Danfoss Types ICS3-65,ICS3-100 and ICS3-150 Pilot-operated servo valve Design

ICS valves are designed as pilot operated valves requiring minimal pressure differential to open.If the pressure difference is 0 bar/0 psi, the ICS valve will be closed. If the pressure difference is 0.2 bar/3 psi or more, the ICS valve will be fully open. At pressure differences between 0.07 bar/1psi and 0.2 bar /3 psi, the opening degree will be correspondingly proportional.

The ICS is available for use with either one or three pilot valves. Two of the three pilot pressure connections (S1 and S2) are connected in series whilst the third (P) is connected in parallel to S1 and S2. This allows different combinations of pilot valves to be used, thus providing numerous variations in control functions.

Connections

There is a very wide range of connection types available with ICS valves:

• D: Butt weld, DIN (2448)

• A: Butt weld, ANSI (B 36.10)

• J: Butt weld, JIS (B S 602)

• SOC: Socket weld, ANSI (B 16.11)

• SD: Solder connection, DIN (2856)

• SA: Solder connection, ANSI (B 16.22)

• FPT: Female pipe thread (ANSI/ASME B 1.20.1)

Approvals

The ICV valve concept is designed to fulfill global refrigeration requirements.For specific approval information, please contact Danfoss.

The ICS valves are approved in accordance with the European standard specified in the Pressure Equipment Directive and are CE marked. For further details / restrictions - see Installation

Instruction

Valve body and top cover material Low temperature steel

Danfoss Types ICS3-65,ICS3-100 and ICS3-150 Pilot-operated servo valve Function

The ICS main valve is a pilot operated valve. The types of pilot valves used determine the function.The ICS main valve with pilot valve(s) controls refrigerant flow by modulation or on/off in accordance with the pilot valve and main valve status. The manual spindle can be used to open

the valve plate. The opening degree of the main valve is determined by the pressure difference (differential pressure) between pressure p 2 , which

acts on top of the servo piston (3b), and pressure p 3 , which acts on the underside of the servo piston.If this pressure difference is 0, the main valve will be fully closed.If the pressure difference is 0.2 bar (3 psi) or greater, the main valve will be fully open.At pressure differences (p 2 - p 3 ) between 0.07 bar(1 psi) and 0.2 bar (3 psi), the degree of opening

will be correspondingly proportional.

The port of the throttle cone (3e) is V-shaped,which provide good regulation characteristic to pilot operated main valves even at low loads.

P 3 pressure is equal to the valve outlet pressure (P 4 ), due to a clearance between the piston rod (3g) and the function module. The opening

degree of the ICS valve is therefore controlled by the application of P 2 pressure acting on top of the servo piston, which is equal to or greater than valve outlet pressure (P 4 ).

p 2 = p 4 ~ closed

p 2 = p 4 + 0.2 bar (3 psi)~ fully open

p 4 ≤ p 2 ≤ p 4 + 0.2 bar (3 psi) ~ proportional degree of opening.

The maximum pressure (p 2 ) can act on the top of the servo piston (3b). p 2 normally corresponds to the pressure, p 1 - ICS main valve inlet pressure. Inlet pressure p 1 is led, via the drilled channels (1a, 1b, 2f, 2b (pilot), 2a, 2d) in the valve body (1) and cover (2) through the individual pilot valves and onto the top of the servo piston (3b).The degree of opening of the individual pilot valves determines the magnitude of pressure p 2 and thus the degree of opening of the main valve. The equalisation hole (3f) in the servo piston (3b) ensures that pressure p 2 is balanced in accordance with the degree of opening of the pilot valve.

Note:

When ICS valves with 3 pilot ports are used with external pressure connector (fig. 2, pos. 61), the valve port inlet pressure will be isolated. The ICS can be fitted with just a single screwed- in pilot valve or external pilot connection. The degree of opening of the main valve will be in accordance with the control status of the pilot valve or external pilot flow control.

Danfoss Types ICS3-65,ICS3-100 and ICS3-150 Pilot-operated servo valve Function

ICS main valve with one pilot connection is fully closed when the pilot valve is fully closed and fully open when the pilot valve is fully open. Otherwise the degree of opening of the main valve is proportional to the degree of opening of the pilot valve. The ICS 3 pilot version can be fitted with one, two, or three pilot valves so that up to three regulating functions are possible. If the external pilot connection is used, more functions can be added. In the ICS three pilot version, the pilot ports are related as follows:

• The pilot valves fitted in ports SI and SII are connected in series.The ICS 3 pilot operated main valve will be fully closed if just one of the series-connected pilot valves is closed. The main valve can only open if both pilot valves are open at the same time.

• The pilot valve fitted in port P is connected in parallel to the pilot valves in ports SI and SII.The ICS valve will be fully open if the pilot valve in P is fully open, irrespective of the degree of opening of pilot valves SI and SII. The ICS valve will be fully closed if the pilot valve

in P is fully closed and at least one of the valves in SI or SII is fully closed at the same time. The relation between the pilot valves in ports SI, SII and P is shown in the table on the next page. If the ICS is not fitted with three pilot valves, the unused port(s) must be sealed with a

blanking plug. If the blanking plug is fitted as an assembled unit, A + B, the channels from the specific port will be closed. (See illustration

below) If only the top part, A, of the plug is fitted, the channels from the ports in question will be open. If the degree of opening of the ICS main valve is not to be a function of the main valve inlet pressure, or if more than three regulating functions are required, ports SI, SII or P can be fitted with a nipple for the connection of external pilot pressure. This applies to all ICS versions. The pressure to which the external pilot line is connected will then determine pressure p 2 on top of the servo piston. The pilot valves fitted in that external pilot line will determine the main valve function. Pilot valves installed in external lines must be mounted in a type CVH housing. Depending on the function of the pilot valves, the ICS regulating characteristic becomes:

• on/off

• proportional

• integral or

• cascade.

ICS main valves are therefore especially suitable for all forms of temperature and pressure regulating systems.An overview of the types of pilot valves available can be found in the literature “Pilot valves for

operated main valves” (DKRCI.PD.HN0).On the following pages, a number of

configuration examples can be found. These are only for explanatory purpose. However, by using the literature regarding pilot valves these examples are easier to comprehend.