固定节流口, 流量保险阀
流量保险阀用来使液压驱动器在液压管路破裂的情况下保持位置。此阀可以让油液流出或流入驱动器，但是如果流出驱动器的流量超出此阀的设定值，此阀会迅速关闭。注意：因为此阀响应迅速，此阀对超出设定值的任何瞬态流量都很敏感。
- 客户必须设定流量等级。工厂设定流量精度为用户要求的±10%。
- 当1口流向2口的流量大于阀的设定值时，阀将会关闭。自会有当1,2口的压力相等时，阀才可以再次重置。
- 流量设定必须比系统最大流量还要大25%。用户必须在订货时提供设定流量值。
- 这种滑阀式结构使得泄漏存在。所以执行器的微动将可能存在。
- Sun浮动式的结构可以最大限度地减少由于过大的安装扭矩以及孔型加工的误差所造成的干涉现象。
| 插孔 | T-18A |
| 系列 | 4 |
| 通流能力 | 50 gpm200 L/min. |
| 最大操作压力 | 5000 psi350 bar |
| 110 SUS (24 cSt)下的最大泄漏 | 5 in³/min.@1000 psi80 cc/min.@70 bar |
| 阀头部安装六角尺寸 | 1 5/8 in.41,3 mm |
| 阀安装扭矩 | 350 - 375 lbf ft474 - 508 Nm |
| 型号重量 | 2.90 lb1,30 kg |
| Seal kit - Cartridge | Buna: 990018007 |
| Seal kit - Cartridge | Polyurethane: 990018002 |
| Seal kit - Cartridge | Viton: 990018006 |
NO! Flow fuses are meant to prevent the uncontrolled movement of an actuator in case of hose failure. To avoid false tripping they must be set above the typical system flow, usually 50% above. On a 4 gpm (15 L/min.) circuit the flow fuse may need to be set at 6 gpm (23 L/min.) to avoid false tripping. Hoses do not normally fail totally, they spring a leak. If the hose springs a 5.5 gpm (21 L/min.) leak the flow fuse will not trip. 5.5 gpm (21 L/min.) of hydraulic fluid will feed a fire that would heat a small town in Ohio (Denmark) in January!
It is very, very difficult to predict the transient flows in a system. We say at least 25% above maximum normal system flow and should say 50%. Don’t back yourself into a corner by sizing a flow fuse at the top end of its range unless you can test it. If you have an FQCA in a 4 gpm (15 L/min.) circuit, set at 6 gpm (23 L/min.) and it false trips, you are out of luck. Select an FQEA and leave yourself some room for tuning.
What's wrong is that every time you start to lower your load, you get a flow transient that exceeds the setting of the flow fuse and trips it. Sun's flow fuses are very consistent and very fast.
There are exactly 250 Sun drops in a cubic inch or 15 in a cc.
NO! Flow fuses are meant to prevent the uncontrolled movement of an actuator in case of hose failure.