Dwyer DA-7035N - Manual

Installation Instructions (Preliminary)
Series D-7000-(N) Remote Bulb Temperature Controls
Bulletin IN-526-N
MERCOID DIVISION
Phone: 219/879-8000 www.dwyer-inst.com
DWYER INSTRUMENTS, INC. Fax: 219/872-9057 e-mail: [email protected]
P.O. BOX 258 • MICHIGAN CITY, INDIANA 46361, U.S.A.
CONTROL NUMBERS
Part of the control number following Type No. Prefix identifies the style of the
control case.
The digit 5 of 7035 denotes a plain case with bottom connection.
The digit 8 of 7038 denotes a flanged case with bottom connection.
The digit 9 of 7039 denotes a flanged case with back connection.
CIRCUITS (SWITCH OPERATION)
Suffix number after control number denotes number of circuits and circuit
operation.
Suffix -153 designates SPDT - one circuit closes as other circuit opens.
Suffix - 804 designates 2 ea. SPDT switches - two circuits close as two cir-
cuits open.
LOCATION AND MOUNTING OF CONTROL CASE
Follow equipment manufacturer’s instructions or proceed as follows:
Vibration causes erratic operation of any instrument and shortens its life. It is
important to select a location that is reasonably free of vibration. All controls
must be mounted vertical and level. Delrin bushed movements prolong con-
trol life by alleviating excessive wear of metal surfaces due to vibration and/or
pulsation. It is identified by the letter “B” after the suffix number. Example: -
2B, -3B, -804B, etc.
General Purpose Types - DA, DS, DL, DR - These controls without a
flange plate are mounted by means of a bracket supplied with the control. For
panel mounted use the holes provided on the flanged case. See drawing
1000F on page 4.
Weather Resistant Types - DAW, DSW, DRW, DLW - For surface mount-
ing only. Has flanged case with bottom connection. See drawing 1062 on
page 4.
Explosion-Proof Types - DAE, DSE, DLE, DRE, DLH, DAH, DSH, DRH -
Secure with the mounting lugs provided on the housing. See drawings 98D
and 1350 on page 4.
LOCATION OF REMOTE BULB
To Insure Proper Control Operation:
1. The temperature bulb should be completely immersed in the medium being
controlled.
2. BULB MUST BE CORRECTLY LOCATED AND PROPERLY INSTALLED so
that the temperature changes at the bulb reflect actual temperature changes
of the medium being controlled.
3. Be sure the bulb will not be affected by external temperatures.
4. Bulb may be installed vertically or horizontally. The following precautions
should be taken:
(a) Do not install bulb in dead end of pipe, tank, etc., where it would not be
subject to free circulation of the medium being controlled. See illustration No.
5.
(b) If bulb No. 2 is located in a pipe or duct with diameter larger than the bulb
length, the bulb can be installed perpendicular to the pipe if protected from
possible damage due to flow velocity.
(c) If bulb No. 2 is to be inserted into a pipe with a diameter smaller than the
bulb length (ex. a 2-7/8˝ long bulb in a 1˝ pipe) the bulb should be located lon-
gitudinaly in the pipe so that the entire length is exposed to the flowing medi-
um (ex. replace an elbow in the pipe with a tee and install bulb as shown in
illustration No. 6 and 7. If pipe is 1˝ diameter or less, provide an enlarged sec-
tion around the bulb so that it does not restrict flow.
(d) When bulb No. 2 is to be inserted in a rapidly flowing stream of fluid in a
pipe or duct, make sure that it is mechanicaly protected against the velocity
in order to prevent the bulb from breaking off at the capillary.
5. Gas activated bulbs, unlike vapor pressure bulbs, do not have any eleva-
tion effects. Therefore, no compensation is required.
BULB PROTECTION
There are three ways to protect bulb No. 2:
1. Before tightening packing gland, pull bulb back into union as far as possi-
ble (standard No. 2 bulb with 3/4˝ union only). The union is recessed to pro-
vide some support.
2. Where insertion depth is greater than bulb length, use extension sleeve “B”.
See illustration Nos. 8, 9, and 10.
3. Separable Wells (see drawing No. 10): wells slow down heat transfer of
temperature changes to the bulb and consequently increase response time
of control the union will slide back on capillary allowing complete immersion
of bulb in any depth of well.
FOR DIMENSIONS OF BULBS, SEE CHART - PAGE 3
Caution: When installing bulbs with union connections, be careful not to twist
the flexible tubing. Loosen packing nut or union so that the union can turn
freely around tubing. After union is firmly secured to the pipe or tank, position
bulb by sliding tubing through union and then tighten the packing gland nut.
CROSS AMBIENT TEMPERATURE EFFECTS
There are no cross ambient effects associated with these gas actuated units
which are designed with a range number ending with “n”, i.e. -5N.
WHERE TURBULENT OR FAST
FLOWING LIQUIDS PREVAIL
Bulb supports for bulb No. 2 are used where the bulb is mounted in turbulent
or fast flowing liquids or where it is desired to insert the remote bulb at some
distance within a vessel, pipe, or tank. See “B” in illustration Nos. 8, 9 and 10.
The remote bulb should be positioned so that at least one inch of the bulb is
within the extension sleeve “B” (dimension “B”) in order to insure firm support.
No. 2 bulb union is threaded to receive extension sleeve “B”. Extension addi-
tion “A” permits extending the mounting through insulation.
INCORRECT
INSTALLATION
Note that a very small
portion of the bulb is
exposed to the direct
path of medium being
controlled. section
containing bulb has
no flow so its temper-
ature is affected by
radiation to or from
the surrounding air.
RECOMMENDED
INSTALLATION
These two illustrations indicate the bulb is completely
exposed (in direct path) of medium being controlled.
ILLUSTRATION NO. 5
ILLUSTRATION
NO. 6
ILLUSTRATION
NO. 7
ILLUSTRATION
NO. 8
ILLUSTRATION
NO. 9
GENERAL PURPOSE
Prefixed by
DA, DL, DR, DS
WEATHER-RESISTANT
Prefixed by
DAW, DLW, DRW, DSW
EXPLOSION PROOF
Prefixed by
DAH, DLH, DRH, DSH
EXPLOSION PROOF
Prefixed by
DAE, DLE, DRE, DSE
ENCLOSURES – TYPE NO. PREFIX
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