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If you work with industrial filtration, you are likely familiar with the workhorse of the industry: the stainless steel filter housing. Essentially, it is a durable enclosure—usually crafted from stainless steel or engineered plastics—designed to house either a filter bag or a filter cartridge. Both bag and cartridge housings play critical roles in processing facilities, ensuring that liquids and gases are free from unwanted particulates.
But while they may look similar at a glance, the way they operate and the applications they suit best are quite different. Selecting the right one comes down to understanding these key distinctions. In this article, we break down the fundamental differences between bag filter housings and cartridge filter housings, giving you the clarity you need to make the right call for your specific process.
Before we dive deep, here is the quick takeaway:
Choose a Bag Filter Housing if: Your liquid is dirty, you have high flow rates, and you need to change filters fast.
Choose a Cartridge Filter Housing if: You need fine filtration, you are dealing with high heat or chemicals, or you want a reusable element.
Now, let’s break down why.
The type of contaminant in your liquid is the biggest factor in this decision.
If your goal is to remove tiny particles to make a liquid “polished” or “bright”—for example, in pharmaceutical production, fine chemicals, or beverage clarification—you need a cartridge housing.
Cartridge housings are designed to hold elements that provide depth or surface filtration down to 0.1 microns. They excel at trapping very small particles consistently. If you try to put a fine micron-rated bag in a housing, you risk low flow and frequent blow-outs.
If you are straining out large particles, like scale from pipelines, sediment from river water, or agglomerates from mixing, a bag housing is your friend.
Bags are like large buckets. They have a high open area and are designed to capture a high volume of solids (dirt holding capacity) without plugging up instantly. If your liquid looks muddy, start with a bag.
Flow rate is often the deciding factor for plant managers.
Cartridge Housings usually require multiple elements to achieve high flow rates. A standard 10-inch cartridge might handle 5-10 GPM (gallons per minute). To reach 100 GPM, you might need a housing that holds 10 or 20 cartridges. This works, but it means a larger, heavier housing and more spare parts to keep in stock.
Bag Filter Housings are flow rate champions. A single #2 size bag (about 7″ x 32″) can easily handle 100-150 GPM or more, depending on the viscosity. If you need to move a lot of liquid quickly and the filtration doesn’t need to be ultra-fine, a single-bag housing is the most compact and cost-effective solution.
This is where the material of the filter element matters more than the housing (since both housings are stainless steel).
Bag Limits: Standard filter bags are made from sewn materials like polypropylene or polyester felt. These are great for water and many chemicals, but they fail above 180°F (82°C) . Hot oil or high-temperature solvents will melt a standard bag instantly.
Cartridge Advantages: Cartridge housings can accept all-stainless-steel sintered or mesh cartridges. If you are filtering hot gas (up to 500°F), aggressive solvents, or fluids that need steam sterilization, a cartridge housing with metal elements is the only reliable choice. The rigid structure of a cartridge also handles high differential pressure better than a flexible bag.
This is a classic trade-off. You have to look at your budget for time versus your budget for supplies.
Bag Housings save you time.
Changing a bag is simple: Open the clamp, lift the lid, pull the old bag out, drop the new bag in, close the lid. It takes about two minutes. However, you throw that bag away. Over a year, the cost of replacement bags can add up, especially if you are filtering a lot of liquid.
Cartridge Housings can save you money on media (sometimes).
Changing multiple cartridges takes longer. You have to unscrew or pull out each element. However, if you use cleanable stainless steel cartridges, you don’t throw them away. You take them out, wash them (ultrasonically or chemically), and put them back in. The upfront cost is higher, but the long-term consumables cost drops to nearly zero.
To help you decide right now, run through this checklist:
You probably want a BAG housing if:
Your fluid is high viscosity (like syrup or paint).
You have a high volume of solids to remove.
You need a flow rate over 50 GPM.
Your temperature is below 200°F.
You want the lowest possible labor cost for change-outs.
You probably want a CARTRIDGE housing if:
You need to filter below 5 microns.
Your fluid temperature is very high (steam, hot oils).
You are using aggressive solvents.
You want to avoid disposable waste (using metal elements).
Your contaminant level is low, but quality standards are high.
Looking for specific advice? Feel free to browse our selection of [Stainless Steel Cartridge Filter Housings] or [Stainless Steel Bag Filter Housing]. If you don’t see what you need, contact us—we can custom-engineer a solution based on your actual operating conditions.
