Danfoss SV 1, SV 3 Data sheet

Data Sheet
Float valve Type SV 1 and SV 3
For industrial refrigeration liquid level regulation
Several oat valves are available for Industrial refrigeration liquid level control in the product group “Liquid level regulating valves”, such as HFI and SV series. The SV series contains the following types: SV 1, SV 3, SV 4, SV 5 and SV 6, some of which can be delivered as dedicated “E” versions for hydrocarbon application.
The SV 1 and SV 3 can be used separately as a modulating liquid level regulator in refrigerating, freezing and air conditioning systems for ammonia or uorinated refrigerants.However, in most cases, the SV is used as a oat pilot valve for the main expansion valve type PMFH.
The SV 1 and SV 3 are used as liquid level regulators in either low pressure applications or in high pressure applications. Adaptation to the specic application is done by the orientation of the valve and thereby the oat functions
AI221686430747en-001001
Description
Values
Refrigerants
R134a, R22, R401A, R402A, R404A, R407A, R407B, R407C, R407F, R409A, R410A, R421A, R502, R507, R717
Application
High Pressure Liquid Level Control System (HP LLRS) Low Pressure Liquid Level Control System (LP LLRS)
Design versions
Media temperature range
-50 °C – 65 °C
P-band [mm]
35 mm
MWP [bar]
28 bar
K
v
value [m3/h]
0.06 for SV 1
0.14 for SV 3
Rated capacity (kW)
SV1: 25 SV3: 64 (R717 +5/32 °C, Tl = 28 °C)
Float valve, Type SV 1 and SV 3
Portfolio overview
The SV 1 and SV 3 can be used separately as a modulating liquid level regulator in refrigerating, freezing and air conditioning systems for ammonia or uorinated refrigerants.
However, in most cases, the SV is used as a oat pilot valve for the main expansion valve type PMFH.
Several oat valves are available for Industrial refrigeration liquid level control in the product group “Liquid level regulating valves”, such as HFI and SV series. The SV series contains the following types: SV 1, SV 3, SV 4, SV 5 and SV 6, some of which can be delivered as dedicated “E” versions for hydrocarbon application.
Figure 1: Float valve SV 1 and SV 3
Table 1: Portfolio overview
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Float valve, Type SV 1 and SV 3
Applications
SV (L), low-pressure function
SV (L), low-pressure function
SV (L) is used for small, ooded evaporators, where only slight variations in the liquid level can be accepted.
When the liquid level falls, the oat pos. (2) moves downwards. This draws the needle pos. (15) away from the orice and the amount of liquid injected is increased.
The liquid inlet line, which is mounted on the nipple pos. (C), should be dimensioned in such a way that acceptable
liquid velocities and pressure drops are obtained.
This is particularly important when the liquid is only slightly subcooled, since valve capacity is reduced considerably if ashgas occurs in the liquid ahead of the orice and wear is strongly increased.
See the suggested dimensions for the liquid line in "Pipe dimensions". Refer section Dimensions and weights
The ashgas quantity which occurs on expansion is removed through the balance pipe from pos. (D). On refrigeration plant using uorinated refrigerants, slight subcooling and a large pressure drop can give a ashgas quantity of approx. 50% of the injected liquid quantity. Therefore the pressure drop in this balance pipe must be kept at a minimum, since there will otherwise be a risk that the liquid level in the evaporator will vary to an unacceptable degree as a function of evaporator load the absolute dierence between the liquid level of the evaporator and the SV valve will be too large.
See the suggested dimensions for the balance pipe in "Pipe dimensions". Refer section Dimensions and weights
Figure 2: SV (L), low-pressure function
SV (H), high-pressure function
SV (H), high-pressure function
When the liquid level rises, the oat pos. (2) moves upwards. This draws the needle pos. (15) away from the orice and the excess liquid is drawn away.
On refrigeration plant using uorinated refrigerants slight subcooling and a large pressure drop can, as already mentioned, cause the formation of a large amount of ashgas.
This mixture of liquid and vapour has to pass through the nipple pos. (C) and out into the liquidline.
If the dimensions of the line are too small, a pressure drop will occur which can reduce the capacity of the SV (H) valve considerably. This will mean a risk of inadvertent liquid accumulation in the condenser or receiver.
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SV(L)
10 32 22
P-connection
SV(L)
10 32 22
S-connection
Float valve, Type SV 1 and SV 3
See the suggested dimensions for the liquid line in "Pipe dimensions". Refer section Dimensions and weights
Figure 3: SV (H), high-pressure function
The connection nipple (C) can be mounted either in P or in S
Figure 4: P-connection (= parallel)
NOTE:
With P-connection an SV with closed oat orice will have a capacity which corresponds to the degree of opening of the adjustable throttle valve 10.
Figure 5: S-connection (= series)
NOTE:
With S-connection the throttle valve 10 will function as a pre-orice on SV (L) and as a post orice on SV (H)
SV 1 - 3 used as a high pressure defrost drain oat valve
SV 1 - SV 3 can be used as a defrost drain oat valve, when one balance pipe is sealed o and the liquid level regulator is mounted with a special kit (code no. 027B2054) consisting of:
• Special orice and orice needle with a larger kv-value of 0.28 m3/h.
• Gas drain pipe
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Liquid out to wet suction
Condensed liquid in from evaporator
Wet suction line
Liquid line
PMLX
SVI-3
EVRAT
EVRAT
REG
NRVA
Hotgas line
EVRAT
FA
FA
Float valve, Type SV 1 and SV 3
Figure 6: SV 1 - 3 tted with the special kit (code no. 027B2054)
Figure 7: Application example
NOTE:
SV 1 - 3 with special kit mounted as defrost drain foat valve on a fooded evaporator with hotgas defrost.
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