PST8/21N-K1/K PTH-250/20E1-K10 PTH-400/20E1-K10 DUPLOMATIC Pressure Switch 630 bar

Product Overview

The PS/PST/PTH series pressure switches and pressure transmitters are precision pressure control and measurement components engineered by DUPLOMATIC (Italy) for industrial hydraulic and mobile machinery applications. The PS/PST series are electro-hydraulic piston-type pressure switches that actuate an electrical contact when the system pressure reaches the set value—system pressure acts on a piston, compressing a spring and triggering a microswitch. The PTH series are pressure transmitters based on strain gauge principles, converting pressure signals into standard 4-20mA or 0-10V analog outputs.

The PS/PST series covers multiple sizes including PSP2/4/6/8 and PST2/4/6/8, offering 4 pressure adjustment ranges (35-140-350-630 bar) with subplate mounting or 1/4″ BSP threaded connections. Standard configuration includes adjustment knob with pressure scale. The PTH series offers four rated pressure options (40, 100, 250, and 400 bar), featuring AISI 316L stainless steel wetted parts and withstanding extreme media temperatures from -40°C to +120°C.

Our complete range of DUPLOMATIC pressure switches and transmitters strictly adheres to OEM technical standards, achieving 100% direct interchangeability with original components. Every unit undergoes 100% simulated operating condition bench testing prior to shipment, ensuring performance parameters are fully consistent with genuine DUPLOMATIC products. Direct replacement significantly reduces equipment downtime and maintenance costs.

⚠️ Brand and Model Attribution Note:

• PSP4, PSP6, PST8/21N-K1/K belong to the DUPLOMATIC PS/PST series piston-type pressure switches

• PTH-250/20E1-K10 and PTH-400/20E1-K10 belong to the DUPLOMATIC PTH series pressure transmitters

• The original title references “PS PT PSP PST PTH” which are DUPLOMATIC pressure control product series codes

⚠️ Model Code Decoding:

• PSP / PST = Piston-type Pressure Switch

• 2/4/6/8 = Size code (corresponding to different pressure ranges and port sizes)

• 21N = Design series and seal material (N = NBR)

• K1/K = Electrical connection and contact configuration code

• PTH = Pressure Transmitter

• 250 / 400 = Rated pressure (bar)

• 20E1 = Design series and output signal (E1 = 4-20mA)

• K10 = Electrical connection configuration code

Technical Specifications 

PST8/21N-K1/K

• Product Series: DUPLOMATIC PST series piston-type pressure switch

• Model Code: PST8/21N-K1/K

• Brand: DUPLOMATIC

• Product Type: Electro-hydraulic piston-type pressure switch

• Pressure Adjustment Range: 20 – 630 bar

• Maximum Pressure Resistance: 650 bar

• Pressure Adjustment Stages: 4 options (35 / 140 / 350 / 630 bar)

• Electrical Contact: Electrical changeover contact

• Electrical Connection: DIN 43650 square connector

• Sealing Material: NBR

• Adjustment Type: Rotary knob with pressure scale

• Mounting Type: Subplate mounting or 1/4″ BSP thread

• Operating Temperature Range: -20°C to +80°C

• Compatible Hydraulic Fluids: ISO 6743-4 HL/HM

• Ingress Protection: IP65 (DIN connector version)

PSP Series (General Specifications)

• Product Series: DUPLOMATIC PSP series piston-type pressure switch

• Models Covered: PSP2/21N-K1/K, PSP4/21N-K1/K, PSP6/21N-K1/K, PSP8/21N-K1/K

• Product Type: Electro-hydraulic piston-type pressure switch

• Maximum Operating Pressure: 650 bar

• Pressure Adjustment Range: 35 – 140 – 350 – 630 bar (4-stage adjustable)

• Mounting Type: Subplate mounting or 1/4″ BSP thread

• Seal Type: NBR (N) or FPM (V)

• Operating Temperature Range: -20°C to +80°C

• Compatible Hydraulic Fluids: ISO 6743-4 HL/HM

PTH-250/20E1-K10

• Product Series: DUPLOMATIC PTH series pressure transmitter

• Model Code: PTH-250/20E1-K10

• Brand: DUPLOMATIC

• Product Type: Pressure transmitter (strain gauge type)

• Rated Pressure: 250 bar

• Maximum Dynamic Pressure: 187.5 bar

• Maximum Operating Pressure: 500 bar

• Burst Pressure: 1000 bar

• Output Signal: 4 – 20 mA (E1 version)

• Supply Voltage: 10 – 28 VDC

• Maximum Current Consumption: ≤ 23 mA

• Response Time: ≤ 1 ms

• Media Temperature Range: -40°C to +120°C

• Temperature Drift (0-100°C) : ≤ ±1%

• Wetted Parts Material: AISI 316L stainless steel

• Housing Material: AISI 304 stainless steel

• Ingress Protection: IP65 (DIN connector) / IP67 (M12 connector)

• Weight: Approx. 0.1 kg

PTH-400/20E1-K10

• Product Series: DUPLOMATIC PTH series pressure transmitter

• Model Code: PTH-400/20E1-K10

• Brand: DUPLOMATIC

• Product Type: Pressure transmitter (strain gauge type)

• Rated Pressure: 400 bar

• Maximum Dynamic Pressure: 300 bar

• Maximum Operating Pressure: 800 bar

• Burst Pressure: 1400 bar

• Output Signal: 4 – 20 mA (E1 version)

• Supply Voltage: 10 – 28 VDC

• Maximum Current Consumption: ≤ 23 mA

• Response Time: ≤ 1 ms

• Media Temperature Range: -40°C to +120°C

• Temperature Drift (0-100°C) : ≤ ±1%

• Wetted Parts Material: AISI 316L stainless steel

• Housing Material: AISI 304 stainless steel

• Ingress Protection: IP65 (DIN connector) / IP67 (M12 connector)

• Weight: Approx. 0.1 kg

Key Technical Advantages

1. Piston-Type Mechanical Structure for High-Reliability Pressure Switching
The PS/PST series features a piston-type mechanical structure where system pressure acts directly on a piston, compressing a spring to actuate a microswitch. Unlike electronic pressure switches, the purely mechanical structure does not require external power for pressure detection and contact switching, delivering exceptional reliability and immunity to electromagnetic interference—ideal for industrial environments with stringent EMC requirements.

