CN1270089C

CN1270089C - Dry-type spiral vacuum pump

Info

Publication number: CN1270089C
Application number: CN 02107378
Authority: CN
Inventors: 吉村将士
Original assignee: DAIKO MACHINERY INDUSTRY Co Ltd
Current assignee: DAIKO MACHINERY INDUSTRY Co Ltd
Priority date: 2002-03-18
Filing date: 2002-03-18
Publication date: 2006-08-16
Anticipated expiration: 2022-03-18
Also published as: CN1445457A

Abstract

The present invention provides a dry-type spiral vacuum pump which has the structure that a rotor (a spiral screw thread) is provided with a serrate left spiral screw thread and a serrate right spiral screw thread composed of an out-circle trochoid curve, an Archimedes curve and a circular arc curve; the number of lead of the dry-type spiral vacuum pump is more than two; the inner space of the pump is divided into more than two closed oil chambers by the inner wall of the pump body comprising the spiral rotor, the wall surface of a side box (A) with a crescent discharge port and a spiral sealing line; the spiral sealing line moves as the rotor rotates; the closed oil chambers move to the discharge side from the suction side; the side wall of the pump body is provided with a suction hole communicated with the second closed oil chamber from the discharge side; the position of the suction hole can ensure that the hole is opened for the longest time for the second closed oil chamber; cold air is led to the rotor for cooling; simultaneously, dust, etc., retaining in the pump is discharged. The present invention has the advantages that the oil mixing in the process air can be simply prevented, and exhaust pollution from the vacuum pump to the atmosphere is prevented.

Description

Dry-type spiral vacuum pump

Technical field

The present invention relates to a kind of vacuum pump, especially dry-type spiral vacuum pump.

Background technique

Screw vaccum pump in the past carries out high pressure compressed under the single-stage state, can produce a lot of compression heat, is difficult to keep the gap between the cylindrical of helical rotor or screw thread and pump housing inwall, and causes deadlocked accident; Therefore, inject liquid, play the effect of tightness and heat cooling, be referred to as the wet type screw vaccum pump from the suction side.But, in recent years,, and gradually adopt the screw vaccum pump that is referred to as dry type owing to people abstain to sneak into foreign body in the flow process gas.Because, adopting to add cooling water to the axle center of helical rotor, the sleeve pipe of packing in pump case allows flow of cooling water, pump is made multistage, can reduce the compression ratio of each grade, and interstage cooler being set between at different levels cools off, and has prevented that effluent air temp is too high.

But, add the method for cooling water to rotor shaft, can easily leak because of the axle envelope that cooling water is used, and the sludge in the cooling water or scale remain in easily in the axle and are easy to generate accident.In addition, pump is made multistage method, need very big installing space, interstage cooler etc. are again the reasons that cost is strengthened.And the situation of vacuum pump is cut off the suction side when having to move again, when discharging side the occasion of one-way valve is not housed, and the pressure of discharging side is before being disconnected by the spiral seal line, because the existence of adverse current is discharged side and quite high temperature can be occurred.If load onto one-way valve, this valve easy break-down, the flow process gas of sneaking into foreign matter easily is unaccommodated for vacuum pump.

Adopt control rotor clearance (expansion gap) to prevent the method for deadlocked phenomenon, the leakage that can strengthen the gap reduces the vacuum pump performance: find best gap width, need carry out repeatedly determining after a large amount of tests greatly.

Summary of the invention

The present invention need not complicated experience and technology, not needing to install interstage cooler is set as vacuum pump multistage, and countershaft adds cooling water: and adopt easy method that rotor is cooled off, can cut off the operation of vacuum pump by air, and, can with from the suction side with flow process gas sneak in the pump foreign matter (for example, even the immobilising occasion of a large amount of gases that enters from the suction side), discharge from exhaust port, the effect of killing two birds with one stone is played in the appearance of the faults such as foreign matter of avoiding nipping.

It among the present invention is 2 more than the helical pitch (single screw thread is 2 pitch), by the spiral seal line, there is the wall of the pump side case A of exhaust port will be divided into the grease chamber that closes more than two in the containing space of the rotor helical-screw that forms on the pump inner body wall with the length setting at the rotor screw thread position of spiral type thread vacuum pump; In this closes the grease chamber, should close the grease chamber to second from exhaust port and feed cold air, on pump housing wall, be provided with the inlet (cold air oppositely enters the mouth) of introducing cold air.And, only depending on introducing cold air can not guarantee thermal balance and cause the occasion that temperature raises, add axle sleeve at peritrochanteric again, by allowing the cooling water flow warp beam sleeve, flow process gas is cooled off, suppress the rising of delivery temperature, keep temperature of rotor not rise, remove the accident that causes the rotor contact because of thermal expansion.

