What is the difference between a monoblock valve and a sectional valve?
A monoblock valve is a fixed-configuration valve with all sections inside a single cast body; it is inexpensive, compact and has few leakage points, but the number of sections cannot be changed. A sectional valve is built by bolting inlet, work and outlet sections together with tie bolts; sections can be added or removed and each section can be customized separately.
The biggest advantage of the monoblock valve is its integrity. With no seals between sections, the risk of external leakage is low, the body is rigid and the cost is more favorable. It is widely preferred on tractor front loaders, tippers and small lifting equipment. Its limitation is clear: the number of sections is set at the factory and you cannot add functions later.
In a sectional valve, each work section is an independent body. What that brings:
- The number of functions can be increased or reduced later.
- Each section can have its own load holding valve, shock valve or a different spool characteristic.
- Parallel or series flow arrangement between sections can be selected.
- A faulty section can be replaced on its own.
The cost: higher price, more seals and therefore more potential leakage points, plus sensitivity to tie bolt torque.
Small valve banks mostly work fine in a parallel arrangement. On equipment such as truck cranes and front loaders, the sectional design is seen more often because different functions have different flow rate and holding requirements.
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