• Low Pressure Proportional Regulator(0-8bar)
Low Pressure Proportional Regulator(0-8bar)
Product Serial: QKL-B1T/QKL-B3-1/QKL-B3-1A

Low Pressure Proportional Regulator(0-8bar)
There are 3 different series of 0-8 bar proportional pressure regulator- low flow < 20L/min, high flow >500 L/min, and economic type high flow. The low flow version consists of two solenoid valves, one high-processing speed digital electronic board, and one pressure transducer. The high flow version’s construct is similar, but adding a volume booster. The economic type of proportional pressure regulator is the one where we offer a reasonable accuracy 0.5%, high speed, and economics type for customers requiring simple operations.

Features and Applications
QKL-B1T low flow electro pneumatic pressure regulator have selections of three output pressure range- 2 bar, 4 bar, 8 bar. With the 2 bar version, it is possible to customize the pressure range to lower value. This features ultra-high resolution of 0.0005 bar, ultra-high stability and quick response time. This electro pneumatic pressure regulator has been widely used in the microfluidics industry in world-leading US medical device manufacturer, and it is also popular amongst dispensing and dosing industry.

QKL-B3 is the high flow version of 8 bar electronic pressure regulator valve. Having an extra volume booster provides a higher flow to the application and allows dynamic working conditions. It offers a high accuracy of 0.1 – 0.25%, high repeatability, and flow rate of 1200 L/min. Many have used QKL-B3 to control pressure in a large closed tank applications encompass semi-conductor testing equipment, dry-process equipment, and manufacturing equipment.

QKL-B3-A is the economic high flow version of electronic pressure regulator valve where the customers have simple applications of pressure regulation. It features quick pressure switch time, high flow, and economic. There is a major application of this electro pneumatic pressure regulator in low pressure gas control in laser cutting machine.

Working Principle
An electronically controlled pressure regulator consist of one high speed processing electronic board, one air pressure transducer, one normally closed solenoid valve to allow air inlet, and one normally closed solenoid valve to allow air exhaust. When the electronics receive electronic signal (0-10V, 4-20mA or digital) from the controller, it will command the solenoid valve to open to allow air inlet into the electronic pressure regulator. The in-built air pressure transducer received senses the pressure and converts it to digital signal. The electronic will compare the set signal with the output pressure. If one is higher than the other, it will command either inlet valve or exhaust valve to operate. This PID loop of working principle will stop until the set signal equals to the output pressure. This way the electronically controlled pressure regulator can accurate change the output pressure according to customers set command signal.

Advantage / Benefits
Because of the high resolution characteristic of low pressure electronically controlled pressure regulator, it has been used in couple with

1. Air pressure ratio regulator
With the air pressure ratio regulator, the output pressure from the electronically controlled pressure regulator is amplified in ratio with the dome pressure regulator. It is normally 20 times ratio. Because of the amplification, the resolution and stability of the electronic pressure regulator is critical in this chimera. The 2 bar and the 8 bar version has been widely used with different air ratio regulators providing a stable high pressure control regulator up to 210 bar (3000 psig).

2. Volume booster
Low pressure electronically controlled pressure regulator often has low flow rate, limiting the application scenarios. Pairing the regulator with a volume booster (1/2” ~ 2”) high precision volume booster allows accurate control of ultra-high flow rate whilst maintaining fine control in air pressure. It has been used in many blow molding or blowing process applications.

3. Steam pressure / water pressure dome pressure regulator

Electronic control of steam pressure and water pressure is critical in many processing industries, such as food manufacturing or tire manufacturing

4. Back Pressure Regulator

Back pressure regulator can be piloted by electronically controlled pressure regulator to regulate either back pressure or forward flow rate. Our regulator features quick response time and stable set value pressure. Please refer to our website on back pressure regulator.

website on back pressure regulator.

Dome Loaded Regulator Types

Low Pressure Proportional Pressure Regulator


Air Pressure Ratio Regulator

2 bar – 10 bar selections

1: 20 ratio

Volume Booster

0 – 8 bar selections

From 1/2’’ to 2’’ port, 4200 L/min at 3 bar.

Steam Pressure

0 – 8 bar, higher pressure is also available.

Stainless steel material available. Up to 220C

Water Pressure

0 – 8 bar, high pressure is also available.

Fluid type can be pure water to slurry

Back Pressure Regulator

Requiring higher performance regulator, consult for customization.

Used for back pressure control or flow rate control

Table 1. Using electro pneumatic pressure regulator with different types of dome loaded regulator 

1. If I intend to output 0.1 psi of air, what is the maximum inlet air pressure to the regulator ?
A. It is recommended to set inlet air pressure regulator as close to the output air pressure for high resolution control.

2. Can I achieve a resolution control such as 0.3 psi change with volume booster?
A. It is not possible.

3. I need a low flow rate 4 bar electronic pressure regulator, but there is a slight flow rate from the container, would QKL-B1T be suitable?
A. Please provide the flow rate, if it is below 4 L/min, it would be possible. Please remember to inform our application engineer for this special request.

