula-
tion - EN 60534-8-3, EN 60534-8-4, VDMA 24 422/1979/1989 (withdrawn). If these calculations attest a critical valve operating
condition, the selection of suitable trims divides these into several uncritical throttle points. Since all these calculations con-
sider only the punctual installation location of the valve, these are only valid under the condition of an "undisturbed pipe flow
profile". This pipe flow can only be achieved by professional piping - according to the recognized rules of technology - with
sufficient distance to sources of interference such as pumps, bends, T-pieces, pipe extensions, pipe reducers or other valves.
Yes, even improperly executed welds near the control valve can affect design accuracy and adversely affect the predicted valve
behavior. The minimum SPR (straight piping run) should be 0.5 meters or 6 x DN upstream and downstream of the valve.
In case of problematic operating conditions (cavitation, evaporation, two-phase flow, noise, excessive medium speeds, etc.)
double the downstream section. As a preventive measure, vibration situations and pressure pulsations in the pipeline can be
identified by pulsation studies (VDI 3842) by the plant planner or operator and avoided by suitable planning measures. Experi-
ence has shown that control valves are operated continuously with a workload of 10 - 90%. In particular, continuous operation
< 10 % can damage the control valve. Subsequent changes using a modified interior trim are only possible to a limited extent
and do not always lead to success. In the worst case, such a problem can be resolved only by a subsequent expensive pipe
change. Flowserve Control Valves GmbH is a manufacturer of valves, not a piping contractor. Our expertise is in the design and
manufacture of control valves. This does not include piping design and layouts. It is in the responsibility of the plant planner /
operator to install the valve to good piping practices. We kindly provide this information based on our wealth of experience and
expressly emphasize that we cannot in any way accept responsibility for the actual performance of a pipeline installation result-
ing from the recommendations given here.
As a rule, it should be assumed that the shorter the straight pipe run before a valve, the higher the probability of turbulent flow
into the valve.
Prior to installation of the valve, we require, that you check the following conditions to reduce the risk of malfunction and
safety related incidents.
No.
1 Confirm that the nominal / operational data on the
serial plate matches the operational data of the
facility.
2 Confirm that the line is clear of dirt, welding slag,
chips, scale or other foreign material.
3 Confirm the piping flanges are coaxial, parallel, and
correspond with the face-to-face dimension of the
valve.
4 Confirm the piping is routed correctly and the valve is
free of additional piping forces.
5 Confirm that the control valve can be installed in an
upright position whenever possible.
6
FCD VLEEIM1485-04 (EN/A4) November 2022
Check Possible malfunction or safety related incident
An operational mismatch can cause considerable damage to
the valve or may lead to a failure at the facility.
The risk of control valve damage due to foreign particles will be
reduced if a suitable strainer is installed upstream of the valve.
(Suggested mesh size of 0.004 inch (0,1 mm)
Incompatible sizing may result in excessive tension, valve
malfunction or flange connection leakage.
Incorrect routing may result in leakage and / or potential valve
failure.
Non-upright positioning may increase wear in the packing,
resulting in leakage and premature wear.