Knife gate valves help you manage slurry flow, even with abrasive materials or solids. Choosing the right valve minimizes blockages, leaks, and downtime.
Kramp stocks Metaltecnica Zanolo (MZ) knife gate valves for agricultural slurry systems, including MZ cast-iron knife gate valves and MZ cast-iron knife gate bidirectional valves. If you're unsure which fits your setup after reading this article, speak to a Kramp product specialist.
When are knife gate valves used in agriculture?
A knife gate valve is a full-flow valve. A blade moves vertically to open or close the line.
In slurry handling, this design is beneficial because:
- The stainless steel blade resists corrosion and cuts through dense or settled slurry.
- The valve seals well when slurry contains solids.
- The compact body fits tight installations on tankers and pump sets.
You typically find these valves on:
- Slurry tankers and umbilical systems.
- Farm digesters and biogas plants.
- Slurry storage tanks, reception pits, and transfer lines.
Which knife gate valve should you choose?
Kramp offers several Metaltecnica Zanolo options, but for slurry systems, MZ cast-iron knife gate valves and MZ cast-iron knife gate bidirectional valves are common. They share the same purpose but differ in sealing, flow direction, and clogging likelihood.
Shop MZ cast-iron knife gate valves
Shop MZ cast-iron knife gate bidirectional valves
Main differences between the two MZ valve types
MZ cast-iron knife gate valves
MZ cast-iron knife gate valves are unidirectional with no discharge. They feature a cast iron body and a stainless steel blade that moves vertically.
You can operate them manually or use an actuator like hydraulic or pneumatic. The EPDM rubber seal sits in a screwed-on sleeve.
(EPDM is a synthetic rubber used in slurry applications because it stays flexible and resists aging in wet and outdoor conditions.)
Slurry pressure from the correct direction pushes the blade against the seal for a tight closure. Plan for regular cleaning, especially if handling thick slurry with fiber.
This type is often chosen for fixed flow direction and cost efficiency.
MZ cast-iron knife gate bidirectional valves
MZ cast-iron knife gate bidirectional valves support two flow directions. Their cast iron body consists of two halves joined with bolts, and the thicker stainless steel blade improves stability under load.
The EPDM seal has a steel core. The valve seals through the full contact between the blade and seal perimeter. With no internal cavities, clogging is less likely when slurry contains solids. Internal guide rings stabilize the blade at medium pressures.
This design suits systems where flow direction can change or clogging risk is higher.
The questions to ask before you decide
Do you need bidirectional sealing?
If your system runs in both directions or may reverse flow, choose MZ cast-iron knife gate bidirectional valves. MZ cast-iron knife gate valves are for one flow direction.
Is clogging likely?
If handling slurry with high solids or settled material, MZ cast-iron knife gate bidirectional valves are safer since they lack internal cavities. MZ cast-iron knife gate valves may need more frequent cleaning.
What maintenance can you manage?
If access is limited, opt for a design less prone to buildup. With regular inspection and cleaning, you have more flexibility.
Do you need extra blade stability at medium pressures?
If installation adds mechanical load on the blade, MZ cast-iron knife gate bidirectional valves have internal guides to reduce unwanted bending.
If you need help matching a Metaltecnica Zanolo valve to tankers, pump sets, or digester lines, contact us. A product specialist can assist with sizing, actuator options, and installation details.
This article is based on content originally published by Metaltecnica Zanolo. The original version can be found here. Content used with permission.
