JPS6013956A - Oil cooling structure for gas engine - Google Patents

Abstract

PURPOSE:To permit to cool efficiently the inside of a piston, the inside of a piston rod, a gland seal section and one surface of a diaphragm by introducing oil into the piston rod of double tube structure through a guide piston equipped with an oil flow path. CONSTITUTION:The oil in a crank case 13 is introduced into the oil path 5a of a cooling oil pipe 5, inserted into and secured to the inside of the piston rod 3, from the oil path 8a of a guide cylinder and the transversal groove of the guide piston 7 through an oil pump and a radiator. The oil is turned in the upper oil reservoir 1b of the piston 1 and cools the inside of the piston rod 3 under whirling about the outer periphery of the cooling oil pipe 5. Then, the back surface of the diaphragm 12 is cooled by the oil injected from a fixture 4 used for attaching both an oil injection guide and the piston rod 3 through the oil path port 3b of the piston rod. The gland seal section 10 is cooled by the cooling oil from an oil path entrance port 16.

Description

[Detailed Description of the Invention] The present invention relates to compressors for gas compressors, dynamic pressure gas generators, Stirling cycle and other thermal cycle prime movers, refrigerators, etc. (hereinafter collectively referred to as gas machines). In order to improve the isothermal compression efficiency, refrigerator efficiency, engine efficiency, etc. of
The inside of the piston is heated with water-cooled or air-cooled oil, which is pressurized with an oil pump.
This invention relates to an oil cooling structure for a gas machine that is provided with a series of oil passages (also referred to as oil passages) to cool the inside of a diaphragm, a piston ring, etc., and return the guide piston to the crankcase.

Also, double-acting piston of Sfuring cycle.

Power pistons (also referred to as compression pistons), displacers (also referred to as expansion pistons, compression pistons), pistons for expansion-compression and other purposes in other thermal cycle refrigerators and prime movers, as well as compressor pistons (hereinafter referred to as pistons), etc. ,
A piston (collectively referred to as a piston) has a surface that is always wet with a working fluid (helium, hydrogen, fluorocarbon, other gases, mixed gases, two-phase fluids, etc., hereinafter referred to as fluid).

Since the friction of the piston rings and the heat of compression of the fluid cause the temperature to rise, cooling this would be one of the important methods for increasing the various efficiencies of the gas machine mentioned above. In addition, piston rings, diaphragms, and gland sealing materials that utilize characteristics such as flexibility, elasticity, and fluid impermeability to seal fluids are also susceptible to heat generation due to mechanical contact friction, expansion, and distortion accumulation. Constant cooling is important in order to prevent damage and improve durability and reliability.

In order to improve these aspects, the present invention relates to an oil cooling structure for a gas machine in which pistons and parts are pressurized by an oil pump and cooled (some directly, mainly indirectly) with air-cooled or water-cooled oil. In conventional gas engines,
The specification of Japanese Utility Model Application Publication No. 52'-37132 "Piston Engine" describes a piston engine that includes a piston body that is in sliding contact with the inner wall surface of the cylinder and is equipped with a sealing member, and that the inside of the cylinder is partitioned into a high temperature chamber and a low temperature chamber. A configuration has been described in which a circulation passage through which cooling oil circulates in one direction is provided in the piston rod for forced cooling, but this structure has the following drawbacks.

(1) The inside of the cylinder was divided into a high temperature chamber and a low temperature chamber.

When a grand seal is provided in the partition, it is difficult to cool the grand seal.

Therefore, the temperature of the seal increases due to frictional heat between the piston rod and the seal, causing it to expand, which tends to cause seizures due to deformation, and also significantly reduces sealing performance.

(2) In piston engines, a diaphragm is installed to seal the crank part of the cold room so that the gas from the dirty lubricating oil that lubricates the crank part does not enter the high temperature room. , deterioration is rapid, and reliability is significantly reduced over long-term use.

The present invention improves the above-mentioned drawbacks, and provides a piston engine or a gas engine in which a partition is provided between a high temperature chamber and a low temperature chamber, and a gland seal and a diaphragm are further disposed.

(A circulation path is provided in the piston and piston rod inside the 11tffl section, and a cooling oil spout is provided at the bottom of the piston rod to cool the diaphragm. Cooling oil is sent under pressure to actively cool the piston, piston rod, and diaphragm. 2) Furthermore, by installing screw-like fins on the surface of the cooling oil pipe inside the piston rod, the cooling area is increased.

The piston rod is cooled to prevent wear and deterioration of the gland seal.