For example, the occasion of vacuum pump, suction port frequently is under the dissengaged positions.Its reason is owing to gas under high vacuum state is thin, the almost immobilising cause of gas.

In this state, drive the power of vacuum pump, almost all become heat energy,, raise, make rotor Da Gaowen, become the reason that breaks down even heat seldom also can cause temperature if do not take to get rid of these heats someway.

Remove the method for these heats, can adopt, rely on the rising of water temperature to absorb heat pump housing water-cooled; Also available wind cools off (air cooling) to get rid of heat to the pump housing.But, being in vacuum state in the pump housing, heat is difficult to shift.Therefore, introduce cold air, absorb heat easily, play simultaneously from exhaust port and introduce the effect of gas with discharges heat in the grease chamber that closes near the discharge side that degree of vacuum is not exerted an influence.

Moreover in case gas thins out under vacuum state, the foreign matter in the suction pump is residual easily and form the reason of helical rotor aspirated foreign body.This can discharge the foreign matters such as dust that are trapped in easily in the pump by injecting cold air from pump housing side case.

By implementing the present invention, the empty pump of the contaminated product phenomenon in the flow process gas that can prevent from easily to be referred to as in recent years provides small-sized, inexpensive dry vacuum pump to the exhaust pollution of airborne release.

Description of drawings

When Fig. 1 (1), Fig. 1 (2), Fig. 1 (3), Fig. 1 (4) rotate to diverse location for rotor in rotary course, the longitudinal sectional drawing at the main position of the rotor and the pump housing;

When Fig. 2 (1) rotates to Fig. 1 (1) position for rotor, the X-X sectional drawing at the main position of the rotor and the pump housing, when Fig. 2 (2) rotates to Fig. 1 (2) position for rotor, the X-X sectional drawing at the main position of the rotor and the pump housing, when Fig. 2 (3) rotates to Fig. 1 (3) position for rotor, when the X-X sectional drawing at the main position of the rotor and the pump housing, Fig. 2 (4) rotate to Fig. 1 (4) position for rotor, the X-X sectional drawing at the main position of the rotor and the pump housing;

Fig. 3 is the vacuum pump longitudinal sectional drawing;

Fig. 4 (1) is system pipeline first exemplary plot, and Fig. 4 (2) is system pipeline second exemplary plot, and Fig. 4 (3) is system pipeline the 3rd exemplary plot.

Label declaration:

1 pump housing, 18 coolers

2,3 rotors, 19 filters

4 side case A, 20 flowmeters

11 side case B, 21 regulators

A suction port B exhaust port

C cold air mouth E suction chamber

F medial compartment G discharges the chamber

Embodiment

With reference to legend enforcement example of the present invention is described.

Fig. 3 represents the screw type screw vaccum pump, and the pump housing 1 is inclusive with the

rotor

2,3 of right-hand screw line and left hand screw line.

Label 4 is space of containing above-mentioned helical thread portion and the side case A that constitutes discharge side partition wall.

Bearing bracket 5 is contained on the side case A4, is equipped with on the bearing bracket 5 in order to the rotating shaft 2a of the discharge side of supporting

rotor

2 and 3 and the bearing 6 of 3a, and in order to the axle envelope 7 of

seal shaft

2a and 3a.

On the left end face of side case A4 motor bracket 8 is housed.Symbol 9 is expressed as motor drive shaft, relies on shaft coupling 10 that rotary driving force is delivered to rotor 2.

The space that holds

rotor

2,3 spiral parts is housed on its right end face of the pump housing 1 and constitutes the side case B11 of suction side partition wall.Bearing bracket 12 embeds in the side case B11, is equipped with on the bearing bracket 12 in order to the rotating shaft 2b of the suction side of supporting

rotor

2,3 and the bearing 13 of 3b, and the axle envelope 14 of seal shaft 2b and 3b.

Fixed gear 15 is fixed on the end of a 2b by key, and fixed gear 15 is meshed with adjustable gear 16 on being installed in a 3b.

Thereby the rotary driving force of rotor 2 is delivered on the rotor 3 by gear 15,16.17 is gear-box.On the internal face of the pump housing 1, offer suction port A, having exhaust port B as holding spiral space and constituting on the wall of side case A4 of partition wall.

The exhaust port B of exhaust port B and side case A4 ₁Be communicated with.And, on the internal face of the pump housing, having cold air mouth C, atmosphere or cooled gas can be sent in the pump housing 1 (referring to Fig. 2).

