Honeywell C7015A Manual Do Utilizador

INSTALLATION

is available to facilitate flame sighting after the 

 is pipe diameter is reduced, the effect is the same as adding an

mounted. orifice plate to the pipe as discussed below.

FIELD OF VIEW

A lead sulfide photocell, like other photocells, views an

area rather than a point. It is unable to pinpoint pilot flame

 

 

 it must view only a part of   

 viewing area must not be so large

that a weak and wavering pilot flame could energize the

photocell and cause the flame relay to pull in.

The area viewed by the photocell depends on:

1. Diameter of 

 opening in front of the cell.

2. Distance from the cell to the opening.

3. Distance from the opening to the area to be viewed.

Fig. 2 shows three ways of reducing the field of view,

assuming that the distance from the viewing opening to the

flame or refractory cannot be changed. These are (1) length-

ening the sight pipe, (2) reducing the diameter of the sight

pipe, and (3) installing an orifice plate in front of the photo-

cell. Combinations of these methods can   used.

AREA 

0

 UNRESTRICTED VIEW

BY LENGTHENING

THE SIGHT PIPE

CHANGING PIPE LENGTH OR SIZE (DIAMETER)

Theeffectorchangingthelengthofthesightpipeisshown

in Tables 2 and 3.

Changing the diameter of the sight pipe is not as simple as

changing the 

 the 

 mount and mount-

ing accessories are all sized for 

 in. pipe. When the sight

TABLE 2-DIAMETER OF AREA SIGHTED THROUGH VARIOUS LENGTHS OF 

 -IN. PIPE

WITHOUT ORIFICE, IN IN.

7 1.5 2.3 3.1 3.9 4.7 5.5 6.3 7.1   8.0 8.7 9.6 10.4

8 1.4 2.1 2.8 3.5 4.2 4.9 5.6 6.3   7.1 7.7 8.5 

TABLE 3-DIAMETER OF AREA SIGHTED THROUGH VARIOUS LENGTHS OF 

 IN. PIPE

WITHOUT ORIFICE. IN MM

Over 1016.0