Why use an RDVF?
- The rotary drum vacuum filter is a very versatile liquid/solid separation device. It is used where a continuous separation of a solid from a liquid stream is desired. It can be used in process applications where the solid is the product or where the liquid is the product (and sometimes when both phases are the product). In wastewater applications it can be used to dewater a variety of sludges or to clarify wastewater.
Is there an easy test to tell if an RDVF is right for an application?
- A simple Buchner funnel test will generally determine if the use of an RDVF is feasible. Further testing using a test leaf can be done to simulate the operation of the RDVF under specific operating conditions.
Can an RDVF be used in a batch process?
- Yes, although the filter operates as a continuous separation device, it can be used in batch processes. In these cases, the filter would be operated intermittently as needed to filter a batch of feed slurry.
When is cake washing used?
- Cake washing is used when a given cake purity is required. It is also used to improve extraction of liquid products or dissolved materials from the filter cake. Lab or pilot testing can be used to determine the effectiveness and efficiency of cake washing on an RDVF.
How is the correct size and style of cake discharge determined?
- Lab testing is often the best way to determine the correct filtration characteristics of a given material. In many cases, an RDVF has been previously installed or tested for the same or a similar application. This provides a good starting point in selecting equipment.
What designs are available?
- The design of the RDVF can be changed to suit specific needs for a given application. Various types of cake discharge mechanisms are used depending on the characteristics of the filter cake. Our equipment can be constructed of a variety of materials including carbon steel, stainless steel, plastic, Hastelloy, or titanium. Special material finishes for food or pharmaceutical applications can also be specified.
What if my process produces hazardous vapors?
- Designs are available for applications requiring vapor containment. Vapor-retaining hoods can be used much like the hood in a lab. Completely sealed, vapor-tight designs are used where absolutely no leakage is permitted.
What other auxiliary equipment is needed?
- Generally items required are: vacuum pump(s), filtrate pump(s), and vacuum/filtrate receiver. Also required in some cases are feed or drain pumps and precoat or chemical prep tanks with mixers. Depending on customer needs, cake handling equipment can also be provided. Auxiliary equipment can be provided by K-Sfor a complete system including controls and instrumentation.
What utilities are required?
- Electric power is required to run the filter drives as well as the vacuum pump and the filtrate pump. Water is needed as seal liquid for the vacuum pump and also for cloth wash and sometimes cake wash depending on the application.
How much operator attention and maintenance are required?
- The RDVF is essentially a hands-off machine that requires very little operator attention. Also, it runs at a very slow speed (typically between 0.25 to 1.0 rpm). This means that it will generally operate trouble free with very little maintenance. Maintenance usually involves lubrication of drives and bearings and occasional changing of filter cloth and replacement of wear items.
How much do spare parts cost?
- It is difficult to give a specific cost since there are many sizes and designs of RDVFs, however, spare parts costs are generally low on a yearly basis. Replacement filter cloth is the most common spare part. Other items requiring yearly maintenance include certain wear items on the filter valve and the cake discharge assembly.
What technical service is available?
- Technical service is available for installation and start-up of new equipment. Existing units can also benefit from a service visit to assist in optimizing performance. Contact us for a service proposal.
Are pilot filters available?
- RDVF pilot units are available for rental. The filters have 316SS wetted parts and can be fitted with a cake discharge assembly suited to the application.