Gas engines with this type of structure have significantly improved durability and reliability, and firstly, the durability of parts such as the gland seal material, diaphragm, and piston ring has improved. In other words, 2. Normal gland seals are generally cooled by water cooling from the outer circumferential surface, but from the outer circumferential surface of the gland seal there are (frictional heat is generated at the contact area), and the thermal conductivity of gland sealing materials using elasticity such as synthetic rubber is extremely poor (iron is 0.8 W/cm-
K is 0.0026 and 1/3 for nitrile rubber.
It is 00. ) Therefore, 2. With normal cooling methods, gland seals are exposed to the compression heat of the fluid and the heat of friction with the piston rings, which causes the temperature to rise, expand and deform, and the coefficient of friction increases, which can lead to seizing accidents. Also, the amount of wear increases and the fluid sealing performance deteriorates in a short period of time (to be exact, the diameter of the piston rod also increases as the temperature rises). Gland seals were the least reliable maintenance parts in gas machinery. Solving this problem was important for improving the efficiency and durability of gas machines.

Another feature is that cooled oil is constantly supplied to the heat generating section to prevent the temperature from rising. In other words, the piston rod (iron-based with high thermal conductivity) is cooled from inside (the same goes for the piston ring).
The inner peripheral surface of the gland seal is constantly cooled.

Furthermore, the diaphragm and guide piston were also equipped with simple oil passages, allowing for continuous cooling and lubrication at the same time. This is because multithread screws and fins are attached to the outer peripheral surface of the cooling oil pipe to cause the oil to swirl within the piston rod, thereby lengthening the oil path and increasing the heat transfer coefficient with the inner surface of the piston rod, thereby increasing cooling efficiency. To further increase efficiency, attach the aforementioned screws, fins, multi-start threads, etc. to the inner surface of the piston rod, and insert a cooling oil pipe into the piston rod.The frictional heat between the piston rod outer circumferential surface and the gland seal inner surface can be absorbed by the oil. Everything can be recovered and there is no rise in temperature of the gland seal.Secondly, the inside of the piston can be cooled, so the piston is cool! In addition to maintaining precision, the piston rings are constantly cooled, allowing gas machines to operate with nearly constant surface pressure on the cylinder, reducing fluid leakage and dead volume.

Volumetric efficiency is therefore improved.

Furthermore, since the wetted surface with the fluid is constantly cooled, compression efficiency is also increased.

The third is the inside of the piston, diaphragm, gland seal,
Oil was used instead of water to cool the jacket, etc.
It is now possible to provide highly efficient and highly reliable gas machines without worrying about accidents due to corrosion of structural materials, water contamination in fluids, or closure of cooling passages due to impurities in cooling water.

Here, comparing the cooling superiority of oil with water2, for example, the thermal conductivity coefficient is 75% to 9θ% of that of water according to experiments.
If the flow rate is increased, it becomes similar to water, and there is no need to worry about corrosion of the gas machine parts and structural materials used. Also, gas machines require high purity fluids.

Even if there is a small amount of oil mixed in, it is possible to increase the purity using a refiner or oil separator, but water can cause serious problems such as extremely low efficiency, corrosion and deterioration of internal parts of gas equipment, and condensation and solidification, resulting in operation stoppage. It may cause an accident.

An embodiment of the present invention will be specifically described below with reference to FIGS. 1 to 3.

1 is the piston + 1a is the seal, 2 is the cylinder head,
3 is a piston rod r3a is a through hole of the piston rod, and 3b is a through hole in a right angle direction and is a spouting port for cooling oil. The piston 1 and the piston rod 3 are fixed with a screw 4, 5 is a cooling oil pipe, 5a is a through hole, and 5c is a screw or fin provided on the surface to widen the cooling area and achieve cooling. The cooling oil pipe 5 is inserted and fixed inside the piston rod 3. 6 An oil pipe 7 provided in the upper oil reservoir 1G of the piston 1 is a guide piston, which slides inside the guide cylinder 8. Reference numeral 7a denotes a cooling oil supply path for the guide piston 7, and the sliding portion thereof has an elongated long groove 7b that penetrates toward the center. 8a is a cooling oil supply port of the guide cylinder, 9 is a partition between the compression space 14 in the high temperature room and the backup space 11 in the low temperature room, and is provided with a gland seal 1o. A diaphragm 12 is fixed to the piston rod by fittings 12a and 12b, and its end is attached to the cylinder wall to prevent lubricant gas from rising from the crankcase 13. 15 is a grand seal cooling passage, 16 is an oil passage inlet, 17 is a cooling jacket; 1
8 is an oil outlet. FIG. 3 shows a piston rod and a guide piston integrated into one body, 5 is a cooling oil pipe inserted and fixed into the piston rod, and 19 is an outlet for cooling oil to the diaphragm.

Next, to explain its function, first, as for the cooling method, the oil in the crankcase 13 is increased in pressure and cooled by an oil pump and a radiator (not shown), and the oil passage 8a of the guide cylinder and the vertical groove of the guide piston 7 are cooled. Oil passage 5 of cooling oil pipe 5 from oil passage 7b
a, reverse the rotation at the upper part 1b of the piston 1, and rotate the piston 9 with the multithread screw 5b on the outer periphery of the cooling oil pipe 5.
The inside of the piston rod 3 is cooled and lowered to open the piston rod oil passage hole 3b.

