Brake JZ-7 may be used not only on passenger locomotives but also on freight locomotives. It has the ability to gradually release at passenger locomotive, and directly release at freight locomotive. Brake JZ-7 is able to perform self lapping, namely it may keep automatically pressure constant after brake pipe releasing. Brake cylinder may be automatically charged by air once the brake cylinder leaks out, so it has a good endurance. While emergency braking applied, the brake cylinder may pressurize. In order to suit for long and large train braking, a over-charge position is designed to shorten train pipe, as well as the initial charging and recharging time of auxiliary reservoir. This type of brake may used on various diesel locomotives and electric locomotives.
JZ-7 brake valve for locomotive consists of automatic brake valve, independent brake valve, relay valve, distributing valve, application valve, equalizing reservoir, service reservoir, pressure reduction reservoir, application reservoir, and brake reservoir and so on. The structure of rubber diaphragm and spool valve with O-ring has been adopted in the JZ-7 brake valve, so as to prolong the overhaul cycle. It makes manufacture, usage and repair work more conveniently. Applied a cam to control the actuating mechanism, the automatic brake valve and the independent brake valve make control handle easy to operate and not be effected by temperature. The distributing valve uses two-pressure and three-pressure mixing structure; It has not only graduated release function but also direct release function. So the distributing valve suits for different brake cylinder capacity of modern locomotives and brake reservoir pressure will not vary along with the variety of brake cylinder volume. No matter where the locomotive is in the train, the same of brake reservoir pressure will be received.
Characteristics and Parameters of JZ-7
Performance of automatic braking: Time for initial charge of pressure reservoir of distributing valve from 0 to 460 kPa : 50~60s Time for initial charge of pressure reduction reservoir of distributing valve from 0 to 480 kPa : 55~65s Effective local reduction of brake pipe (KPa): 25~35 4. Local reduction should take effect before brake pipe of the single locomotive reduces pressure to 20 kPa. At the same time, the main valve acts: starting local reduction and brake cylinder lifting pressure 5. Graduated release times after in full service application: not less than 5 times (at the passenger train position) 6. Time for pressure reduction in equalizing reservoir in service application from 500KPa to 360KPa (S): 5~7 7. Max. brake cylinder pressure in full service application (KPa): 340-360 8. Time for build-up of brake cylinder pressure in full service application (S): 5-7 9. Time for release of brake cylinder pressure from 350KPa to 35KPa (S): 5~8 10. Time for exhaust of brake pipe to 0 in emergency application (S): within 3s 11. Max brake cylinder pressure after emergency application (KPa): 420~450 12. Time for build-up of brake cylinder pressure to max. after emergency application (S): 5~7 Performance of independent braking: Highest brake cylinder pressure in full application position (KPa): 300 Time for build-up of brake cylinder pressure from 0 to 280KPa (S): within 3s In running position, time for reduction of brake cylinder pressure from 300Kpa to 35Kpa (S): within 4s
Main Technical Parameters
Air-vacuum Brake JZ-6
Automatic brake valve
A :Automatic Braking : 1 ,Pressure inside braking cylinder:350KPa,time 7-10 seconds. 2 ,Time for reduction of cylinder pressure from the highest to 35KPa: 6-8 s 3 ,Highest pressure of emergency braking cylinder: 450KPa: 4-7s