◆ Small Size
◆ High Precision
◆ High Sensitivity
◆ Wide Pressure Range

Industrial application
◆ Laser Cutter
◆ Leak Tester
◆ Tension Control
◆ PET bottle molding machine
◆ Multi-Stage Pressure Control
Type  B1T B3-1 B3-A
Input Signal 0-10V / 4-20mA/ RS485 0-10V / 4-20mA
Output Range 0-2bar
(29 psi)
(58 psi)
(58 psi)
0-8bar (116 psi)
Suggesting Supply Pressure Max 3bar
(43 psi)
(73 psi)
(131 psi)
(73 psi)
(131 psi)
9bar (131 psi)
Max working pressure 9 bar(131 psi)
Monitor Output 1-5V / 0-10V / 4-20mA 0-10V / 4-20mA
Power Supply DC24V (≦4W)
Response 0.8S
Medium Clean compressed air or with 5 μm filter
Repeatability ±0.1% F.S. ±0.25% F.S. ±0.5% F.S.
Hysteresis ±0.2% F.S. ±0.25% F.S. ±0.5% F.S.
Linearity ±0.3% F.S. ±0.5% F.S.
Accuracy ±0.3% F.S. ±0.5% F.S.
Flow Rate 4L/min
525L/min@4bar 1050L/min@8bar 1050L/min@8bar
Temp. Range(Operating) 0-70⁰C ( 32-158 ⁰F)
Port Size G1/8" G1/4"
Manifold Material Aluminum
Electrical Connection M12 Connector(2m)
Ingress Protection IP 65
Life Cycle Over 1 Billion Times
Weight 420 g 550 g 430 g
Series Type   Input Signal   Monitor Output   Mounting Bracket   Pressure and Flow   Display Unit
QKL- B1T - E - C - M - P8 - U
  B1T: Low flow with internal feedback   **E: 0-10V   C:0-10V   M:M type   For B1T, B2T
P2:0 - 2 bar, 8LPM
P4:0 - 4 bar, 10LPM
P8:0 - 8 bar, 20LPM
B2T: Low flow with external feedback A: 4-20mA A:4-20mA L:L type U:bar
B3-1: High flow with internal feedback R: RS485 Modbus D:1-5V   For B3-1, B3-2
P4:0 - 4 bar, 320 LPM
P8: 0 - 8 bar, 640 LPM
B3-2: High flow with external feedback        
*B3-A: High flow with internal feedback       For B3A
P8:0 - 8 bar, 640 LPM

*B3-A is an economic type, only with 8 bar. B3-A does not have RS485 modbus interface and does not have 1-5V monitor output.
** For Command Signal type 0-10V, the minimum driving current is 50mA.
★Please consult us for customized pressure range.

The wiring diagram shows from top view.

No. Color Function
1 Blue 24V DC Power (-)
Command (-)
Output monitor (-)
2nd loop transducer 0 -10 V (-)
2 Brown 24V DC Power (+)
2nd loop transducer 4 - 20 mA (+)
3 Black Monitor output (+)
4 White 0-5 V Command (+)
0-10 V Command (+)
4-20 mA Command (+)
5 Gray RS485(D-)
6 Green 2nd loop transducer 0 -10 V (+)
2nd loop transducer 4 - 20 mA (-)
7 - -
8 Red RS485(D+)

** Warning: Do not rotate the connection socket when connected, to avoid damage to the internal sensor.

Product Precautions

The valve can be mounted in any position. For very low pressure control, works best when mounted upright.
And Ensure a minimum closed end volume of 40c.c. to allow proper functioning.

※Preparation Before Piping
Before piping is connected, it should be thoroughly blown out with air (flushing) or washed to remove chips, cutting oil and other debris from inside the pipe.
Wrapping of Sealant Tape
When screwing together pipes and fittings, etc., be certain that chips from the pipe threads and sealing material do not get inside the piping. When sealant tape is used, leave 1.5 to 2 thread ridges exposed at the end of the threads.

Operating Environment
  1. Do not operate in locations having an atmosphere of corrosive gases, chemicals, sea water, or where there will be contact with the same.
  2. In locations where the body is exposed to water, steam, dust, etc., there is a possibility that moisture or dust could enter the body through the EXH port, solenoid valve EXH port and/or built-in regulator EXH port, thereby causing problems.
  3. In locations which receive direct sunlight, provide a protective cover etc.
  4. In locations near heat sources, block off any radiated heat.
  5. Employ suitable protective measures in locations where there is contact with water droplets, oil or welding spatter, etc.

Air Supply
  1. Compressed air, nitrogen, oxygen or argon can be used as a fluid.
  2. Do not use compressed air which includes chemicals, synthetic oils containing organic solvents, salt, or corrosive gases, etc., as this can cause damage or malfunction.
  3. If oxygen is used as the fluid, it can lead to serious and unforeseen risks. However, it is possible to manage and control the risk of hazards and economic loss. In order to use the product safely, it should only be handled by personnel with appropriate knowledge, with support from a suitably qualified specialist.
  4. Oxygen gas increases the susceptibility of substances to burning; Oxygen gas can be ignited by frictional heat and static electricity. If oxygen is ignited, the metal and seal materials burn. Therefore, flush the piping thoroughly and mount a suitable filter to prevent foreign matter such as metal powder and dust from entering the product.
  5. Take safety measures by installing safety devices (e.g. a circuit that stops the supply of oxygen gas) to prevent fire and explosion in the event of failure, taking flameproof safety standards into consideration.
  6. Since there are some exhaust ports on the product, connect the piping in order to exhaust oxygen. Do not block the exhaust port.

KaoLu Ent. Co. Ltd. products are warranted to the original purchaser only against defects in material or workmanship for 6 months from the date of manufacture. The extent of KaoLu’s liability under this warranty is limited to repair or replacement of the defective unit at KaoLu’s option. KaoLu shall have no liability under this warranty where improper installation or filtration occurred.