Danfoss EVT Data sheet

Data Sheet

Solenoid Valve

Type EVT

EVT high pressure range is a direct or servo operated solenoid valve specially designed to €t into CO2 transcritical refrigeration systems.

They can be applied in following applications:

• EVT 1.2 direct operated for oil return, pressure equalization/relief control, high pressure hot gas bypass/dump and hot gas defrost.

• EVT 2.0 and 3.0 servo operated for high pressure hot gas bypass/dump and hot gas defrost application.

EVT valves and coils are sold separately.

Features

• Direct and servo operated mini piston solenoid valve with compact construction

• Simple and fast mounting of Danfoss Clip-on coil

• Designed for media temperature up to 150°C

• Working pressure up to 140 bar with standard coils

• Copper solder connections for brazing

• Stainless steel connections for Swagelok €ttings

• Body material in ECO brass (lead free < 0.1%)

• Robust design ensures long lifetime

• Supplied in version normally closed (NC)

• In accordance with ◦ RoHS II

◦ REACH

◦ LVD and PED

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Solenoid Valve, Type EVT

Portfolio overview

Table 1: Portfolio overview

Features	EVT	EVT

Connection	Copper	Stainless steel

DN [mm]	1.2 – 3.0	1.2 – 3.0

Connection	ODF 3/8”	ODM 6mm

Max. working pressure [bar]	140	140

Function	NC	NC

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Solenoid Valve, Type EVT

Functions

Normally closed (NC)

Direct operated

EVT 1.2 is direct operated. This means that the valve can operate at 0bar differential pressure.

Coil voltage disconnected (closed):

When the voltage to the coil is disconnected, the armature (3) with the seat plate (6) is pressed down against the valve ori€ce by the closing spring (5) and inlet pressure. The valve will be closed for as long as the coil is disconnected.

Coil voltage connected (open):

The valve opens directly for full flow when the voltage is applied to coil, the armature (3) with seat plate is lifted clear of the valve ori€ce. The valve will be open for as long as there is voltage to the coil.

Figure 1: Direct operated

1 Valve housing

2 Cover

3 Armature assembly

4 Gasket

5 Armature spring

6 Seat plate

7 Coil O-ring

Servo operated

EVT 2.0 and 3.0 is servo operated piston solenoid valves. The servo piston principle results in a fast operating and compact valve that can open against a high differential pressure.

Coil voltage disconnected (closed):

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Solenoid Valve, Type EVT

When the coil is disconnected, the armature (3) with seat plate (6) is pressed down against the pilot ori€ce by the armature spring (8). Via the equalization ori€ce in the piston (5), the pressure above the piston rises to the same value as the inlet pressure and the piston closes the main ori€ce. The valve will be closed for as long as the coil is disconnected.

Coil voltage connected (open):

When current is applied to the coil, the armature (3) is drawn up into the magnetic €eld and opens the pilot ori€ce. This relieves the pressure above the piston (7), i.e. the space above the piston becomes connected to the outlet side of the valve. The differential pressure between inlet and outlet sides then presses the piston away from the main ori€ce and now the main ori€ce opens for full flow. Therefore, a minimum differential pressure of 2 bar is necessary to open the valve and 0.4 bar to keep it open.

Figure 2: Servo operated

1 Valve housing

2 Cover

3 Armature assembly

4 Gasket

5 Armature spring

6 Seat plate

7 Piston assembly

8 Guide pin

9 Coil O-ring

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