2-way cartridge valves, directional functions LCT (high-pressure)

Description

• High-pressure series
• Size 16 … 63
• Component series 3X
• Maximum operating pressure 1000 bar
• Maximum flow 3500 l/min

Features

• Valve poppet with or without damping nose
• 2 area ratios
• 2 different cracking pressures
• Shaft sealing by default
• Special control spools for check valve circuit

Product description

2-way cartridge valves are elements that have been designed for a compact block design. The cartridge valve type LCT is inserted into a special receiving hole in the control block and closed by a control cover type LFT. The control cover establishes the connection between the spring chamber of the cartridge valve and the pilot control valves. This enables implementation of pressure, directional and throttle functions – also in combination.

The main components of 2-way cartridge valves are the cartridge valve (8) and the control cover (2) with different functionality.

The cartridge valve (8) consists of a socket (3) with sealing package (4), control spool (5) and closing spring (6).

The control cover (2) seals the cartridge valve to the outside.

Besides simple control cover functions with external pilot oil supply, version "LFT . DBW2" is also suitable for complex switching functions thanks to its default directional valve connection surface. The connection surface is always closed pressure-tight (1). Suitable switching and proportional servo valves can be connected.

The relief pressure is set at the cartridge (7).

Due to structural-inherent requirements, some control cover versions feature high-pressure fittings leading to the outside. These are assigned a leakage bore L for indication of leakage at the HP fitting.

These ports are not suitable for external pilot oil supply.

Function

Passively controlled 2-way cartridge valves operate depending on the pressure ratio at working ports A and B. This results in three important pressurized surfaces for the function A1, A2, A3. The area at the valve seat A1 is defined as 100%. Depending on the version, the annulus area A2 realized by grading is 0%, 7% or 50% of area A1. The area A3 is identical to the sum of areas A1 + A2.

At pressure function, the area is A2 = 0. Respectively, the area is A3 = A1.

For check valve circuits, a 7% control spool with internal pressure feedback is available This way, the set-up of the block becomes less complex as external pressure feedback into the spring chamber via the pilot oil port X is not required (see "Circuit examples")

In general, the following applies:

The areas A1 and A2 are effective in opening direction. The area A3 and the spring are effective in closing direction. The direction of action of the resulting force from the opening and closing forces determines the working position of the 2-way cartridge valve.

Type code

Technical data

general

hydraulic

(For applications outside these values, please consult us!)

Diagrams/characteristic curves

(simulated with HLP46, ϑOil = 40 ±5 °C)

Δp-qV characteristic curves

Version "D"

Δp-qV characteristic curves

Version "E"

Δp-qV characteristic curves

Version "D"

Δp-qV characteristic curves

Version "E"

Notice:

The specified characteristic curves were simulated with 100% control spool stroke and recommended socket alignment (see drawing) and validated by measurement result. The basis was an installation geometry with ØD3* (see "Dimensions") and a simulation model according to ISO 4411/2008-10-01.

Recommended socket alignment

Bar on bore

Symbols/Circuit diagrams

Version
"A.E"	"A.D"	"B.E"	"B.E./.B…"

Dimensions

Installation bore

Dimensions in mm

Project planning information

• 2-way cartridge valves may only be assembled and commissioned by trained specialists.

• The essential valve components are coordinated with each other at the factory and marked accordingly. In case of faults, the complete valve assembly must be replaced.

• Use of the "depressurized circulation" function for decompression tasks is somewhat limited and should not be activated at maximum operating pressure.

Information

Valve assembly components

Cartridge valve

The cartridge valves are hydraulically controlled via the two working ports A and B and via the spring chamber (supply via the control cover or internally via control spool bore). These assemblies are available in NG16 to 63.

All offered versions are fitted with shaft seals. This way, internal leakage between the spring chamber and port B is prevented.

Control cover

The control cover (2) can lead up to two pilot oil ports on the block side to internal components or additional externally mounted valve assemblies. Via the circuitry of the spring chamber of the cartridge valve (1), various circuit variations can be implemented.

All control covers have relief grooves at the bottom side. Failure of the internal seals is quickly and clearly indicated. On the top of the control cover, leakage at the HP fitting (4) can be identified at the leakage bore L (3) if applicable.

Pilot control valve (not included in the scope of delivery)

At control covers for set-up of a directional seat or pressure valve, the porting pattern is realized according to ISO 4401.

Multi-function cover "LFT_DBW"

By default, this cover is delivered with a connection surface for a pilot control valve. The connection surface is always closed with a pressure-tight blind plate.

By selection and assignment of the internal pilot oil channels, various switching functions can be implemented in addition to pressure functions.

Ordering codes

Downloads

2-way cartridge valves, pressure and directional functions Data Sheet | RE21045 | 2021-08-01 | English, United States | PDF | 1.2MB Product Groups: 2-way cartridge valves Type LCT (cartridge valve); type LFT (control cover)