KOBOLD PPS FLOW SWITCH
User Instructions
USA
1801 Parkway View Drive
Pittsburgh, PA 15205
412-788-2830
Fax: 412-788-4890
www.koboldusa.com
Canada
9A Aviation
Point Claire, QC H9R 4Z2
514-428-8090
Fax: 514-428-8899
PPS_manual_0314
Table Of Contents
KOBOLD PPS FLOW SWITCH
1.0 General . . . . . . . . .. . . . . . . . . . . . . . . . . 1
2.0 Specifications. . . . . .. . . . . . . . . . . . . . . . . 2
3.0 Installation . . . . . . .. . . . . . . . . . . . . . . . . 4
4.0 Operation . . . . . . . .. . . . . . . . . . . . . . . . . 5
4.1 Adjustment of the Setpoint. . . . . . . . . . . . 5
5.0 Maintenance . . . . . .. . . . . . . . . . . . . . . . . 5
6.0 Damaged Equipment. . . . . . . . . . . . . . . . 5
7.0 Need Help with your PPS. . . . . . . . . . . . . 5
LIST of DIAGRAMS
PPS
Diagram 1.1 PPS Operating Principle . . . . . . . . . . . . . 1
Diagram 2.2 PPS Construction & Dimensions . . . . . . . 3
LIST of TABLES
Table 2.1 Reed Switch Electrical Data. . . . . . . . . . . 2
Table 2.3 Construction . . . . . .. . . . . . . . . . . . . . . . . 3
Table 2.4 Switching Point vs. Pipe Diameter. . . . . . 4
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KOBOLD PPS FLOW SWITCH
User Instructions
CAUTION: For safety reasons, please read the cautionary information located at
the end of the manual, before attempting installation.
1.0 General
The KOBOLD PPS flow switch is intended for applications in which an electrical
switching function is required once a specific flow rate is achieved.
The PPS is delivered with
changeover (SPDT) switching function, depending upon ordering code. Switching is
achieved through a magnetically-coupled reed switch which is hermetically isolated
from the medium. The device operates through use of a paddle which is pivoted out of
the fluid system by flow pressure. A cam attached to the top of the paddle then lifts
internal magnets into a region near the reed switch. The magnetic field of the magnets
then activates the reed contacts. A spring acts against the force of the paddle to force
magnets out of reed switch proximity if flow volume decreases beyond a specific value
(determined by pipe diameter & paddle length). (See Diagram 1.1)
Once the PPS has switched, the paddle is almost totally removed from the flow path.
This guarantees a minimal pressure loss across the instrument of ~1.45 PSI max.
either a normally-open (N/O), normally-closed (N/C) or
Diagram 1.1: PPS Operating Principle
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2.0 Specifications
Operating Principle:
Dimensions:
Switching Points:
Maximum Pressure:
Maximum Media Temperature:
Maximum Induced Pressure Loss:
Switching Repeatability:
Fitting:
Electrical Connection:
Spring resisted paddle, cam assisted
See Diagram 2.2
See Table 2.4
145 PSIG
225° F
1.45 PSI
± 3%
1” MNPT or G1 (1” BSP) male
DIN 43 650 Plug/Socket
Table 2.1: Reed Switch Electrical Data
Maximum Voltage:
Maximum Current:
Maximum Load:
E
nvironmental Protection:
250 VA
100 VDC (SPDT)
2.0 A (N/O, N/C)
0.5 A (SPDT)
40 W/40 VA (N/O, N/C)
5 W (SPDT)
NEMA 4 / IP 65
C/VDC (N/O, N/C)
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Diagram 2.2: PPS Construction & Dimensions
Table 2.3: Construction
Wetted Materials
Body: Polysulfone
Spring: Stainless Steel
Magnet: Ceramic
Pivot Pin: Stainless Steel
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Table 2.4: Switching Point vs. Pipe Diameter
Pipe Cut-off Switching point GPM Water
bore mark "L"
inches appr. Turn-on Turn-off
10.9"9.5 5.0
1 1/4 1.1" 9.5 5.0
1 1/2 1.4" 14.5 9.5
2 2.0" 19.0 9.5
2 1/2 2.4" 24.0 14.5
3 2.9" 28.5 19.0
3.0 - Installation
CAUTION: For safety reasons, please read the cautionary information
located at the end of the manual, before attempting installation.
Electrical Connection:
The PPS is designed to be directly mounted into the top of pipes through the use of a
1” NPT fitting. Use PTFE sealing tape for proper sealing and ease of installation.
When installing, it is important to note the following:
1. The flat of the paddle faces into the fluid stream.
2. The paddle is trimmed to the appropriate length of the diameter of the pipe
into which it is installed to achieve the design switchpoint (Table 2.4).
3. The PPS is not so deeply inserted into the pipe so that the paddle touches the
bottom of the pipe.
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4.0 Operation
The PPS comes with either an N/O, N/C (at no flow) or SPDT switch as specified by the
order code. The switching function is factory set and is not adjustable. The reed switch
of the PPS may be used to switch loads directly as long as switch limits are not
exceeded (see Table 2.1). For DC circuits, we strongly suggest the use of a 1A,
1N4000 series diode wired in parallel with the load (e.g. band or cathode toward
positive). For AC loads, use an RC circuit or MOV (metal oxide varistor) wired in
parallel with the switch.
It is important to realize that large capacitive or inductive loads (such as relay coils, light
bulbs, etc.) typically have momentary voltage/current requirements far exceeding any of
the rated operating values of the reed switch. If in doubt, we suggest the use of a higher
capacity isolation relay (such as the Kobold MSR or RL series) to protect your model
PPS flow switch.