Shown in Fig. 4 (1), with exhaust port B ₁On the gas exhaust piping D that links to each other, ram's horns D ₁, and ram's horns D _1aThe centre cooler 18 is housed, part can be sent into cold air mouth C after discharging gas cooling.

Perhaps shown in Fig. 4 (2), also can be by behind the filter 19, air is inhaled into cold air mouth C.

Perhaps shown in Fig. 4 (3), also can be from the outside to N ₂Carry out flow control Deng gas, resupply cold air mouth C.

Symbol S represents the suction line that is connected with suction port A.

The spiral that relies on the pump housing 1 and

rotor

2,3 to constitute contains the chamber as shown in Figure 2, and it is divided into suction chamber E, medial compartment F and discharges chamber G.(closing the grease chamber is F, G)

Suction chamber E comprises suction port A usually, and medial compartment F comprises cold air mouth C, discharges chamber G and arranges after compression to exhaust port B under a constant volume.

In other words, along with the rotation of

rotor

2,3, mutual boundary line (potted line), three chambers of E, F and G constantly moves, and medial compartment F keeps certain cubical content moving, and moves to discharging chamber G thereupon, and after being compressed to about 1/2 volume, exhaust port B is opened.

Fig. 1 (1) and Fig. 2 (1) expression: the screw thread end face of rotor 3 is closed exhaust port B.Especially turn to the state that to open from closed state; Cold air mouth C also blocks because of the outer rim of the worm tooth of

rotor

2 and 3 and is in closed condition.

Shown in Fig. 1 (2) and Fig. 2 (2), along with the rotation of

rotor

2 and 3, exhaust port B opens, and along with discharging dwindling of chamber G volume, the gas of discharging in the G of chamber is discharged from exhaust port B.

And medial compartment F is under the state that keeps a constant volume, and to exhaust port B one side shifting, cold air mouth C opens.

Cooled gas or atmosphere flow to (because under vacuum state) in the medial compartment F from cold air mouth C, gas in the medial compartment F is used for the inner wall surface of the outer surface and the pump housing 1 of cooled

rotor

2 and 3, play the effect of heat transfer medium simultaneously, and blow away attached to the foreign matter on the pump housing 1 and

rotor

2 and 3, play cleaning action.

Suction port A links to each other with suction chamber E, increase along with suction chamber E volume, gas from suction port A enter and left direction (exhaust port one side) move, when entering medial compartment F, produce the suction chamber that makes new advances again, but suction chamber E and medial compartment F separate, and the cold air that enters from cold air mouth C does not communicate with suction chamber.(certainly, can leak, can increase the quantity of closing the grease chamber,, keep efficient and do not reduce to reduce leakage rate by increasing the helical pitch number at screw thread position because of the gap produces.)

Also have, medial compartment is in vacuum state, and cold air mouth C has the effect that sucks cold air.

Thereby the cold air from the cold air mouth sucks even under the high vacuum field, when removing the heat of compression, plays the effect of hot medium again, and carries out exchange heat between the pump housing, emits heat easily outside the pump housing 1.In addition, also play and to be trapped in the material row that sucks in the pump housing 1 in the gas to exhaust port B.

By said method, can avoid between rotor and rotor and the pump housing between accident appears contacting.

Along with the rotation of

rotor

2,3, as shown in Fig. 1 and Fig. 2, (1) → (2) → (3) → change return (1) (4).

This enforcement example is expressed the bottom line of the reach of guaranteeing two Room that are not connected with suction chamber, suction stroke with discharge stroke in the middle of added some compression strokes.But, adopt the desired value (pressure ratio is more than 3) in vacuum territory among the present invention, can fully realize purpose of the present invention.

Claims

1, a kind of dry-type spiral vacuum pump, the rotor of dry-type spiral vacuum pump has that to form left hand screw line, the right-hand screw line of profile of tooth by circle outer trochoid, spiral of Archimedes, circular curve a pair of, it is characterized in that, the helical pitch number of dry-type spiral vacuum pump is decided to be 2 more than the helical pitch, is formed more than 2 by the pump housing inwall of helical rotor, the wall of side case A that the selenodont exhaust port is arranged and spiral seal line and closes the grease chamber; Along with the rotor rotation, the spiral seal line also moves thereupon, closes the grease chamber and also shifts to the discharge side from the suction side; On pump housing sidewall, have from discharging side and close the suction port that the grease chamber communicates with second, the position that this hole is offered should be able to guarantee the rotation along with rotor, closing the grease chamber with the longest time to above-mentioned second opens, this hole is introduced cold air to the rotor position and is cooled off, simultaneously, the dust thing that is trapped in the pump is discharged.