Core Classification and Working Principle
Radk Hydro is a RT-PSL and RT-PSV load‑sensing proportional multi‑way directional valves manufacturer. We have 2‑series, 3‑series and 5‑series models. These valves are direct replacements for HAWE PSL/PSV load‑sensing proportional multi‑way valves. Our proportional multi‑section valves hold a dominant leading position in the Chinese market. Our customers include world‑class construction machinery manufacturers such as Sany, XCMG, Zoomlion and LiuGong. If you would like to know more about our proportional multi‑section valves, click here.Below are their key classification and working principles.
Classification by pump type
RT-PSL: Works with fixed‑displacement pumps (open‑center circuit). Its inlet section comes with a 3‑way pressure compensator. Extra flow goes to return oil or downstream circuit. It offers fast response yet causes energy loss.
RT-PSV: Works with variable‑displacement pumps (closed‑center circuit). It produces no extra flow loss and delivers lower energy consumption.
Core features
It combines load‑sensing function and proportional control. Flow rate only depends on the spool opening area. Load changes will not affect flow rate. Multi‑spool simultaneous operation is supported.
Common working pressure
For all series, max pressure at pump side: 400 bar. Max pressure at actuator side: 420 bar.
Key Parameter Differences Among the Three Series
The main differences among 2‑series, 3‑series and 5‑series lie in flow rate, port connection, weight and mounting size. These factors are the basis for valve selection.
| Series | Maximum flow at pump side | Max. flow at actuator side | Main port thread(P/R) | Mounting thread | Max. number of working sections |
| 2 Series | 80L/min | 60L/min | G1/2 | M8 | 12 |
| 3 Series | 80,100,200L/min | 120L/min | G1/2,G3/4,G1,G1 1/4 | M8 | 12 |
| 5 Series | 250,300L/min | 240L/min | G1,G1 1/4 | M10 | 10 |
Q&A for Proportional Multi‑Way Valve Selection
Q1: What pump types fit RT-PSL and RT-PSV respectively? What causes their energy consumption difference?
- Suitable pump type: RT-PSL matches fixed‑displacement pump for open‑center circuit. RT-PSV matches variable‑displacement pump for closed‑center circuit.
- Energy consumption difference: RT-PSL uses fixed‑displacement pump. Its 3‑way valve only supplies required flow for actuators. Extra pump flow returns to tank or downstream circuit, which brings energy loss. RT-PSV uses variable‑displacement pump. The pump adjusts its output flow according to total spool opening demand of multi‑way valves. No extra flow wastes. So RTPSL consumes more energy than RTPSV.
Q2: What part keeps flow rate stable against load change for load‑sensing proportional multi‑way valves?
The built‑in 2‑way pressure compensator guarantees stable flow.
The 2‑way pressure compensator adjusts automatically with pressure change from pump side or load side. Its spring sets fixed pressure differential (6 bar / 9 bar). It keeps constant pressure drop across the main spool. Therefore flow to actuator only follows spool opening area, and will not be disturbed by load pressure change.
Besides, flow can be distributed as required during multi‑spool combined action to further stabilize flow performance.
Q3: Which series has the highest max flow at actuator side? What is the mounting thread difference between 5‑series and 2/3‑series?
- 5‑series delivers the highest actuator‑side flow. Normal max flow reaches 160 L/min, and catalog peak value hits 196 L/min. 2‑series max flow is 60 L/min. 3‑series max flow is 100 L/min. Both are lower than 5‑series.
- Mounting thread: 5‑series uses M10 mounting thread. 2‑series and 3‑series adopt M8 thread. Larger M10 thread fits the high‑flow and heavy‑duty structure of 5‑series HAWE replacement multi‑way valve.
Q4: For mining explosion‑proof working condition, should we choose 2‑series or 3/5‑series? Why?
Pick 3‑series or 5‑series.
Reason: The solenoid of 2‑series only supports standard G12 (12 VDC) and G24 (24 VDC). It has no explosion‑proof or coal‑mine safety options. 3‑series and 5‑series support optional G24Ex explosion‑proof solenoid and G24MA coal‑mine‑approved solenoid. They meet temperature and protection requirements for hazardous sites. For explosion‑proof version, ambient temperature ranges from ‑40 ℃ to +40 ℃. Click here to learn more about our explosion‑proof proportional servo valves. They fully fit mining and other explosion‑prone sites for HAWE PSL/PSV alternative multi‑way valves.