4.1 Adjustment of the Setpoint
The switch setpoint is adjustable only via the paddle length. If a higher switchpoint is
desired, paddle length may be changed by additional trimming of the paddle. There is no
specified procedure for this, but in general, for a given pipe diameter:
1. Longer Paddle: Lower switch point
2. Shorter Paddle: Higher switch point
5.0 Maintenance
The simplicity of the device ensures that it is nearly maintenance free. If the media is
dirty, it is possible that the dirt will deposit in the switch body and impede the motion of
the ceramic magnet. In this case, remove the device and clean as appropriate. Do not
use sharp objects to scrape away dirt as this may damage the PPS. After cleaning,
reinstall as per the installation instructions.
6.0 Arrival of Damaged Equipment
Your instrument was inspected prior to shipment and found to be defect-free. If damage
is visible on the unit, we advise that you carefully inspect the packing in which it was
delivered. If damage is visible, notify your local carrier at once, since the carrier is liable
for a replacement under these circumstances. If your claim is refused, please contact
KOBOLD Instruments for further advisement.
7.0 Need help with your PPS
Call one of our friendly engineers at 412-788-2830.
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CAUTION!
PLEASE READ THE FOLLOWING GENERAL FLOW METER /
MONITOR WARNINGS BEFORE ATTEMPTING INSTALLATION OF
YOUR NEW DEVICE. FAILURE TO HEED THE INFORMATION HEREIN
MAY RESULT IN EQUIPMENT FAILURE AND POSSIBLE
SUBSEQUENT PERSONAL INJURY.
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• KOBOLD manufactures a wide range of process sensors and
technologies. While each of these technologies are designed to operate in
a wide variety of applications, it is the user’s responsibility to select a
technology that is appropriate for the application, to install it properly, to
perform tests of the installed system, and to maintain all components. The
failure to do so could result in property damage or serious injury.
• Inspect instrument for damage upon arrival. Cracked, fractured, bent, or
otherwise damaged instruments must not be put into use, since the device
is weakened to an unknown extent. (The operations and installation guide
will explain how to make a claim on damaged instruments.)
• Make sure that the model which you have selected is chemically
compatible with the application liquids. While the meter is liquid and spray
resistant when installed properly, it is not to be submerged in liquids.
• Under NO circumstances must the maximum tolerances (temperature and
pressure) be exceeded.
• The maximum tolerances of the device have been determined using water,
air and/or oil. If using other media, especially corrosive ones, it is critically
important that the user determine chemical compatibility with our
instruments. A list, detailing material composition of our instruments, is
available from KOBOLD Instruments Inc. upon request. KOBOLD
Instruments Inc. cannot accept responsibility for failure and consequences
resulting from use of media other than water, mineral oil, air, and nitrogen.
• Install the devices in a fully supported position within your flow system. This
avoids excessive stresses which may damage the instrument. In particular:
a. Ensure that the plumbing leading to and from the instrument is fully
supported and that the instrument does not perform the physical function
of a joint.
b. When calculating stress on the device caused by plumbing, the weight of
the medium in the pipes must be considered as well.
c. Misaligned runs of rigid piping can cause large stresses when connected
to the instrument. Do not connect in such a fashion.
• During installation, avoid stresses on the instrument by following guidelines
given below:
a. When connecting fittings, hold the instrument fittings rigid with a
correctly sized wrench. Do not install by twisting the instrument into the
pipe fittings.
b. Do NOT install holding the device housing to provide counter-torque to
the pipe fitting.
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c. Use an appropriate amount of PTFE tape on male threads of fitting. This
reduces the twisting stresses produced by tightening the fittings into
each other.
d. Do not use pliers or wrenches on the housing, as this may damage it.
e. Do not overtighten, as this may fracture the fittings.
• During operation, there are a number of situations to avoid:
a. The sudden cessation of fluid flow causes what is typically referred to as
“water hammer”. Most people are familiar with this phenomenon from
their home experience - it is the cause behind the loud clank of water
pipes which occurs when faucets are turned off too suddenly. The cause
behind this “water hammer” is quite easy to visualize. Water is fairly
massive. The amount of water in long runs of pipe is quite substantial.
When the faucets are turned off suddenly, especially from a full on
condition, the water has considerable momentum and does not want to
stop flowing. The situation is similar to stopping a car by running into a
wall, rather than by applying brakes. Both are sudden rather than
gradual. The damage to the wall can be substantial (not to mention the
car).
The “water hammer” causes surges in fluid pressure which could cause
the measurement instrument’s pressure limit to be exceeded, resulting
in failure and possible personal injury.
b. Fluid surges, as well as the water hammer, can be particularly damaging
to empty flow meters since there is no back pressure in the device. The
damage is caused, once again, by momentary excess pressure. To
avoid these surges, fluid lines should remain full (if possible) and water
flow should be introduced to the device slowly.
c. If the instrument is isolated with inlet and outlet valves, the flow meter
must be completely drained when said valves are both closed. Failure to
do so could result in damage to the device caused by thermal expansion
of fluid.
d. Freezing of water in the instrument must be avoided since the resultant
expansion will damage the flow meter and make it unsafe for use.
• Design a fail-safe system
a. Design a fail-safe system that accommodates the possibility of switch or
power failure. In critical applications, KOBOLD recommends the use of
redundant backup systems and alarms in addition to the primary
system.
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