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NORGREN one-way throttle valve application description

NORGREN proportional valves and dedicated device technology make electrical control of various systems such as gear shifting, steering, braking and working devices of engineering vehicles a reality. It is generally required that the displacement output mechanism be implemented using a proportional multi-valve driver similar to a proportional servo control. Electrical operation has the advantages of fast response, flexible wiring, integrated control and easy interface with computer. Modern engineering machinery hydraulic valves have increasingly adopted electronically controlled pilot-controlled electro-hydraulic proportional valves (or electro-hydraulic switching valves) instead of manual direct Operation or hydraulic pilot control of the multi-way valve. Another significant advantage of using an electro-hydraulic proportional valve (or electro-hydraulic switching valve) is that the number of operating handles can be greatly reduced on the construction vehicle, which makes the cab layout simple, can effectively reduce the operational complexity, and has improved work quality and efficiency. Important practical significance.

The opening area of the two channels of the NORGREN proportional valve can vary from zero to maximum, depending only on the control current. However, the open area ratio of the two channels may be 1:1 (symmetric spool) or 2:1 (asymmetric spool). This is done to accommodate the requirements of asymmetric hydraulic cylinders. At the same speed of a single-rod hydraulic cylinder, the flow rates of the inlet and outlet chambers are different from each other. The median function of the three-position four-way valve, that is, the connection of the oil ports at the natural position in the absence of a signal state, can also take various forms. They also have a significant impact on the performance of the loop. All of the above, in particular, its inlet and outlet simultaneous throttling can bring a lot of different characteristics to the ordinary directional control circuit. In some cases, it is possible to use a normal reversing valve, but a proportional valve using the same mid-range function will be problematic. The most obvious difference is that in the proportional control described above, the area ratio of the two working chambers of the actuator must be adapted to the ratio of the opening area of the control valve.

The valve core of the NORGREN proportional valve can be positioned at any position, that is, the position is steplessly adjustable, and the multi-working position of the proportional valve can be reasonably utilized and used with an appropriate electric controller, using only one proportional directional valve. A variety of functions such as acceleration, deceleration, balance, differential, fast and slow speed can be realized, which greatly simplifies the hydraulic control system. The above features and functions are well used in the Noell crane.

The opening area of the two channels of the NORGREN proportional valve can vary from zero to maximum, depending only on the control current. However, the open area ratio of the two channels may be 1:1 (symmetric spool) or 2:1 (asymmetric spool). This is done to accommodate the requirements of asymmetric hydraulic cylinders. At the same speed of a single-rod hydraulic cylinder, the flow rates of the inlet and outlet chambers are different from each other. The median function of the three-position four-way valve, that is, the connection of the oil ports at the natural position in the absence of a signal state, can also take various forms. They also have a significant impact on the performance of the loop. All of the above, in particular, its inlet and outlet simultaneous throttling can bring a lot of different characteristics to the ordinary directional control circuit. In some cases, it is possible to use a normal reversing valve, but a proportional valve using the same mid-range function will be problematic. The most obvious difference is that in the proportional control described above, the area ratio of the two working chambers of the actuator must be adapted to the ratio of the opening area of the control valve.

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