Seals cartridge

The seal cartridge shall be removable without disturbing the driver. 

A fermentation vessel holds 40 m of liquor that must be kept sterile. Wholesale price of the product is 200/m. Because of the consequences of contamination, an expensive mechanical seal, costing 3000, is installed. Dynamic run-out at the seal is greater than expected, however, and occasionally the product becomes contaminated. This happens on average once a year and a fresh seal cartridge costing 2000, is installed. Lost production is quickly made up when a new seal is installed. 

Attached to the head cap assembly is a sealed cartridge of liquid carbon dioxide which is pierced when the operating lever is depressed, so pressurising the cylinder. Control of discharge rate is by the operating lever... 

Alternatively, portable eyewash units come in many varieties to meet nearly any facihty s needs. They deliver water, saline solution or 100 percent sterile saline at room temperature for safe and comfortable flushing. The fluid in sealed-cartridge devices boasts the longest shelf life and, therefore, requires the least frequent maintenance, and portable units with buffered saline solution more closely match the pH of the eye to protect it during flushing. 

Symmetrical T-groove (SMT) Bidirectional face pattern. The GASPAC seals use bidirectional technology. The SMT also provides increased protection with a unique bidirectional T-groove face design, and can operate in a clockwise or cotmterclockwise rotation. This attribute provides optimum protection from reverse rotation. It also reduces the need for separate spare seal cartridges for each end of a beam-t3 e compressor, because the same seal can operate in either end of the compressor. See Fig. S-5. 

Economic Aspects. Lithium metal is available commercially in ingots, special shapes, shot, and dispersions. Ingots are sold in 0.11-, 0.23-, 0.45-, and 0.91-kg sizes. Special shapes include foil, wire, and rod. Lithium is available in hermetically sealed copper cartridges and in sealed copper tubes for use in treating molten copper and copper-base alloys. Shot is sold in 1.19—4.76 mm (16—4 mesh) sizes. Lithium dispersions (30% in mineral oil) of 10—50-p.m particle size are used primarily in organic chemical reactions. Dispersions in other solvents and of other size fractions can be suppHed. 

Parallel-Leaf Cartridge. A parallel-leaf cartridge consists of several flat plates, each having membrane sealed to both sides (Fig. 13). The plates have raised (2—3 mm) rails along the sides in such a way that, when they are stacked, the feed can flow between them. They are clamped between two stainless-steel plates with a central tie rod. Permeate from each leaf drains into an annular channel surrounding the tie rod (33). 

Cartridges are inserted in series into plastic or stainless-steel tubular pressure housings of square cross section (Fig. 14). Feed flows parallel to the leaf surface. A permeate fitting secures each cartridge to the housing wall, which allows permeate egress and faciUtates sealing between concentrate, atmosphere, and permeate channels. 

Spiral Wound. A spiral-wound cartridge has two flat membrane sheets (skin side out) separated by a flexible, porous permeate drainage material. The membrane sandwich is adhesively sealed on three sides. The fourth side of one or more sandwiches is separately sealed to a porous or perforated permeate withdrawal tube. An open-mesh spacer is placed on top of the membrane, and both the mesh and the membrane are wrapped spirally around the tube (Fig. 16). 

Spiral-wound cartridges are inserted ia series into cylindrical pressure vessels. Feed flows parallel to the membrane surfaces ia the channel defined by the mesh spacer which acts as a turbulence promoter. Permeate flows into the center permeate-withdrawal tube which is sealed through the housing end caps. 

Stuffing Box with Mechanical Seal. Mechanical seal shall he of the (single inside) (single outside) (double inside) (cartridge) type and (balanced) (unbalanced). 

To this day, balanced mechanical seals using o-rings are the standard in industry. Meehanical seals eontinue to evolve in sealing face technology, computer design, finite element analysis, cartridge designs, split seals, double or dual seals, and dry gas seals. 

Cartridge mechanical seals are designed so that the rotary and stationary elements, the springs and secondary seals, the gland, sleeve and all accompanying parts are in one integral unit. It installs in one piece instead of the numerous individual pieces. 

Some cartridge seal models have accompanying re-build kits. 

Cartridge Seal designs comply with most pump standards like ... 

Here is an illustration of a typical cartridge mechanical seal mounted on a shaft in the seal chamber of the pump (Figure 13-18). 

The easiest way to prevent many unplanned premature seal failures is to use balanced o-ring cartridge designed seals. Most of the seal manufacturers make models incorporating these design features. 

Rarely is a balanced o-ring cartridge seal supplied as standard equipment with a new pump. It s thought that they cost too much and will raise the sale price of the pump. 

Although the balance feature, o-rings, and the cartridge concept were discussed in detail in the previous chapter, here is a brief review why this seal design will give your pumps their best chance for extended leak-free service with reduced maintenance costs. 

The Cartridge Concept - has every component part of the sealing system in one unit. They re easier and faster to install and don t require total pump teardown. Most come with additional control ports and rebuild kits. 

For most applications, the balanced, o-ring cartridge seal will adequately handle every pump, liquid, and condition in a modern industrial process plant. There are, however, some industrial pumping applications that will present problems to even the best of mechanical seals. Should one of these applications cause the seal to give less than desirable performance, the next step to take in extending the service life of the seal (and ultimately the pump) is to install some type of environmental control to protect and isolate the seal components from the fluid. Let s consider some difficult sealing applications. 

Very High Pressures Use balanced o-ring cartridge seals up to about 500 psi. Above 500 psi use the tandem double seal with the barrier fluid pressurized at / the seal chamber pressure. Remember as pressure goes up the o-rings will extrude and metal parts will distort. Use a torsion balanced seal. 

The seal unit located at each end of the multistage compressor rotor is installed as a cartridge. The cartridge has positive locating features to permit proper placement on installation. It normally includes a provision to ensure that cartridges are not interchanged from the intended end. This is to prevent reverse rotation on the unidirectional configurations. 

Cartridge seals are set at the factory and installed as complete assemblies. These assemblies contain spacers that must be removed after the seal assembly is bolted into position and the sleeve collar is in place. 

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