2. 4-Stage Wide-Range Pressure Adjustment for Flexible Adaptation
The PS/PST series offers 4 pressure adjustment ranges (35 / 140 / 350 / 630 bar), with precise set-point adjustment via a rotary knob with integrated pressure scale. Standard configuration includes adjustment knob with pressure scale—no additional tools required for on-site setting.

3. Ultra-High Pressure Resistance and Multiple Mounting Options
The PS/PST series withstands maximum pressures up to 650 bar, compatible with the vast majority of high-pressure hydraulic systems. Supports both subplate mounting and 1/4″ BSP threaded connections, with seal material options of NBR or FPM, compatible with ISO 6743-4 HL/HM hydraulic fluids.

4. PTH Series High-Accuracy Strain Gauge Measurement with Extreme Temperature Capability
The PTH series pressure transmitters operate on strain gauge principles with electrical circuits manufactured using SMT (Surface Mount Technology) . All wetted components are manufactured from AISI 316L stainless steel with a fully sealed design. Media temperature range spans -40°C to +120°C with temperature drift ≤ ±1% (0-100°C range)—particularly suitable for extreme工况 (operating conditions) with severe temperature fluctuations.

5. PTH Series Fast Response and Multiple Output Options
The PTH series delivers response time ≤ 1 ms, meeting the demanding requirements of dynamic pressure measurement. Offers both 4-20mA (E1 version) and 0-10V (E0 version) standard analog outputs with reverse polarity protection. Wide supply voltage range (10-30V DC) and ingress protection IP65 (DIN connector) or IP67 (M12 connector)  ensure suitability for diverse industrial environments.

6. 100% Direct Interchangeability and Simulated Condition Testing
All models strictly adhere to DUPLOMATIC original mounting dimensions and interface standards, enabling direct drop-in replacement of original pressure switches/transmitters without piping modification or system adjustment. Every unit undergoes 100% simulated operating condition bench testing prior to shipment, ensuring consistent, stable performance at rated pressure and temperature.

Application Areas

• Hydraulic System Pressure Monitoring & Control: System pressure detection and alarm for hydraulic power units

• Construction Machinery: Pressure protection for excavators, wheel loaders, cranes

• Injection Molding Machinery: Pressure control for injection molding and die-casting machines

• Mobile Machinery: Pressure monitoring and safety protection for mobile equipment hydraulic systems

• Industrial Process Control: Process pressure measurement and control in chemical and metallurgical industries

• PTH Series: Precision pressure measurement applications requiring fast response and analog signal output

• PS/PST Series: Reliable applications requiring purely mechanical pressure switching for on/off control

Expert Maintenance Tips

1. Verify Model and Range Compatibility Prior to Installation
The PS/PST series offers 4 pressure adjustment ranges (35/140/350/630 bar)—confirm that the model’s pressure range covers the system operating pressure. For the PTH series, verify that the rated pressure (40/100/250/400 bar) matches the system maximum pressure. The PTH-400/20E1-K10 has a maximum operating pressure of 800 bar with burst pressure of 1400 bar.

2. PS/PST Series Pressure Setting
PS/PST series pressure switches are set via the rotary knob with integrated pressure scale. Rotate the knob slowly while monitoring a pressure gauge to confirm the switching point. Never exceed the 650 bar maximum pressure resistance. Lock the adjustment mechanism after setting to prevent set-point drift from vibration.

3. Electrical Connection Precautions
PS/PST series feature DIN 43650 square connector standard electrical connections. Verify supply voltage and contact capacity match prior to wiring, and observe correct use of contact type (normally open/normally closed). PTH series feature DIN connector or M12 connector with 10-30V DC supply and reverse polarity protection.

4. Installation Torque and Sealing
PS/PST series support 1/4″ BSP threaded connections or subplate mounting. For threaded connections, use PTFE tape or thread sealant—apply sparingly to prevent sealant material from entering the valve body. Tighten to torque values specified in DUPLOMATIC technical manuals to avoid body distortion or thread damage from over-tightening.

5. System Cleanliness Management
PS/PST series piston-type pressure switches feature relatively tight internal clearances and demand adequate oil cleanliness. Recommended system cleanliness: ISO 4406 Class 19/17/14 or higher. PTH series sensor diaphragms are precision components—thoroughly flush system piping prior to installation to prevent debris from damaging sensing elements.

6. PTH Series Periodic Calibration
PTH series pressure transmitters should undergo zero and span calibration checks every 12 months. If abnormal output signal drift or sluggish response is observed, arrange for servicing or replacement. Transmitters offer IP65/IP67 ingress protection—ensure electrical connections remain properly sealed after installation to prevent moisture and contaminant ingress.

7. Periodic Functional Checks
Perform functional checks every 2,000 operating hours or annually. PS/PST series require verification of switching point accuracy and contact reliability; PTH series require verification that output signal vs. pressure correspondence remains within accuracy specification. If abnormalities are observed, arrange for servicing or replacement.