Burkert Type 3285 (SKU 20038308) is a direct-acting electromotive 2-way disc proportional valve suitable for dosing liquids and gases in closed or open control loops. The valve is driven by a stepper motor with an integrated electronics assembly that simplifies process integration, eliminating the need for additional actuation modules. The motor does not require energy to maintain a specific valve opening, which dramatically reduces the energy consumption of a plant and increases efficiency. This specific model features a G 1/2" internal thread connection, an 8 mm seat diameter, and operates within a 0 to 6 bar pressure range with a Kv value of 1.8 m³/h.

The Type 3285 disc valve consists of a stepper motor with a gearbox that transfers rotational torque to the actuator shaft via a coupling. The actuator shaft has a control/shut-off disc attached to it. A fixed disk with a mouth attached to the body is used as a valve seat. The control/shut-off disc is pressed onto the fixed disk by a supporting spring. The actuator turns the control/shut-off disc about 180° above the fixed disc to open or close the valve seat.

Key Features

• Actuator isolated from the flow path
• Excellent range and fast response times
• Low power consumption (<1 W in holding position)
• Flow direction above seat
• Available variants: standard (on/off, control), positioner, process controller

General Technical Data

Property	Specification
Seal Material	EPDM for liquids and special gases; FKM for neutral gases
Seat Sealing	Technical ceramics (Oxide ceramics)
Valve Body	Brass, stainless steel
Flow Direction	Above seat
Design	Disc on/off valve / Disc control valve
Operating Pressure	0...6 bar(g)
Duty Cycle	Up to 100% (depending on medium and ambient temperature)
Operating Voltage	24 V DC ± 10% (max. residual ripple 10%)
Power Consumption	<1 W in holding position; Max. 12 W (depending on motor control)
Medium Temperature	EPDM: -30 °C...+70 °C; FKM, NBR: 0 °C...+70 °C
Ambient Temperature	-10 °C...+60 °C (Observe derating curve)
Viscosity	Max. 80 mm²/s (cSt)
Degree of Protection	IP50

Materials

Actuator

No.	Element	Material
1	Housing cover	PC (Polycarbonate)
2	Housing base	PPS (Polyphenylenesulfide)

Valve Body

No.	Element	Material
3	Spindle	Stainless steel 1.4404/1.4401
4	Spindle seal	FKM/EPDM/NBR
5	Disc	Technical ceramics
6	Valve seat	Technical ceramics
7	Valve body	Brass or stainless steel 1.4408
8	O-ring	FKM/EPDM/NBR
9	O-ring	FKM/EPDM/NBR
10	Parallel pin	Stainless steel 1.4401
11	Spring	Spring steel/stainless steel

Dimensions

INFO

Dimensions in mm. The globe control valve Type 3285 is supplied with various port connections. These connections correspond to the material of the valve housing.

A	B	C	D	E	F	G	H
-	-	14	G 1/2	97	138	31	58
-	-	16	G 3/4	103.5	147	43	80
-	-	18	G 1	108.5	156.5	49	95

Electrical Connections

Pin Assignment Analogue

Pin	Configuration
1	24 V DC
2	Power supply GND
3	Internal use
4	Internal use
5	Internal use
6	Signal input +
7	Signal output
8	Signal GND

Pin Assignment Digital (Fieldbus)

Pin	Configuration
1	Shield
2	24 V DC
3	GND
4	CAN_H
5	CAN_L

Performance Specifications

Duty Cycle Derating

WARNING

The duty cycle is an important factor for motor valves. The self-heating of the engine limits the maximum duty cycle. High ambient temperatures additionally increase the risk of damage due to overheating. Operating the valve outside the recommended duty cycle limits will result in a significantly reduced service life.

Derating curve for standard version

Derating curve for positioner and process controller

Pressure Range

Valve function	Seat size	Port connection	Kvs-value water [m³/h]	Pressure range [bar(g)]
Control valve, without safety position in case of power failure	8	G 1/2	1.8	6
	10	G 1/2	2.5	6
	12	G 3/4	3.9	6
	15	G 3/4	5.4	6
	20	G 1	8.1	6
	25	G 1	9.6	6

Product Operation

Standard on/off valve In the on/off variant, an external voltage signal is digitized and the valve is closed or opened. The status of the two end positions of the valve are indicated on the LED. In addition, the valve position "closed" is reached via the digital output.

Standard control valve The standard proportional valve converts an external standard signal (position set-point value) into a valve position. Both valve end positions are indicated by the LED status.

Process diagram

Positioner variant The proportional valve in the position control variant converts an external standard signal, the position set-point value, into a valve position. The position of the actuator is controlled according to the set-point position. The position sensor records the current position (POS) of the electromotive valve.

Process controller variant The additionally implemented PID controller can perform not only the actual position control but also a process control in the sense of a cascade control. The position setpoint of the valve is calculated from the process setpoint and the actual process value via the control parameters (PID controller).