常关, 平衡锥阀, 逻辑单元 - 先导打开
- 当口1和口2处压力为5000 psi (350 bar)、外泄口通油箱且先导口处达到最小先导压力300 psi (20 bar)时，独特的平衡结构将提供可预测的切换。
- 口1和口2之间的泄漏速率非常低，通常来说在5000psi时，泄漏速率小于10滴/分钟（即在350bar时，小于0,7 cc/min）
- 当先导压力低至145 psi（10 bar）以下时，阀将回座。
- 所有端口都可以接受5000 psi (350 bar)的压力。
|通流能力||30 gpm120 L/min.|
|最大操作压力||5000 psi350 bar|
|切换阀所需最小先导压力||300 psi20 bar|
|110 SUS (24 cSt)下的最大泄漏||5 drops/min.@1000 psi0,3 cc/min.@70 bar|
|Pilot Volume Displacement||.02 in³0,33 cc|
|阀头部安装六角尺寸||1 1/8 in.28,6 mm|
|阀安装扭矩||45 - 50 lbf ft61 - 68 Nm|
|Seal kit - Cartridge||Buna: 990202007|
|Seal kit - Cartridge||Polyurethane: 990002002|
|Seal kit - Cartridge||Viton: 990202006|
Direct acting valves are used to prevent over pressure and pilot operated valves are used to regulate pressure. If you are unsure, use a direct acting valve. Sun's direct acting valves are very fast, dirt tolerant, stable, and robust. Sun's pilot operated valves are moderately fast, they have a low pressure rise vs. flow curve, and they are easy to adjust.
Because of the very high ratio, the COFO has limited capacity. The discharge path is across a .050 inch (1,3 mm) diameter orifice. If you have large accumulators combined with low precharge pressures, this may not discharge the energy quickly enough. Using the COFO XDN cartridge in conjunction with an LODA XDN will provide capacity for larger applications.
There are exactly 250 Sun drops in a cubic inch or 15 in a cc.
The LH*A family of valves has been optimized to be used in a package to provide a power source for hydraulic tools. We can quantify the performance of the valve in static conditions but we cannot tell you how it will do in your application.
For instance: You want to use the valve as a compensator for a load-sense power steering package. When you are steering the machine and raising an implement, the valve is in a bypass mode (throttling on the bypass side). When the implement actuator bottoms out, pressure jumps to maximum and now the valve needs to change to the restrictive mode. Since the LH*A is balanced against pressure on the bypass side the only thing moving the spool is its own spring. The time this takes is dependent on where the spool was to begin with and where it has to go.
During this transition the steering will see the pressure differential across it suddenly change from about 150 psi (10 bar) to a system pressure of say 3000 psi (200 bar) and suddenly back down to about 150 psi (10 bar). When this scenario was described to me it was termed the broken thumb syndrome.
Sun does not and cannot provide technical support for this type of application. The valve has been successfully used in similar applications. What is necessary to make it work is up to whoever is doing the application.
The valve was developed originally to power demolition hammers. The hammers are aftermarket accessories that are mounted on a large variety of excavators. The "hammer" circuit provides a method of tapping into the existing hydraulic system of the excavator, turning the tool on and off, controlling flow, and limiting pressure.
Every manufacturer of hammers has very specific needs as far as flow and pressure and there is a large disparity of hydraulic systems in the excavators. For this reason, Sun has never had a catalog package for this circuit.
Sun does not and cannot provide technical support for "hammer valve" installations.
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