Danfoss SCA-X, CHV-X Data sheet
Data sheet
Check & stop valve, SCA-X
Check valve, CHV-X
SCA-X are check valves with a built-in shut-off valve
function. SCA-X valves are avilable in angleway
versions.
CHV-X are check valves only. CHV-X are available in
both angleway and straightway versions.
The valves are designed to open at very low
differential pressures, allow favourable flow
conditions and are easy to disassemble for
inspection and service.
The SCA-X is equipped with vented cap and has
internal backseating enabling the spindle seal to be
replaced whilst the valve still under pressure.
Laser cut V-ports provide excellent opening
characteristics (SCA-X/CHV-X 50-125).
The valve cone has a built-in flexibility to ensure a
precise and tight closing towards the valve seat.
Features • Applicable to HCFC, HFC, R717 (Ammonia), R744
(CO2), Propane, Butane, Iso-Butane and Ethane.
R717 Heat Pump and Propylene applications with
replaced O-ring.
• Modular Concept:
– Each valve housing is available with several
different connection types and sizes.
– Possible to convert SCA-X or CHV-X to any
other product in the FlexlineTM SVL family
(Hand operated regulating valve, shut-off
valve or strainer) just by replacing the
complete top part.
• Fast and easy valve overhaul service. It is easy to
replace the top part and no welding is needed.
• Designed to open at a very low differential pressure of 0.04 bar /0.58 psig.
• Designed with a built-in damping chamber preventing valve flutter in case of low
refrigerant velocity and/or low density.
• Each valve is clearly marked with type, size and
performance range.
Additional ID ring to be installed when preparing
for Ammonia Heat Pump or Propylene
application.
A well balanced dampening effect between the
piston and the cylinder gives an optimal protection
during low loads and against pulsations.
• Easy to disassemble for inspection and service.
• Internal backseating enables replacement of the
spindle seal whilst the valve is active, i.e. under
pressure.
• Optimal flow characteristics ensuring quick opening to the fully open position.
• Protection against pulsation by built-in
damping facility.
• Housing and bonnet material is low
temperature steel according to requirements of
the Pressure Equipment Directive and other international classification authorities.
• Equipped with Stainless steel bolts.
• Max. working pressure:
52 bar g / 754 psi g
• Temperature range:
-60 – 150 °C / -76 – 302 °F
• Classification: DNV, CRN, BV, EAC etc.
To get an updated list of certification on the
products please contact your local Danfoss Sales
Company.
© Danfoss | DCS (MWA) | 2018.11
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SCA-X
Danfoss
M148G0005_1
Data sheet | Check & stop valve, type SCA-X - Check valve, type CHV-X
Design
Connections
Available with the following connections:
• Butt-weld DIN (EN 10220)
DN 15 - 125 (½ - 5 in.)
• Butt-weld ANSI (B 36.10 Schedule 80),
DN 15 - 40 (½ - 1½ in.)
• Butt-weld ANSI (B 36.10 Schedule 40),
DN 50 - 125 (2 - 5 in.)
• Butt-weld GOST, (8734-75 and 8732-78)
DN 15 - 125 (½ - 5 in.)
• Socket-weld ANSI (B 16.11),
DN 50 (2 in.)
Housing
The housing is made from special, cold resistant steel.
Valve cone
Valve cone with built in metallic stop - prevents
damage to teflon ring in case of overtightening.
Damping chamber
The chamber is filled with refrigerants (gas or liquid),
which provides a damping effect when the valve
opens and closes.
Spindle (SCA-X)
Made of polished stainless steel, which is ideal for
O-ring sealing.
Packing Gland (SCA-X)
The “full temperature range” packing gland is the
standard for the entire SVL platform.
This ensures perfect tightness throughout the whole
temperature range:
-60 – 150 °C / -76 – 302 °F.
Pressure Equipment Directive (PED)
The SCA-X/CHV-X valves are approved according
to the European standard specified in the Pressure
Equipment Directive and are CE marked.
For further details / restrictions - see the product
instruction.
Installation
The valve must be mounted vertically with the cone
downwards.
The valve is designed to resist very high internal
pressure. However, the piping system in general should
be designed to avoid liquid traps and reduce the risk of
hydraulic pressure caused by thermal expansion.
For further information refer to installation instructions
for SCA-X/CHV-X.
If cold refrigeration oil having low viscosity enters
and settles in the damping chamber, problems with
the check valve may arise. Consequently, it may be
necessary to modify the valve for more viscous liquids
by enlarging the hole to the damping chamber.
Example of marking ring, CHV-X
Nominal bore DN = < 25 mm (1 in.) DN32-80 mm (1¼ - 3 in.) DN100 - 125 mm (4 - 5 in.)
Classified for Fluid group I
Category Article 3, paragraph 3 II III
Application Figure 3 shows the check & stop valve SCA-X in
the discharge line of a screw compressor unit.
The SCA-X valve in the discharge line prevents
“back condensation” in the oil separator as well as
pressure equalising through the compressor.
Compared to an ordinary shut-off and check
valve arrangement the combined check & stop
valve solution, as shown, is easier to install and
has lower flow resistance.
Installation of the SCA-X/CHV-X in the
economizer line is not recommended.
For horizontal installation of the function module;
please contact Danfoss.
SCA-X/CHV-X valves
Compressor
Oil cooler
Oil separator
Fig. 3
© Danfoss | DCS (MWA) | 2018.11
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Data sheet | Check & stop valve, type SCA-X - Check valve, type CHV-X
Technical data
• Refrigerants
Applicable to HCFC, HFC, R717 (Ammonia), R744
(CO2), Propane, Butane, Iso-Butane and Ethane.
