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Sentry_Cooler_SD1741_iom_D100
Sentry Sample Coolers
Standard Installation & Operating Instructions
SD 1741
Rev. 14
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CAUTION: Vibration is the typical cause of Sample Cooler failure. Vibration is caused by two (2) conditions:
1. Cavitation results whenever localized boiling occurs on the outside surface of the hot heat transfer coil. Steam
bubbles form on the shell side of the hot coil surface and are swept into the main stream of the cooling water where
they immediately condense and collapse. The collapsing bubbles generate severe shock waves (i.e. vibrations)
which can fatigue and ultimately fracture the heat transfer coil.
Cavitation is caused by: (a) the cooling water flow rate is too low, such that the water is overheated to its boiling
point, and/or (b) the cooling water operating pressure it too low, such that the cooling water can boil at a low
temperature.
Cavitation can be prevented if: (a) the cooling water and sample flows are kept within the design conditions
specified in Sentry literature, and (b) the cooling water pressure is kept as high as possible - 50 psig (3 barg)
minimum recommended. To avoid reducing the cooling water pressure in the shellside, throttle only at the cooling
water outlet - never at the inlet. The cooling water outlet temperature should not be allowed to exceed 140°F
(60°C).
2. Excessive cooling water flow can cause vibration of the heat transfer coil due to the effect of vortex shedding.
This can lead to coil failure and can be prevented by throttling the cooling water flow to design conditions.
If you hear vibration or rattling noises from the cooler, take corrective action immediately to:
*
Eliminate vibration from cavitation by adjusting cooler so that:
a) Cooling water inlet valve is fully open.
b) Cooling water flow is per design condition.
c) Cooling water shellside pressure is as high as possible.
d) Sample flow is reduced if necessary.
*
Eliminate vibration from excessive velocity by throttling cooling water flow. Always throttle at
the cooling water outlet.
Installation
1. Support the cooler by its bracket(s) or by water lines only. All coolers have brackets except type TW.
2. The cooling water should be softened and free of chlorides. Any hardness in the cooling water will result in scale
build up on the coil and a loss of heat transfer capacity. Chlorides can cause pitting or stress corrosion in stainless
steel. If no source of acceptable cooling water is available, consult Sentry for a recommendation.
3. Provide a globe (not gate) valve in the cooling water outlet line for throttling purposes. Valve size must be same
as cooling water outlet connection.
4. If isolation of the cooler is desired, provide a gate or ball valve (not globe) in the cooling water inlet line. Valve
size must be same as cooling water inlet connection. If a cooling water inlet valve is installed, a relief valve or 3way valve must be provided per paragraph 7 below.
5. Mount the cooler either vertically or horizontally (preferably vertical on high temperature lines).
6. Installer shall connect to the cooling water connections and sample fluid tube stubs by means of fittings or
welding, as appropriate. A 90° bend or expansion loop must be provided in the hot sample line to the cooler. This
allows the tubing to expand or contract with temperature changes without inducing stress at the point where the tube
is welded to the cooler head.
Sentry Equipment Corp • PO Box 127 • Oconomowoc, WI 53066
Phone: 262-567-7256 • Fax: 262-567-4523 • E-mail: [email protected]
Web Site: http://www.sentry-equip.com
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Sentry Sample Coolers
Standard Installation & Operating Instructions
SD1741
Rev. 14
7. A relief valve should be installed in the cooling water line between the cooler and the outlet or the inlet valve.
This protects against excessive shell side pressure in the event of (a) a leak in the high pressure tubing, or (b) an
operator turning on the hot sample flow with both cooling water isolation valves closed, thus boiling the coolant and
pressurizing the shell. As an option, a 3-way valve can be used on the inlet. It should be oriented so that the shell is
open to drain when the cooling water is shut off.
Start-Up & Operation
1. Fully open all cooling water valves. Verify that minimum required cooling water flow is occurring. If cooling
water is untreated, its temperature rise should not exceed 30°F (17°C) so as to minimize scaling. Be sure that the
outlet temperature does not exceed 140°F (60°C).
2. When necessary, throttle cooling water flow by partially closing the globe valve on the cooling water outlet line.
Any valve on the cooling water inlet line must always be fully open.
Disassembly & Reassembly
1. For heavily scaled coolers, disassembly is made easier by first dissolving the scale. Remove scale by circulating
an inhibited sulfamic acid cleaning solution through the cooling water side.
2. Replace used gaskets with new ones. After reassembly, pressurize shell and visually inspect for water leaks.
Replace gaskets which show visible leaks. Keep spare shell gaskets on hand for this need.
3. During reassembly tighten the bolts only enough so that shell side leaking does not occur. Over tightening may
cause gasket failure.
Sentry Equipment Corp • PO Box 127 • Oconomowoc, WI 53066Phone: 262-567-7256 • Fax: 262-567-4523
E-mail: [email protected] • Web Site: http://www.sentry-equip.com