The oil injection guide and the piston rod 3 are attached to the flam by vapor-depositing aluminum or other metals to enhance the cooling effect. ) is injected into the inside of the crankcase containing oil vapor to cool it, lubricate the guide piston 7, and return to the inside of the crankcase 13 from between the guide cylinder 8 and the piston rod. By doing this continuously, cooling and lubrication can be achieved.

Fig. 3 shows an example of internal cooling of a compression piston, in which the piston rod 3 is manufactured integrally with a guide piston 7, and the piston 1 is inserted into the hollow piston rod 3, which is fixed with a metal fitting 4. A cooling oil pipe 5 for cooling the gland seal 10 as a return path is connected to a metal fitting 4 on the piston-P side.
Fixed at -.

C-do-/ Next, the cooling oil passage will be explained.

Oil that has been pressurized and cooled from inside the crankcase by an oil pump passes through oil passages 7a, 7b, and oil passage 5a in the center of cooling oil pipe 5 from oil passage 8a, and enters oil reservoir 1b in the piston. Here, the heat is absorbed from the piston 1 and cools the gland seal 10 via the piston rod 3 while circulating from the oil pipe 6 to the oil hole 3a of the piston rod and the outer periphery of the cooling oil pipe 5 (inside the hollow piston rod). Oil hole 3b or 19
It returns to the inside of the crankcase 13 while lubricating the idle piston 7.

By providing an oil reservoir inside the piston and cooling it from the inside, the entire piston has a substantially uniform temperature, making it easier to control the dimensional accuracy of the piston, such as roundness and perpendicularity. That is,
Also, the dead volume of the fluid is small.

Since the piston ring can be cooled from the inside, its durability is increased, and since the fluid is compressed while the piston is cooled from the inside, the isothermal compression efficiency is also improved.

1. Other embodiments of the present invention include a single-acting non-lubricant compressor, a Stirling cycle refrigerator, a compression piston portion 9 of an engine, etc., but the gland seal 10. Only the piston and diaphragm are cooled because the stuffing box 2 etc. are not required.

Furthermore, as another embodiment, a cooling oil passage system can be formed in which the stuffing box and cylinder jacket 17 shown in FIG. 3 are cooled with oil and then enter the oil passage 8a of the guide cylinder described above. Further, from the oil passage inlet 16, the gland seal cooling passage 15. It is also possible to cool the series of oil cooling systems including the jacket 17 and the oil outlet 18 and the cooling system from the oil passage 8a of the guide cylinder by supplying oil in parallel.

[Brief explanation of drawings]

FIG. 1 is a partially omitted enlarged view of an embodiment of the invention, FIG. 2 is an enlarged enlarged external view of a cooling oil pipe partially cut away, and FIG. 3 is an integrated view of a piston rod and a guide piston. 1...piston, 3... which are sectional views of other embodiments.
Piston rod, 5... Cooling oil pipe, 5b... Screw or fin, 6... Oil pipe, 7... Guide piston, 9
... Partition, 10... Grand seal, 12...
Diaphragm 13...Crankcase, 17...Cylinder jacket Patent applicant 1 Ishishi W4 Yoko Co., Ltd. Representative Reio Nakai

Claims (4)

[Claims] (1) Pass the ura through a guide piston with an oil flow path, double pipe +
Introduced into an I-built piston rond, any two of the above sets inside the piston, inside the piston rond, the gland seal part, and one side of the diaphragm. Or an oil cooling structure for a gas machine, characterized in that it has a structure in which oil is cooled by supplying oil by communicating oil flow paths to two or more combinations. (2) A gas machine according to claim 1, characterized in that a pipe is inserted into the axial center of a hollow piston rond that connects the guide piston and the piston, and the inside of the piston rond is used as a reciprocating path for oil. oil cooling structure. (3) A tube with multiple threads, fins, etc. attached to the outer periphery is inserted into the axial center of the hollow piston rond that connects the guide piston and the piston, or oil swirls on the inner surface of the hollow piston rond and cools it. An oil cooling structure for a gas machine according to claim 1, characterized in that a screw, a fin, etc. are attached so as to descend in the direction of the guide piston, and a pipe is further inserted to provide a reciprocating path for cooling the piston rond and for oil. . (4) Oil that has been pressurized by an oil pump and water-cooled, air-cooled, etc. is passed through a cylinder jacket, a radiator, in series or in parallel, or through a guide piston with an oil flow path to a piston with a double pipe structure. Introduced into the rond, inside the piston, from inside the piston rond, the grand seal part,
Any two sets or two sets of the above on one side of the diaphragm