Document vBLZqyjKNJVmOwoexvepLKnQE

Treat Your Compressor Seals Right Shatt ualb on refrigeration com pressors prevent leakage of (1) gat and oil out of the crankcase and (2) air into ll. Seal* on modern highspeed compressors ere often (he ipring-foaded type, Fig. 1. Another popular design, Fig. 2, uses lempered-ttcel diaphragmi. Pockg*rypo compressor hos motor, storler, one bore, ond is easy to Install (or short or I In both, friction surface it much leu than in a stuffing-box-type teal. In Fig. S, unit hat a bellows element. ' Col) Spring. In (hit type, Fig. 1, (he entire aeal assembly rotates with the SAVE MONEY! service before, the 'price is less than for a new unit. All calculations are based on the price compressor shall. Contact between the established before the unit was deliv seal-lace surface and its mating station ary seal seat forma the running seal joint. Both surfaces are highly finished Rent an Air Compressor ered to the user. Usually about 90% of the rent paid may be applied toward purchase of the compressor. There is so they are smooth and flat, usually a time limit set after which tho i The seal face loosely encircles the aft and it held tight against the sta- By IESUC B SCHRAMM, Secretary, Sduomm, Inc compressor may not be purchased with part of tho rent paid on it. Ill S nary seat by the coil spring. Any gas liquid pressure in the crankcase also ta on seal face, pressing It to the seat, it the spring furnishes main force. ' Seal-face back contacts front of the resilient friction ring. This ring Is iiFCTntRB ars four reosons why you as jTuFoperating engineer may want to rent feitir compressor. These era (1) to Jjftf extra capacity during peak-load For example, monthly rental (or a com pressor can be charged oil for taxes if no resale ol equipment Is planned. Where to Rent. The idea of renting Of course, if you rent a compressor for a long period, there comes a time when money spent for rent equals or is greater than the purchase price of the machine. So be sure to have competent legal advice before entering an agree closely fitted to shaft and prevents leak ISaHodi (2) to prove that type of unit e compressor is (airly new. Usual pro ment to rent an air compressor. III age at this point. Expansion of the ring is restricted by the friction-ring band, ffaf hara in mind is right for the job cedure is lo contact the local distributor Maintenance. Agreement should de |p to maintain production while your for the make of unit you have in mind. fine who is responsible for maintenance. keeping seal tight at all times. Jgjfulsr compressors are down for main- Method of renting or leasing varies from Normally the user must maintain the Diaphragms, Fig. 2, give a positive balance between internal crankcase pressure end asternal atmospheric pres sure. Case-hardened steel collars retain the diaphragms, which are Immersed in oil. Total friction aurface is said to be less than 5% ol the conventional stuf fing-box-type seal. Bellows. Seal nose. Fig. 3, carries ' 8 narrow ring with an accurately fin ished surface that is made to bear against a hardened-steel collar on the . rotating shaft. Collar sealing aurface is afao highly polished. Flange mounts the seel assembly and the bellows pro vides a flexible end gas-tight connection between Binge and seal nose. Spring maintains a firm contact between aeal nose and shaft collar. looks. Shaft seals seldom develop leaks if the compressor is run right. In good operation one of the most impor tant items is the right amount of (ube oil in the eompre&sor crankcase. Keep the oil clean at all limes and be sure It is the grade recommended by compressor Handle its parts carefully because set!, manufacturer. faces must be perfectly smooth ta be"? High-speed Freon compressors squesk effective. Deep scratches or grooves uid- ' or squeal when shaft aeal is dry or ally mean that seat must be replaced or scored. Stop the compressor as soon reconditioned. as you hear noises like this that do not Choosing Seal. Life of a compressor come from drive belts or other parts of seal depends on the basic design, proper' the compressor. Check crankcase oil finish of sealing surfaces and right in- ; ievel immediately- A damaged seal can stallation. Seal must be suitable for abaft ` lead to expensive repairs. speed because there may be many varis- Once e week, during norma! running, lions in a unit suitable for 400 rpm and . stop compressor and check seal lor oil - one built for 1200 rpm. So be most care leaks. If much oil is found on seal ex ful when replacing a seal to see this it terior, teat for refrigerant leaks, using Is right for the speed, pressure, ten- a halide torch. perature, fluid conditions on your job. % Seals like that in Fig. 1 may develop Maintenance. Your first pile in caring-; a slow leak when compressor is first lor seals is cleanliness, just as It i> Hr started. Long storage or lock of oil be ball and roller bearings. Don't unwrap a *, tween sealing surface* it usually the new seal until you have your work area cause. On most jobs, crankcase oil spotless. Store seals only in a clean, dry.- reaches the seal Immediately after unit ploee. Once the seal is installed, check starts, establishes a light seal again. It every week for liquid and gas leaks. ff leak doesn't stop wilfun a short time Seals require little attention other than alter starting the compressor, shut the this; they'll run (or years without unit down and open aeal for inspection. trouble if properly lubricated. in PIANT OPERATION AMO MAINTENANCE SECTION k>Wp aEpinee or repairs, and (4) (or certain one distributor to another. unit at his own expense. But, of course, 'wiparposes. Some distributors operate under a there ts the normal guarantee period Elvira Capacity. Suppose you have a* verbal agreement. Others use letter during which both the manufacturer and Rternment or other short-run contract - agreements covered by a purchase order distributor give the usual service con j&ii. probably won't be renewed, or o from the user. But sueh systems have nected with this type of machine. Care lead once a year or at some other dangers for both user and distributor. less end wrong application by the user Pfar interval. Renting a compressor If user gets into money troubles, dis my save money because you won't havteributor may lose his ownership because |i units for long periods, the unit is bolted down in a bankrupt gtsitlng. |( you're studying a newplant. Proof of ownership is extremely are his responsibility. Types. You couldn't rent a compres sor if units that are easy to install and remove had not been developed. Direct ^rixett or Idea, purchasing one or moreimportant in sueh instances. and V-beli-driven units -from % to ISO fenprestors may be a mistake uotil you To overcome this problem, many dis hp lend themselves to rental. Most man Jjide on pressure, capacity, location, tributors use a retention-title contract, ufacturers have suitable units. Pack {*- Either portable or stationary units ft is recorded in states requiring this, or aged compressors, Fig. 2. are well rented for production tests, other legal steps ere taken, depending suited for rentol. jr-froductlon. Instead of losing all or on local laws. Some builders have receiver, starter, tart of your compressed-air capacity Besides recording the title, rental motor, compressor, aftercoolers tnd sep igriag maintenance or repair of your terms are stated, as is the percent of rent arators all on a single bate for easy repressors, rent a unit. Either portable that can he applied toward purchase of handling. Garage compressors, Fig. 1, ^'stationary, it will keep production the compressor, if the buyer decides be arc often rented. Normal rating runs ^normal while you or the manufacturer wants to keep the equipment. to 15 hp. They are easily shifted. pks on y0ur regular units, Purchase. Most distributors establish When renting, be careful lo consider 'J* Savings. Though the average a resale price when they rent. It is compressor's installation cost. If you BPptlor doesn't have to worry much based on the use unit has had. If new, spend a large sum on a setup, the advan Sp* taxes, he eon help make savings. it carries the list price. If in rental tages of renting msy be wiped out. @L SOMBER 1993 PUNT OPERATION AND MAINTENANCE SECTION 123