TECHNICAL PAPER
KM 12 0621c
SQUARE FLAPS
for piping of class I
Issue: 2/01
Page: 1
Pages: 4
The square flaps (hereinafter referred to as the Flaps) are used for closing or throttling of the air
flow in piping of class I.
Operating Conditions
Transport of gaseous media with low content of abrasive dusts of max. temperature +100oC.
Maximal overpressure to 1000 Pa, maximal under-pressure to 500 Pa.
Realisation
The Flap consists from blade built into piping of class I. After assembly the Flap is
dismountable.
It is controlled by manual handle; positions of the blade adjusting are marked on the flap segment
("O" - open, "Z" - closed). The adjusted position of the blade is locked by wing nut on side of the setting
handle. The handle is parallel with the blade and indicates thus its position. All flap components are
galvanized.
Identification
The Flap of size A x B = 400 x 250 is marked as follows:
Flap 400 x 250 KM 12 0621
Note: The second size in marking (B = 250) determined the side of tube, into which the flap pins are
positioned.
Technical Data
The flap sizes (A x B) incl. all dimensions of tubes, into which the flaps are to be located and
reference weights of the Flaps are specified on fig. 1 and tab. 1.
The pressure loss factors are stated in diagram 1. The Flaps are not air-tight. The air leakage
through the blade of closed flap is stated in diagram 2.
ZVVZ a. s.
DK
Sažinova 888
399 25 MILEVSKO
Phone: 382521318
382552028
Phone/fax: 382553141
Fax: 382553185
e-mail: [email protected]
e-mail: [email protected]
A
160
180
200
225
250
280
315
B
100
125
140
160
100
125
140
160
180
100
125
140
160
180
200
100
125
140
160
180
200
225
100
125
140
160
180
200
225
250
100
125
140
160
180
200
225
250
280
100
125
140
160
180
200
225
Lmin
245
255
260
270
245
255
260
270
280
245
255
260
270
280
290
245
255
160
270
280
290
305
245
255
260
270
280
290
305
320
245
255
260
270
280
290
305
320
335
245
255
260
270
280
290
305
Tab. 1 DIMENSIONS AND
L1min Weight * )
A
65
1,28
75
1,44
80
1,52
90
1,67
355
65
1,36
75
1,52
80
1,62
90
1,78
100
1,93
65
1,45
75
1,62
80
1,72
90
1,85
100
2,04
110
2,19
400
65
1,55
75
1,72
80
1,84
90
2,00
100
2,17
110
2,34
125
2,58
65
1,66
75
1,84
80
1,95
90
2,12
100
2,30
450
110
2,47
125
2,73
140
2,96
65
1,78
75
1,98
80
2,10
90
2,27
100
2,45
110
2,64
125
2,91
140
3,18
155
3,49
500
65
1,93
75
2,14
80
2,26
90
2,45
100
2,64
110
2,84
125
3,11
WEIGHTS
B
Lmin
250 320
280 335
315 350
100 245
125 255
140 260
160 270
180 280
200 290
225 305
250 320
280 335
315 350
350 380
100 245
125 255
140 260
160 270
180 280
200 290
225 305
250 320
280 335
315 350
355 380
400 430
125 255
140 260
160 270
180 280
200 290
225 305
250 320
280 335
315 350
355 380
400 430
450 470
125 255
140 260
160 270
180 280
200 290
225 305
250 320
280 335
L1min
140
155
170
65
75
80
90
100
110
125
140
155
170
190
65
75
80
90
100
110
125
140
155
170
190
215
75
80
90
100
110
125
140
155
170
190
215
235
75
80
90
100
110
125
140
155
Weight * )
3,40
3,73
4,12
2,10
2,32
2,44
2,64
2,85
3,06
3,35
3,66
4,01
4,41
5,02
2,29
2,52
2,65
2,87
3,09
3,31
3,62
3,95
4,31
4,44
5,40
6,35
3,84
4,05
4,38
4,71
5,05
5,55
6,05
6,60
7,25
8,20
9,65
11,10
4,17
4,40
4,73
5,10
5,50
6,00
6,50
7,10
Continued
KM 12 0621c
-2-
Continuation of Tab. 1
A
500
560
B
315
355
400
450
500
140
160
180
200
225
250
280
315
355
400
450
Lmin
350
380
430
470
520
260
270
280
290
305
320
335
350
380
430
470
L1min
170
190
215
235
260
80
90
100
110
125
140
155
170
190
215
235
Weight * )
7,75
8,80
10,30
11,80
13,60
4,80
5,15
5,55
5,95
6,45
7,05
7,70
8,40
9,50
11,10
12,70
A
560
B
Lmin L1min Weight * )
500 520 260
14,60
560 580 290
17,00
630 160 270
90
5,70
180 280 100
6,10
200 290 110
6,50
225 305 125
7,10
250 320 140
7,70
280 335 155
8,35
315 350 170
9,10
355 380 190
10,30
400 430 215
12,00
450 470 235
13,70
500 520 260
15,70
560 580 290
18,20
630 650 325
21,30
* ) Flap weight (without tube)111
Fig. 1 Flap Dimensions
Diagram 1 PRESSURE LOSS FACTORS
Example:
Determination of pressure loss at ∆pz
of flap set to 600, at air speed
c = 8 m.s-1 , in nominal
flap section A x B, at air
density ρ = 1.2 kg.m-3 :
c2 . ρ
∆pz = ξ ⋅  =
2
82 . 1,2
= 2,54  =
2
= 98 ( Pa )
-3-
KM 12 0621c
Diagram 2 PENETRATION OF AIR THROUGH CLOSED FLAP
pC - difference of static pressures in front and behind the flap
QV - flap capacity (volume flow) per one meter of the flap perimeter
Example:
Determination of volume flow QV for closed flap of size 400 x 400 at static pressure difference ∆
pC = 500 Pa:
QV = QV . LO = 0,0185 .1,6 = 0,0296 m3.s-1
where LO is flap perimeter (m)
ZVVZ a. s.
DK
Sažinova 888
399 25 MILEVSKO
KM 12 0621c
Phone: 382521318
382552085
Phone/fax: 382553141
Fax: 382553185
e-mail: [email protected]
e-mail: [email protected]