R717 Heat Pump and Propylene applications with
replaced O-ring.
Computation and selection Introduction
When dimensioning SCA-X/CHV-X, it is important
to select a valve that is best suited to all operating
conditions. Therefore, it is necessary to consider
both the nominal and part load working conditions.
Example
SI-Units
Assumed working conditions:
Maximum flow = 1000 m3/h
Density ρ = 3.0 kg/m
Minimum part load = 33%
Used expressions:
Recommended velocity - C
Minimum recommended velocity - C
Maximum velocity - C
Part load velocity - C
We know the density ρ ≈ 3.0 kg/m3, consequently
C
as well as C
rec
below (standard valve).
3
[m/s]
rec
[m/s]
max
[m/s]
part
can be found in the figure
min, rec
min, rec
[m/s]
• Temperature range
-60 – 150 °C / -76 – 302 °F.
• Max. working pressure
52 bar g / 754 psig.
The SCA-X/CHV-X valve can be calculated in two
ways:
– Using the tables below.
– Using Coolselector®2
US-Units
Assumed working conditions:
Maximum flow = 1160 gpm
Density ρ = 0.187 lb/feet
3
Minimum part load = 33%
Used expressions:
Recommended velocity - C
Minimum recommended velocity - C
Maximum velocity - C
Part load velocity - C
part
[ft/min]
max
[ft/min]
[ft/min]
rec
min, rec
[ft/min]
We know the density ρ ≈ 0.187 lb/feet3,
consequently C
as well as C
rec
can be found in
min, rec
the figure (standard valve).
C
≈14 m/s
rec
C
min, rec
Fig. 1
≈ 3 m/s
C
= 14 m/s
rec
C
= 2756 ft/min
rec
C
= 3 m/s
min, rec
C
= 591 ft/min
min, rec
Velocity
m/s
[ft/min]
Not
recommended
C
≈ 2756 ft/min
rec
C
≈ 591 ft/min
min, rec
Recommended
velocity
ρ = 3.0 kg/m
ρ = 0.187 lb/feet
3
3
Density
kg/m
3
[lb/feet3]
© Danfoss | DCS (MWA) | 2018.11
Selection example continued on following page.
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Data sheet | Check & stop valve, type SCA-X - Check valve, type CHV-X
Computation and selection
(continued)
Knowing that = 1000 m3/h (1160 gpm) fig. 2 gives the following choices:
For SCA-X/CHV-X in size DN 100 the maximum velocity C
For SCA-X/CHV-X in size DN 125 the maximum velocity C
In conclusion SCA-X in size DN 125 is selected
because C
to the recommended velocity C
≈ 20 m/s (3900 ft/min) comes nearest
max
≈ 14 m/s (2756 ft/
rec
min) and at the same time part load conditions fulfil
the requirements, as described:
≈ 31 m/s (6100 ft/min)
max
≈ 20 m/s (3900 ft/min)
max
(3.0 m/s)
and the sele cted SCA-X model DN125 is
the perfect choice.
lf the valve in question (for instance under part load
conditions) provides a velocity less than
C
the valve might start hammering and
min, rec
become noisy. As a result the valve may wear
We know that C
minimum part load is 33%. lt fol lows that
m/s (1290 ft/min). Thus, C
DN 15 - 40
m/s
[ft/min]
≈ 20 m/s (3900 ft/min) and that
max
SCA
(6.5 m/s) > C
part
15
20
V-X
/CHV-X
X
-
-X/CH
CA
S
SC
X/CHV-X
-
A
2
5
C
part
min, rec
SCA-X/CHV-X 32
≈ 6.5
prematurely.
CA-X/CHV-X 40
S
Danfoss
M148G0003_1
© Danfoss | DCS (MWA) | 2018.11
SCA-X/CHV-X 100
SCA-X/CHV-X 125
Fig. 2
DN 50 - 125
m/s
[ft/min]
[m/s]
m3/h
[gpm]
Danfoss
M148G0004_1
0
5
-X
V
H
X/CHV-X 65
-
-X/C
A
CA
C
SCA-X/CHV-X 80
S
S
SCA-X/CHV-X 100
SCA-X
125
/CHV-X
m3/h
= 1000 m3/h
[gpm]
= 1160 gpm
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Danfoss
M148G0009_1
1
2
3
5
14
13
12
6
15
17
8
9
4
3
12
13
7
14
5
1
16
15
2
6
11
10
Danfoss
M148G0008_1
Danfoss
148G237_02-2017
Data sheet | Check & stop valve, type SCA-X - Check valve, type CHV-X
Material specification
12
2
3
13
14
5
6
1
SCA-X 15 - 40
No. Part Material DIN/EN ISO ASTM
1 Housing Steel P285QH
2 Bonnet, Flange Steel P275NL1
3 Bonnet, Insert Steel
4 Spindle Stainless steel X 10CrNiS18-9 Type 17, 17440 AISI 303, 683/13
5 Cone Steel
6
7 Spindle extension Steel
8 Packing gland
9 Packing washer Aluminium
10 Spring loaded seal Teflon (PTFE)
11 O-ring Cloroprene (Neoprene)
12 Bolts Stainless steel A2-70 A2-70 Type 308
13 Gasket Fiber, non-asbestos
14 Spring Steel
15 Identification ring Stainless steel
16 Seal cap gasket Nylon
17 Spindle seal cap Aluminium
O-ring Cloroprene (Neoprene)
Teflon (PTFE)
O-rings
Steel
Cloroprene (Neoprene)
CHV-X 15 - 40
EN10222-4
EN10028-3
CHV-X 15 - 40
LF2A350
15
© Danfoss | DCS (MWA) | 2018.11
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